92 files changed, 2234 insertions, 992 deletions
diff --git a/application/History.php b/application/History.php
index 4fd2f294..d230f39d 100644
--- a/application/History.php
+++ b/application/History.php
@@ -1,9 +1,11 @@
 <?php
 namespace Shaarli;
 use DateTime;
 use Exception;
 use Shaarli\Bookmark\Bookmark;
+use Shaarli\Helper\FileUtils;
 /**
 * Class History
@@ -30,27 +32,27 @@ class History
    /**
     * @var string Action key: a new link has been created.
     */
-    const CREATED = 'CREATED';
+    public const CREATED = 'CREATED';
    /**
     * @var string Action key: a link has been updated.
     */
-    const UPDATED = 'UPDATED';
+    public const UPDATED = 'UPDATED';
    /**
     * @var string Action key: a link has been deleted.
     */
-    const DELETED = 'DELETED';
+    public const DELETED = 'DELETED';
    /**
     * @var string Action key: settings have been updated.
     */
-    const SETTINGS = 'SETTINGS';
+    public const SETTINGS = 'SETTINGS';
    /**
     * @var string Action key: a bulk import has been processed.
     */
-    const IMPORT = 'IMPORT';
+    public const IMPORT = 'IMPORT';
    /**
     * @var string History file path.
diff --git a/application/Languages.php b/application/Languages.php
index d83e0765..7177db2c 100644
--- a/application/Languages.php
+++ b/application/Languages.php
@@ -41,7 +41,7 @@ class Languages
    /**
     * Core translations domain
     */
-    const DEFAULT_DOMAIN = 'shaarli';
+    public const DEFAULT_DOMAIN = 'shaarli';
    /**
     * @var TranslatorInterface
@@ -76,7 +76,8 @@ class Languages
            $this->language = $confLanguage;
        }
-        if (! extension_loaded('gettext')
+        if (
+            ! extension_loaded('gettext')
            || in_array($this->conf->get('translation.mode', 'auto'), ['auto', 'php'])
        ) {
            $this->initPhpTranslator();
@@ -98,7 +99,7 @@ class Languages
        $this->translator->loadDomain(self::DEFAULT_DOMAIN, 'inc/languages');
        // Default extension translation from the current theme
-        $themeTransFolder = rtrim($this->conf->get('raintpl_tpl'), '/') .'/'. $this->conf->get('theme') .'/language';
+        $themeTransFolder = rtrim($this->conf->get('raintpl_tpl'), '/') . '/' . $this->conf->get('theme') . '/language';
        if (is_dir($themeTransFolder)) {
            $this->translator->loadDomain($this->conf->get('theme'), $themeTransFolder, false);
        }
@@ -121,7 +122,9 @@ class Languages
        $translations = new Translations();
        // Core translations
        try {
-            $translations = $translations->addFromPoFile('inc/languages/'. $this->language .'/LC_MESSAGES/shaarli.po');
+            $translations = $translations->addFromPoFile(
+                'inc/languages/' . $this->language . '/LC_MESSAGES/shaarli.po'
+            );
            $translations->setDomain('shaarli');
            $this->translator->loadTranslations($translations);
        } catch (\InvalidArgumentException $e) {
@@ -129,11 +132,11 @@ class Languages
        // Default extension translation from the current theme
        $theme = $this->conf->get('theme');
-        $themeTransFolder = rtrim($this->conf->get('raintpl_tpl'), '/') .'/'. $theme .'/language';
+        $themeTransFolder = rtrim($this->conf->get('raintpl_tpl'), '/') . '/' . $theme . '/language';
        if (is_dir($themeTransFolder)) {
            try {
                $translations = Translations::fromPoFile(
-                    $themeTransFolder .'/'. $this->language .'/LC_MESSAGES/'. $theme .'.po'
+                    $themeTransFolder . '/' . $this->language . '/LC_MESSAGES/' . $theme . '.po'
                );
                $translations->setDomain($theme);
                $this->translator->loadTranslations($translations);
@@ -149,7 +152,7 @@ class Languages
            try {
                $extension = Translations::fromPoFile(
-                    $translationPath . $this->language .'/LC_MESSAGES/'. $domain .'.po'
+                    $translationPath . $this->language . '/LC_MESSAGES/' . $domain . '.po'
                );
                $extension->setDomain($domain);
                $this->translator->loadTranslations($extension);
@@ -183,6 +186,7 @@ class Languages
            'en' => t('English'),
            'fr' => t('French'),
            'jp' => t('Japanese'),
+            'ru' => t('Russian'),
        ];
    }
 }
diff --git a/application/Thumbnailer.php b/application/Thumbnailer.php
index 5aec23c8..c4ff8d7a 100644
--- a/application/Thumbnailer.php
+++ b/application/Thumbnailer.php
@@ -13,7 +13,7 @@ use WebThumbnailer\WebThumbnailer;
 */
 class Thumbnailer
 {
-    const COMMON_MEDIA_DOMAINS = [
+    protected const COMMON_MEDIA_DOMAINS = [
        'imgur.com',
        'flickr.com',
        'youtube.com',
@@ -31,9 +31,9 @@ class Thumbnailer
        'deviantart.com',
    ];
-    const MODE_ALL = 'all';
+    public const MODE_ALL = 'all';
-    const MODE_COMMON = 'common';
+    public const MODE_COMMON = 'common';
-    const MODE_NONE = 'none';
+    public const MODE_NONE = 'none';
    /**
     * @var WebThumbnailer instance.
@@ -60,7 +60,7 @@ class Thumbnailer
            // TODO: create a proper error handling system able to catch exceptions...
            die(t(
                'php-gd extension must be loaded to use thumbnails. '
-                .'Thumbnails are now disabled. Please reload the page.'
+                . 'Thumbnails are now disabled. Please reload the page.'
            ));
        }
@@ -81,7 +81,8 @@ class Thumbnailer
     */
    public function get($url)
    {
-        if ($this->conf->get('thumbnails.mode') === self::MODE_COMMON
+        if (
+            $this->conf->get('thumbnails.mode') === self::MODE_COMMON
            && ! $this->isCommonMediaOrImage($url)
        ) {
            return false;
diff --git a/application/TimeZone.php b/application/TimeZone.php
index c1869ef8..a420eb96 100644
--- a/application/TimeZone.php
+++ b/application/TimeZone.php
@@ -1,4 +1,5 @@
 <?php
 /**
 * Generates a list of available timezone continents and cities.
 *
@@ -43,7 +44,7 @@ function generateTimeZoneData($installedTimeZones, $preselectedTimezone = '')
        // Try to split the provided timezone
        $spos = strpos($preselectedTimezone, '/');
        $pcontinent = substr($preselectedTimezone, 0, $spos);
-        $pcity = substr($preselectedTimezone, $spos+1);
+        $pcity = substr($preselectedTimezone, $spos + 1);
    }
    $continents = [];
@@ -60,7 +61,7 @@ function generateTimeZoneData($installedTimeZones, $preselectedTimezone = '')
        }
        $continent = substr($tz, 0, $spos);
-        $city = substr($tz, $spos+1);
+        $city = substr($tz, $spos + 1);
        $cities[] = ['continent' => $continent, 'city' => $city];
        $continents[$continent] = true;
    }
@@ -85,7 +86,7 @@ function generateTimeZoneData($installedTimeZones, $preselectedTimezone = '')
 function isTimeZoneValid($continent, $city)
 {
    return in_array(
-        $continent.'/'.$city,
+        $continent . '/' . $city,
        timezone_identifiers_list()
    );
 }
diff --git a/application/Utils.php b/application/Utils.php
index bcfda65c..952378ab 100644
--- a/application/Utils.php
+++ b/application/Utils.php
@@ -1,24 +1,27 @@
 <?php
 /**
 * Shaarli utilities
 */
 /**
- * Logs a message to a text file
+ * Format log using provided data.
 *
- * The log format is compatible with fail2ban.
+ * @param string      $message  the message to log
+ * @param string|null $clientIp the client's remote IPv4/IPv6 address
 *
- * @param string $logFile  where to write the logs
+ * @return string Formatted message to log
- * @param string $clientIp the client's remote IPv4/IPv6 address
- * @param string $message  the message to log
 */
-function logm($logFile, $clientIp, $message)
+function format_log(string $message, string $clientIp = null): string
 {
-    file_put_contents(
+    $out = $message;
-        $logFile,
-        date('Y/m/d H:i:s').' - '.$clientIp.' - '.strval($message).PHP_EOL,
+    if (!empty($clientIp)) {
-        FILE_APPEND
+        // Note: we keep the first dash to avoid breaking fail2ban configs
-    );
+        $out = '- ' . $clientIp . ' - ' . $out;
+    }
+    return $out;
 }
 /**
@@ -100,7 +103,7 @@ function escape($input)
    }
    if (is_array($input)) {
-        $out = array();
+        $out = [];
        foreach ($input as $key => $value) {
            $out[escape($key)] = escape($value);
        }
@@ -161,7 +164,7 @@ function checkDateFormat($format, $string)
 *
 * @return string $referer - final referer.
 */
-function generateLocation($referer, $host, $loopTerms = array())
+function generateLocation($referer, $host, $loopTerms = [])
 {
    $finalReferer = './?';
@@ -194,7 +197,7 @@ function generateLocation($referer, $host, $loopTerms = array())
 function autoLocale($headerLocale)
 {
    // Default if browser does not send HTTP_ACCEPT_LANGUAGE
-    $locales = array('en_US', 'en_US.utf8', 'en_US.UTF-8');
+    $locales = ['en_US', 'en_US.utf8', 'en_US.UTF-8'];
    if (! empty($headerLocale)) {
        if (preg_match_all('/([a-z]{2,3})[-_]?([a-z]{2})?,?/i', $headerLocale, $matches, PREG_SET_ORDER)) {
            $attempts = [];
@@ -325,6 +328,23 @@ function format_date($date, $time = true, $intl = true)
 }
 /**
+ * Format the date month according to the locale.
+ *
+ * @param DateTimeInterface $date to format.
+ *
+ * @return bool|string Formatted date, or false if the input is invalid.
+ */
+function format_month(DateTimeInterface $date)
+{
+    if (! $date instanceof DateTimeInterface) {
+        return false;
+    }
+    return strftime('%B', $date->getTimestamp());
+}
+/**
 * Check if the input is an integer, no matter its real type.
 *
 * PHP is a bit messy regarding this:
@@ -357,13 +377,15 @@ function return_bytes($val)
        return $val;
    }
    $val = trim($val);
-    $last = strtolower($val[strlen($val)-1]);
+    $last = strtolower($val[strlen($val) - 1]);
    $val = intval(substr($val, 0, -1));
    switch ($last) {
        case 'g':
            $val *= 1024;
+        // do no break in order 1024^2 for each unit
        case 'm':
            $val *= 1024;
+        // do no break in order 1024^2 for each unit
        case 'k':
            $val *= 1024;
    }
@@ -452,14 +474,28 @@ function alphabetical_sort(&$data, $reverse = false, $byKeys = false)
 * Wrapper function for translation which match the API
 * of gettext()/_() and ngettext().
 *
- * @param string $text   Text to translate.
+ * @param string $text      Text to translate.
- * @param string $nText  The plural message ID.
+ * @param string $nText     The plural message ID.
- * @param int    $nb     The number of items for plural forms.
+ * @param int    $nb        The number of items for plural forms.
- * @param string $domain The domain where the translation is stored (default: shaarli).
+ * @param string $domain    The domain where the translation is stored (default: shaarli).
+ * @param array  $variables Associative array of variables to replace in translated text.
+ * @param bool   $fixCase   Apply `ucfirst` on the translated string, might be useful for strings with variables.
 *
 * @return string Text translated.
 */
-function t($text, $nText = '', $nb = 1, $domain = 'shaarli')
+function t($text, $nText = '', $nb = 1, $domain = 'shaarli', $variables = [], $fixCase = false)
+{
+    $postFunction = $fixCase ? 'ucfirst' : function ($input) {
+        return $input;
+    };
+    return $postFunction(dn__($domain, $text, $nText, $nb, $variables));
+}
+/**
+ * Converts an exception into a printable stack trace string.
+ */
+function exception2text(Throwable $e): string
 {
-    return dn__($domain, $text, $nText, $nb);
+    return $e->getMessage() . PHP_EOL . $e->getFile() . $e->getLine() . PHP_EOL . $e->getTraceAsString();
 }
diff --git a/application/api/ApiMiddleware.php b/application/api/ApiMiddleware.php
index adc8b266..9fb88358 100644
--- a/application/api/ApiMiddleware.php
+++ b/application/api/ApiMiddleware.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Api;
 use malkusch\lock\mutex\FlockMutex;
@@ -108,7 +109,8 @@ class ApiMiddleware
     */
    protected function checkToken($request)
    {
-        if (!$request->hasHeader('Authorization')
+        if (
+            !$request->hasHeader('Authorization')
            && !isset($this->container->environment['REDIRECT_HTTP_AUTHORIZATION'])
        ) {
            throw new ApiAuthorizationException('JWT token not provided');
diff --git a/application/api/ApiUtils.php b/application/api/ApiUtils.php
index eb1ca9bc..9228bb2d 100644
--- a/application/api/ApiUtils.php
+++ b/application/api/ApiUtils.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Api;
 use Shaarli\Api\Exceptions\ApiAuthorizationException;
@@ -27,7 +28,7 @@ class ApiUtils
            throw new ApiAuthorizationException('Malformed JWT token');
        }
-        $genSign = Base64Url::encode(hash_hmac('sha512', $parts[0] .'.'. $parts[1], $secret, true));
+        $genSign = Base64Url::encode(hash_hmac('sha512', $parts[0] . '.' . $parts[1], $secret, true));
        if ($parts[2] != $genSign) {
            throw new ApiAuthorizationException('Invalid JWT signature');
        }
@@ -42,7 +43,8 @@ class ApiUtils
            throw new ApiAuthorizationException('Invalid JWT payload');
        }
-        if (empty($payload->iat)
+        if (
+            empty($payload->iat)
            || $payload->iat > time()
            || time() - $payload->iat > ApiMiddleware::$TOKEN_DURATION
        ) {
@@ -89,13 +91,17 @@ class ApiUtils
     * If no URL is provided, it will generate a local note URL.
     * If no title is provided, it will use the URL as title.
     *
-     * @param array|null  $input          Request Link.
+     * @param array|null $input          Request Link.
-     * @param bool        $defaultPrivate Setting defined if a bookmark is private by default.
+     * @param bool       $defaultPrivate Setting defined if a bookmark is private by default.
+     * @param string     $tagsSeparator  Tags separator loaded from the config file.
     *
     * @return Bookmark instance.
     */
-    public static function buildBookmarkFromRequest(?array $input, bool $defaultPrivate): Bookmark
+    public static function buildBookmarkFromRequest(
-    {
+        ?array $input,
+        bool $defaultPrivate,
+        string $tagsSeparator
+    ): Bookmark {
        $bookmark = new Bookmark();
        $url = ! empty($input['url']) ? cleanup_url($input['url']) : '';
        if (isset($input['private'])) {
@@ -107,6 +113,15 @@ class ApiUtils
        $bookmark->setTitle(! empty($input['title']) ? $input['title'] : '');
        $bookmark->setUrl($url);
        $bookmark->setDescription(! empty($input['description']) ? $input['description'] : '');
+        // Be permissive with provided tags format
+        if (is_string($input['tags'] ?? null)) {
+            $input['tags'] = tags_str2array($input['tags'], $tagsSeparator);
+        }
+        if (is_array($input['tags'] ?? null) && count($input['tags']) === 1 && is_string($input['tags'][0])) {
+            $input['tags'] = tags_str2array($input['tags'][0], $tagsSeparator);
+        }
        $bookmark->setTags(! empty($input['tags']) ? $input['tags'] : []);
        $bookmark->setPrivate($private);
diff --git a/application/api/controllers/HistoryController.php b/application/api/controllers/HistoryController.php
index 505647a9..d83a3a25 100644
--- a/application/api/controllers/HistoryController.php
+++ b/application/api/controllers/HistoryController.php
@@ -1,6 +1,5 @@
 <?php
 namespace Shaarli\Api\Controllers;
 use Shaarli\Api\Exceptions\ApiBadParametersException;
diff --git a/application/api/controllers/Info.php b/application/api/controllers/Info.php
index 12f6b2f0..ae7db93e 100644
--- a/application/api/controllers/Info.php
+++ b/application/api/controllers/Info.php
@@ -29,13 +29,13 @@ class Info extends ApiController
        $info = [
            'global_counter' => $this->bookmarkService->count(),
            'private_counter' => $this->bookmarkService->count(BookmarkFilter::$PRIVATE),
-            'settings' => array(
+            'settings' => [
                'title' => $this->conf->get('general.title', 'Shaarli'),
                'header_link' => $this->conf->get('general.header_link', '?'),
                'timezone' => $this->conf->get('general.timezone', 'UTC'),
                'enabled_plugins' => $this->conf->get('general.enabled_plugins', []),
                'default_private_links' => $this->conf->get('privacy.default_private_links', false),
-            ),
+            ],
        ];
        return $response->withJson($info, 200, $this->jsonStyle);
diff --git a/application/api/controllers/Links.php b/application/api/controllers/Links.php
index 73a1b84e..b83b2260 100644
--- a/application/api/controllers/Links.php
+++ b/application/api/controllers/Links.php
@@ -117,9 +117,14 @@ class Links extends ApiController
    public function postLink($request, $response)
    {
        $data = (array) ($request->getParsedBody() ?? []);
-        $bookmark = ApiUtils::buildBookmarkFromRequest($data, $this->conf->get('privacy.default_private_links'));
+        $bookmark = ApiUtils::buildBookmarkFromRequest(
+            $data,
+            $this->conf->get('privacy.default_private_links'),
+            $this->conf->get('general.tags_separator', ' ')
+        );
        // duplicate by URL, return 409 Conflict
-        if (! empty($bookmark->getUrl())
+        if (
+            ! empty($bookmark->getUrl())
            && ! empty($dup = $this->bookmarkService->findByUrl($bookmark->getUrl()))
        ) {
            return $response->withJson(
@@ -131,7 +136,7 @@ class Links extends ApiController
        $this->bookmarkService->add($bookmark);
        $out = ApiUtils::formatLink($bookmark, index_url($this->ci['environment']));
-        $redirect = $this->ci->router->relativePathFor('getLink', ['id' => $bookmark->getId()]);
+        $redirect = $this->ci->router->pathFor('getLink', ['id' => $bookmark->getId()]);
        return $response->withAddedHeader('Location', $redirect)
                        ->withJson($out, 201, $this->jsonStyle);
    }
@@ -157,9 +162,14 @@ class Links extends ApiController
        $index = index_url($this->ci['environment']);
        $data = $request->getParsedBody();
-        $requestBookmark = ApiUtils::buildBookmarkFromRequest($data, $this->conf->get('privacy.default_private_links'));
+        $requestBookmark = ApiUtils::buildBookmarkFromRequest(
+            $data,
+            $this->conf->get('privacy.default_private_links'),
+            $this->conf->get('general.tags_separator', ' ')
+        );
        // duplicate URL on a different link, return 409 Conflict
-        if (! empty($requestBookmark->getUrl())
+        if (
+            ! empty($requestBookmark->getUrl())
            && ! empty($dup = $this->bookmarkService->findByUrl($requestBookmark->getUrl()))
            && $dup->getId() != $id
        ) {
diff --git a/application/api/exceptions/ApiAuthorizationException.php b/application/api/exceptions/ApiAuthorizationException.php
index 0e3f4776..c77e9eea 100644
--- a/application/api/exceptions/ApiAuthorizationException.php
+++ b/application/api/exceptions/ApiAuthorizationException.php
@@ -28,7 +28,7 @@ class ApiAuthorizationException extends ApiException
     */
    public function setMessage($message)
    {
-        $original = $this->debug === true ? ': '. $this->getMessage() : '';
+        $original = $this->debug === true ? ': ' . $this->getMessage() : '';
        $this->message = $message . $original;
    }
 }
diff --git a/application/api/exceptions/ApiException.php b/application/api/exceptions/ApiException.php
index d6b66323..7deafb96 100644
--- a/application/api/exceptions/ApiException.php
+++ b/application/api/exceptions/ApiException.php
@@ -44,7 +44,7 @@ abstract class ApiException extends \Exception
        }
        return [
            'message' => $this->getMessage(),
-            'stacktrace' => get_class($this) .': '. $this->getTraceAsString()
+            'stacktrace' => get_class($this) . ': ' . $this->getTraceAsString()
        ];
    }
diff --git a/application/bookmark/Bookmark.php b/application/bookmark/Bookmark.php
index ea565d1f..4238ef25 100644
--- a/application/bookmark/Bookmark.php
+++ b/application/bookmark/Bookmark.php
@@ -19,7 +19,7 @@ use Shaarli\Bookmark\Exception\InvalidBookmarkException;
 class Bookmark
 {
    /** @var string Date format used in string (former ID format) */
-    const LINK_DATE_FORMAT = 'Ymd_His';
+    public const LINK_DATE_FORMAT = 'Ymd_His';
    /** @var int Bookmark ID */
    protected $id;
@@ -60,11 +60,13 @@ class Bookmark
    /**
     * Initialize a link from array data. Especially useful to create a Bookmark from former link storage format.
     *
-     * @param array $data
+     * @param array  $data
+     * @param string $tagsSeparator Tags separator loaded from the config file.
+     *                              This is a context data, and it should *never* be stored in the Bookmark object.
     *
     * @return $this
     */
-    public function fromArray(array $data): Bookmark
+    public function fromArray(array $data, string $tagsSeparator = ' '): Bookmark
    {
        $this->id = $data['id'] ?? null;
        $this->shortUrl = $data['shorturl'] ?? null;
@@ -77,7 +79,7 @@ class Bookmark
        if (is_array($data['tags'])) {
            $this->tags = $data['tags'];
        } else {
-            $this->tags = preg_split('/\s+/', $data['tags'] ?? '', -1, PREG_SPLIT_NO_EMPTY);
+            $this->tags = tags_str2array($data['tags'] ?? '', $tagsSeparator);
        }
        if (! empty($data['updated'])) {
            $this->updated = $data['updated'];
@@ -104,7 +106,8 @@ class Bookmark
     */
    public function validate(): void
    {
-        if ($this->id === null
+        if (
+            $this->id === null
            || ! is_int($this->id)
            || empty($this->shortUrl)
            || empty($this->created)
@@ -112,7 +115,7 @@ class Bookmark
            throw new InvalidBookmarkException($this);
        }
        if (empty($this->url)) {
-            $this->url = '/shaare/'. $this->shortUrl;
+            $this->url = '/shaare/' . $this->shortUrl;
        }
        if (empty($this->title)) {
            $this->title = $this->url;
@@ -348,7 +351,12 @@ class Bookmark
     */
    public function setTags(?array $tags): Bookmark
    {
-        $this->setTagsString(implode(' ', $tags ?? []));
+        $this->tags = array_map(
+            function (string $tag): string {
+                return $tag[0] === '-' ? substr($tag, 1) : $tag;
+            },
+            tags_filter($tags, ' ')
+        );
        return $this;
    }
@@ -378,6 +386,24 @@ class Bookmark
    }
    /**
+     * Return true if:
+     *   - the bookmark's thumbnail is not already set to false (= not found)
+     *   - it's not a note
+     *   - it's an HTTP(S) link
+     *   - the thumbnail has not yet be retrieved (null) or its associated cache file doesn't exist anymore
+     *
+     * @return bool True if the bookmark's thumbnail needs to be retrieved.
+     */
+    public function shouldUpdateThumbnail(): bool
+    {
+        return $this->thumbnail !== false
+            && !$this->isNote()
+            && startsWith(strtolower($this->url), 'http')
+            && (null === $this->thumbnail || !is_file($this->thumbnail))
+        ;
+    }
+    /**
     * Get the Sticky.
     *
     * @return bool
@@ -402,11 +428,13 @@ class Bookmark
    }
    /**
-     * @return string Bookmark's tags as a string, separated by a space
+     * @param string $separator Tags separator loaded from the config file.
+     *
+     * @return string Bookmark's tags as a string, separated by a separator
     */
-    public function getTagsString(): string
+    public function getTagsString(string $separator = ' '): string
    {
-        return implode(' ', $this->getTags());
+        return tags_array2str($this->getTags(), $separator);
    }
    /**
@@ -426,19 +454,13 @@ class Bookmark
     *   - trailing dash in tags will be removed
     *
     * @param string|null $tags
+     * @param string      $separator Tags separator loaded from the config file.
     *
     * @return $this
     */
-    public function setTagsString(?string $tags): Bookmark
+    public function setTagsString(?string $tags, string $separator = ' '): Bookmark
    {
-        // Remove first '-' char in tags.
+        $this->setTags(tags_str2array($tags, $separator));
-        $tags = preg_replace('/(^| )\-/', '$1', $tags ?? '');
-        // Explode all tags separted by spaces or commas
-        $tags = preg_split('/[\s,]+/', $tags);
-        // Remove eventual empty values
-        $tags = array_values(array_filter($tags));
-        $this->tags = $tags;
        return $this;
    }
@@ -489,7 +511,7 @@ class Bookmark
     */
    public function renameTag(string $fromTag, string $toTag): void
    {
-        if (($pos = array_search($fromTag, $this->tags)) !== false) {
+        if (($pos = array_search($fromTag, $this->tags ?? [])) !== false) {
            $this->tags[$pos] = trim($toTag);
        }
    }
@@ -501,7 +523,7 @@ class Bookmark
     */
    public function deleteTag(string $tag): void
    {
-        if (($pos = array_search($tag, $this->tags)) !== false) {
+        if (($pos = array_search($tag, $this->tags ?? [])) !== false) {
            unset($this->tags[$pos]);
            $this->tags = array_values($this->tags);
        }
diff --git a/application/bookmark/BookmarkArray.php b/application/bookmark/BookmarkArray.php
index 67bb3b73..b9328116 100644
--- a/application/bookmark/BookmarkArray.php
+++ b/application/bookmark/BookmarkArray.php
@@ -72,7 +72,8 @@ class BookmarkArray implements \Iterator, \Countable, \ArrayAccess
     */
    public function offsetSet($offset, $value)
    {
-        if (! $value instanceof Bookmark
+        if (
+            ! $value instanceof Bookmark
            || $value->getId() === null || empty($value->getUrl())
            || ($offset !== null && ! is_int($offset)) || ! is_int($value->getId())
            || $offset !== null && $offset !== $value->getId()
@@ -222,7 +223,8 @@ class BookmarkArray implements \Iterator, \Countable, \ArrayAccess
     */
    public function getByUrl(string $url): ?Bookmark
    {
-        if (! empty($url)
+        if (
+            ! empty($url)
            && isset($this->urls[$url])
            && isset($this->bookmarks[$this->urls[$url]])
        ) {
diff --git a/application/bookmark/BookmarkFileService.php b/application/bookmark/BookmarkFileService.php
index eb7899bf..6666a251 100644
--- a/application/bookmark/BookmarkFileService.php
+++ b/application/bookmark/BookmarkFileService.php
@@ -69,7 +69,7 @@ class BookmarkFileService implements BookmarkServiceInterface
        } else {
            try {
                $this->bookmarks = $this->bookmarksIO->read();
-            } catch (EmptyDataStoreException|DatastoreNotInitializedException $e) {
+            } catch (EmptyDataStoreException | DatastoreNotInitializedException $e) {
                $this->bookmarks = new BookmarkArray();
                if ($this->isLoggedIn) {
@@ -85,25 +85,29 @@ class BookmarkFileService implements BookmarkServiceInterface
            if (! $this->bookmarks instanceof BookmarkArray) {
                $this->migrate();
                exit(
-                    'Your data store has been migrated, please reload the page.'. PHP_EOL .
+                    'Your data store has been migrated, please reload the page.' . PHP_EOL .
                    'If this message keeps showing up, please delete data/updates.txt file.'
                );
            }
        }
-        $this->bookmarkFilter = new BookmarkFilter($this->bookmarks);
+        $this->bookmarkFilter = new BookmarkFilter($this->bookmarks, $this->conf);
    }
    /**
     * @inheritDoc
     */
-    public function findByHash(string $hash): Bookmark
+    public function findByHash(string $hash, string $privateKey = null): Bookmark
    {
        $bookmark = $this->bookmarkFilter->filter(BookmarkFilter::$FILTER_HASH, $hash);
        // PHP 7.3 introduced array_key_first() to avoid this hack
        $first = reset($bookmark);
-        if (! $this->isLoggedIn && $first->isPrivate()) {
+        if (
-            throw new Exception('Not authorized');
+            !$this->isLoggedIn
+            && $first->isPrivate()
+            && (empty($privateKey) || $privateKey !== $first->getAdditionalContentEntry('private_key'))
+        ) {
+            throw new BookmarkNotFoundException();
        }
        return $first;
@@ -162,7 +166,8 @@ class BookmarkFileService implements BookmarkServiceInterface
        }
        $bookmark = $this->bookmarks[$id];
-        if (($bookmark->isPrivate() && $visibility != 'all' && $visibility != 'private')
+        if (
+            ($bookmark->isPrivate() && $visibility != 'all' && $visibility != 'private')
            || (! $bookmark->isPrivate() && $visibility != 'all' && $visibility != 'public')
        ) {
            throw new Exception('Unauthorized');
@@ -262,7 +267,8 @@ class BookmarkFileService implements BookmarkServiceInterface
        }
        $bookmark = $this->bookmarks[$id];
-        if (($bookmark->isPrivate() && $visibility != 'all' && $visibility != 'private')
+        if (
+            ($bookmark->isPrivate() && $visibility != 'all' && $visibility != 'private')
            || (! $bookmark->isPrivate() && $visibility != 'all' && $visibility != 'public')
        ) {
            return false;
@@ -304,7 +310,8 @@ class BookmarkFileService implements BookmarkServiceInterface
        $caseMapping = [];
        foreach ($bookmarks as $bookmark) {
            foreach ($bookmark->getTags() as $tag) {
-                if (empty($tag)
+                if (
+                    empty($tag)
                    || (! $this->isLoggedIn && startsWith($tag, '.'))
                    || $tag === BookmarkMarkdownFormatter::NO_MD_TAG
                    || in_array($tag, $filteringTags, true)
@@ -340,26 +347,42 @@ class BookmarkFileService implements BookmarkServiceInterface
    /**
     * @inheritDoc
     */
-    public function days(): array
+    public function findByDate(
-    {
+        \DateTimeInterface $from,
-        $bookmarkDays = [];
+        \DateTimeInterface $to,
-        foreach ($this->search() as $bookmark) {
+        ?\DateTimeInterface &$previous,
-            $bookmarkDays[$bookmark->getCreated()->format('Ymd')] = 0;
+        ?\DateTimeInterface &$next
+    ): array {
+        $out = [];
+        $previous = null;
+        $next = null;
+        foreach ($this->search([], null, false, false, true) as $bookmark) {
+            if ($to < $bookmark->getCreated()) {
+                $next = $bookmark->getCreated();
+            } elseif ($from < $bookmark->getCreated() && $to > $bookmark->getCreated()) {
+                $out[] = $bookmark;
+            } else {
+                if ($previous !== null) {
+                    break;
+                }
+                $previous = $bookmark->getCreated();
+            }
        }
-        $bookmarkDays = array_keys($bookmarkDays);
-        sort($bookmarkDays);
-        return array_map('strval', $bookmarkDays);
+        return $out;
    }
    /**
     * @inheritDoc
     */
-    public function filterDay(string $request)
+    public function getLatest(): ?Bookmark
    {
-        $visibility = $this->isLoggedIn ? BookmarkFilter::$ALL : BookmarkFilter::$PUBLIC;
+        foreach ($this->search([], null, false, false, true) as $bookmark) {
+            return $bookmark;
+        }
-        return $this->bookmarkFilter->filter(BookmarkFilter::$FILTER_DAY, $request, false, $visibility);
+        return null;
    }
    /**
@@ -386,14 +409,14 @@ class BookmarkFileService implements BookmarkServiceInterface
            false
        );
        $updater = new LegacyUpdater(
-            UpdaterUtils::read_updates_file($this->conf->get('resource.updates')),
+            UpdaterUtils::readUpdatesFile($this->conf->get('resource.updates')),
            $bookmarkDb,
            $this->conf,
            true
        );
        $newUpdates = $updater->update();
        if (! empty($newUpdates)) {
-            UpdaterUtils::write_updates_file(
+            UpdaterUtils::writeUpdatesFile(
                $this->conf->get('resource.updates'),
                $updater->getDoneUpdates()
            );
diff --git a/application/bookmark/BookmarkFilter.php b/application/bookmark/BookmarkFilter.php
index c79386ea..db83c51c 100644
--- a/application/bookmark/BookmarkFilter.php
+++ b/application/bookmark/BookmarkFilter.php
@@ -6,6 +6,7 @@ namespace Shaarli\Bookmark;
 use Exception;
 use Shaarli\Bookmark\Exception\BookmarkNotFoundException;
+use Shaarli\Config\ConfigManager;
 /**
 * Class LinkFilter.
@@ -58,12 +59,16 @@ class BookmarkFilter
     */
    private $bookmarks;
+    /** @var ConfigManager */
+    protected $conf;
    /**
     * @param Bookmark[] $bookmarks initialization.
     */
-    public function __construct($bookmarks)
+    public function __construct($bookmarks, ConfigManager $conf)
    {
        $this->bookmarks = $bookmarks;
+        $this->conf = $conf;
    }
    /**
@@ -107,10 +112,14 @@ class BookmarkFilter
                    $filtered = $this->bookmarks;
                }
                if (!empty($request[0])) {
-                    $filtered = (new BookmarkFilter($filtered))->filterTags($request[0], $casesensitive, $visibility);
+                    $filtered = (new BookmarkFilter($filtered, $this->conf))
+                        ->filterTags($request[0], $casesensitive, $visibility)
+                    ;
                }
                if (!empty($request[1])) {
-                    $filtered = (new BookmarkFilter($filtered))->filterFulltext($request[1], $visibility);
+                    $filtered = (new BookmarkFilter($filtered, $this->conf))
+                        ->filterFulltext($request[1], $visibility)
+                    ;
                }
                return $filtered;
            case self::$FILTER_TEXT:
@@ -141,7 +150,7 @@ class BookmarkFilter
            return $this->bookmarks;
        }
-        $out = array();
+        $out = [];
        foreach ($this->bookmarks as $key => $value) {
            if ($value->isPrivate() && $visibility === 'private') {
                $out[$key] = $value;
@@ -280,8 +289,9 @@ class BookmarkFilter
     *
     * @return string generated regex fragment
     */
-    private static function tag2regex(string $tag): string
+    protected function tag2regex(string $tag): string
    {
+        $tagsSeparator = $this->conf->get('general.tags_separator', ' ');
        $len = strlen($tag);
        if (!$len || $tag === "-" || $tag === "*") {
            // nothing to search, return empty regex
@@ -295,12 +305,13 @@ class BookmarkFilter
            $i = 0; // start at first character
            $regex = '(?='; // use positive lookahead
        }
-        $regex .= '.*(?:^| )'; // before tag may only be a space or the beginning
+        // before tag may only be the separator or the beginning
+        $regex .= '.*(?:^|' . $tagsSeparator . ')';
        // iterate over string, separating it into placeholder and content
        for (; $i < $len; $i++) {
            if ($tag[$i] === '*') {
                // placeholder found
-                $regex .= '[^ ]*?';
+                $regex .= '[^' . $tagsSeparator . ']*?';
            } else {
                // regular characters
                $offset = strpos($tag, '*', $i);
@@ -316,7 +327,8 @@ class BookmarkFilter
                $i = $offset;
            }
        }
-        $regex .= '(?:$| ))'; // after the tag may only be a space or the end
+        // after the tag may only be the separator or the end
+        $regex .= '(?:$|' . $tagsSeparator . '))';
        return $regex;
    }
@@ -334,14 +346,15 @@ class BookmarkFilter
     */
    public function filterTags($tags, bool $casesensitive = false, string $visibility = 'all')
    {
+        $tagsSeparator = $this->conf->get('general.tags_separator', ' ');
        // get single tags (we may get passed an array, even though the docs say different)
        $inputTags = $tags;
        if (!is_array($tags)) {
            // we got an input string, split tags
-            $inputTags = preg_split('/(?:\s+)|,/', $inputTags, -1, PREG_SPLIT_NO_EMPTY);
+            $inputTags = tags_str2array($inputTags, $tagsSeparator);
        }
-        if (!count($inputTags)) {
+        if (count($inputTags) === 0) {
            // no input tags
            return $this->noFilter($visibility);
        }
@@ -358,7 +371,7 @@ class BookmarkFilter
        }
        // build regex from all tags
-        $re = '/^' . implode(array_map("self::tag2regex", $inputTags)) . '.*$/';
+        $re = '/^' . implode(array_map([$this, 'tag2regex'], $inputTags)) . '.*$/';
        if (!$casesensitive) {
            // make regex case insensitive
            $re .= 'i';
@@ -378,10 +391,11 @@ class BookmarkFilter
                    continue;
                }
            }
-            $search = $link->getTagsString(); // build search string, start with tags of current link
+            // build search string, start with tags of current link
+            $search = $link->getTagsString($tagsSeparator);
            if (strlen(trim($link->getDescription())) && strpos($link->getDescription(), '#') !== false) {
                // description given and at least one possible tag found
-                $descTags = array();
+                $descTags = [];
                // find all tags in the form of #tag in the description
                preg_match_all(
                    '/(?<![' . self::$HASHTAG_CHARS . '])#([' . self::$HASHTAG_CHARS . ']+?)\b/sm',
@@ -390,9 +404,9 @@ class BookmarkFilter
                );
                if (count($descTags[1])) {
                    // there were some tags in the description, add them to the search string
-                    $search .= ' ' . implode(' ', $descTags[1]);
+                    $search .= $tagsSeparator . tags_array2str($descTags[1], $tagsSeparator);
                }
-            };
+            }
            // match regular expression with search string
            if (!preg_match($re, $search)) {
                // this entry does _not_ match our regex
@@ -422,7 +436,7 @@ class BookmarkFilter
                }
            }
-            if (empty(trim($link->getTagsString()))) {
+            if (empty($link->getTags())) {
                $filtered[$key] = $link;
            }
        }
@@ -537,10 +551,11 @@ class BookmarkFilter
     */
    protected function buildFullTextSearchableLink(Bookmark $link, array &$lengths): string
    {
-        $content  = mb_convert_case($link->getTitle(), MB_CASE_LOWER, 'UTF-8') .'\\';
+        $tagString = $link->getTagsString($this->conf->get('general.tags_separator', ' '));
-        $content .= mb_convert_case($link->getDescription(), MB_CASE_LOWER, 'UTF-8') .'\\';
+        $content  = mb_convert_case($link->getTitle(), MB_CASE_LOWER, 'UTF-8') . '\\';
-        $content .= mb_convert_case($link->getUrl(), MB_CASE_LOWER, 'UTF-8') .'\\';
+        $content .= mb_convert_case($link->getDescription(), MB_CASE_LOWER, 'UTF-8') . '\\';
-        $content .= mb_convert_case($link->getTagsString(), MB_CASE_LOWER, 'UTF-8') .'\\';
+        $content .= mb_convert_case($link->getUrl(), MB_CASE_LOWER, 'UTF-8') . '\\';
+        $content .= mb_convert_case($tagString, MB_CASE_LOWER, 'UTF-8') . '\\';
        $lengths['title'] = ['start' => 0, 'end' => mb_strlen($link->getTitle())];
        $nextField = $lengths['title']['end'] + 1;
@@ -548,7 +563,7 @@ class BookmarkFilter
        $nextField = $lengths['description']['end'] + 1;
        $lengths['url'] = ['start' => $nextField, 'end' => $nextField + mb_strlen($link->getUrl())];
        $nextField = $lengths['url']['end'] + 1;
-        $lengths['tags'] = ['start' => $nextField, 'end' => $nextField + mb_strlen($link->getTagsString())];
+        $lengths['tags'] = ['start' => $nextField, 'end' => $nextField + mb_strlen($tagString)];
        return $content;
    }
diff --git a/application/bookmark/BookmarkIO.php b/application/bookmark/BookmarkIO.php
index f40fa476..8439d470 100644
--- a/application/bookmark/BookmarkIO.php
+++ b/application/bookmark/BookmarkIO.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace Shaarli\Bookmark;
+use malkusch\lock\exception\LockAcquireException;
 use malkusch\lock\mutex\Mutex;
 use malkusch\lock\mutex\NoMutex;
 use Shaarli\Bookmark\Exception\DatastoreNotInitializedException;
@@ -80,7 +81,7 @@ class BookmarkIO
        }
        $content = null;
-        $this->mutex->synchronized(function () use (&$content) {
+        $this->synchronized(function () use (&$content) {
            $content = file_get_contents($this->datastore);
        });
@@ -112,18 +113,35 @@ class BookmarkIO
        if (is_file($this->datastore) && !is_writeable($this->datastore)) {
            // The datastore exists but is not writeable
            throw new NotWritableDataStoreException($this->datastore);
-        } else if (!is_file($this->datastore) && !is_writeable(dirname($this->datastore))) {
+        } elseif (!is_file($this->datastore) && !is_writeable(dirname($this->datastore))) {
            // The datastore does not exist and its parent directory is not writeable
            throw new NotWritableDataStoreException(dirname($this->datastore));
        }
-        $data = self::$phpPrefix.base64_encode(gzdeflate(serialize($links))).self::$phpSuffix;
+        $data = self::$phpPrefix . base64_encode(gzdeflate(serialize($links))) . self::$phpSuffix;
-        $this->mutex->synchronized(function () use ($data) {
+        $this->synchronized(function () use ($data) {
            file_put_contents(
                $this->datastore,
                $data
            );
        });
    }
+    /**
+     * Wrapper applying mutex to provided function.
+     * If the lock can't be acquired (e.g. some shared hosting provider), we execute the function without mutex.
+     *
+     * @see https://github.com/shaarli/Shaarli/issues/1650
+     *
+     * @param callable $function
+     */
+    protected function synchronized(callable $function): void
+    {
+        try {
+            $this->mutex->synchronized($function);
+        } catch (LockAcquireException $exception) {
+            $function();
+        }
+    }
 }
diff --git a/application/bookmark/BookmarkInitializer.php b/application/bookmark/BookmarkInitializer.php
index 04b996f3..8ab5c441 100644
--- a/application/bookmark/BookmarkInitializer.php
+++ b/application/bookmark/BookmarkInitializer.php
@@ -13,6 +13,9 @@ namespace Shaarli\Bookmark;
 * To prevent data corruption, it does not overwrite existing bookmarks,
 * even though there should not be any.
 *
+ * We disable this because otherwise it creates indentation issues, and heredoc is not supported by PHP gettext.
+ * @phpcs:disable Generic.Files.LineLength.TooLong
+ *
 * @package Shaarli\Bookmark
 */
 class BookmarkInitializer
@@ -36,10 +39,10 @@ class BookmarkInitializer
    public function initialize(): void
    {
        $bookmark = new Bookmark();
-        $bookmark->setTitle('quicksilver (loop) on Vimeo ' . t('(private bookmark with thumbnail demo)'));
+        $bookmark->setTitle('Calm Jazz Music - YouTube ' . t('(private bookmark with thumbnail demo)'));
-        $bookmark->setUrl('https://vimeo.com/153493904');
+        $bookmark->setUrl('https://www.youtube.com/watch?v=DVEUcbPkb-c');
        $bookmark->setDescription(t(
-'Shaarli will automatically pick up the thumbnail for links to a variety of websites.
+            'Shaarli will automatically pick up the thumbnail for links to a variety of websites.
 Explore your new Shaarli instance by trying out controls and menus.
 Visit the project on [Github](https://github.com/shaarli/Shaarli) or [the documentation](https://shaarli.readthedocs.io/en/master/) to learn more about Shaarli.
@@ -54,7 +57,7 @@ Now you can edit or delete the default shaares.
        $bookmark = new Bookmark();
        $bookmark->setTitle(t('Note: Shaare descriptions'));
        $bookmark->setDescription(t(
-'Adding a shaare without entering a URL creates a text-only "note" post such as this one.
+            'Adding a shaare without entering a URL creates a text-only "note" post such as this one.
 This note is private, so you are the only one able to see it while logged in.
 You can use this to keep notes, post articles, code snippets, and much more.
@@ -91,7 +94,7 @@ Markdown also supports tables:
            'Shaarli - ' . t('The personal, minimalist, super-fast, database free, bookmarking service')
        );
        $bookmark->setDescription(t(
-'Welcome to Shaarli!
+            'Welcome to Shaarli!
 Shaarli allows you to bookmark your favorite pages, and share them with others or store them privately.
 You can add a description to your bookmarks, such as this one, and tag them.
diff --git a/application/bookmark/BookmarkServiceInterface.php b/application/bookmark/BookmarkServiceInterface.php
index 37a54d03..08cdbb4e 100644
--- a/application/bookmark/BookmarkServiceInterface.php
+++ b/application/bookmark/BookmarkServiceInterface.php
@@ -20,13 +20,14 @@ interface BookmarkServiceInterface
    /**
     * Find a bookmark by hash
     *
-     * @param string $hash
+     * @param string      $hash       Bookmark's hash
+     * @param string|null $privateKey Optional key used to access private links while logged out
     *
     * @return Bookmark
     *
     * @throws \Exception
     */
-    public function findByHash(string $hash): Bookmark;
+    public function findByHash(string $hash, string $privateKey = null);
    /**
     * @param $url
@@ -155,22 +156,29 @@ interface BookmarkServiceInterface
    public function bookmarksCountPerTag(array $filteringTags = [], ?string $visibility = null): array;
    /**
-     * Returns the list of days containing articles (oldest first)
+     * Return a list of bookmark matching provided period of time.
+     * It also update directly previous and next date outside of given period found in the datastore.
     *
-     * @return array containing days (in format YYYYMMDD).
+     * @param \DateTimeInterface      $from     Starting date.
+     * @param \DateTimeInterface      $to       Ending date.
+     * @param \DateTimeInterface|null $previous (by reference) updated with first created date found before $from.
+     * @param \DateTimeInterface|null $next     (by reference) updated with first created date found after $to.
+     *
+     * @return array List of bookmarks matching provided period of time.
     */
-    public function days(): array;
+    public function findByDate(
+        \DateTimeInterface $from,
+        \DateTimeInterface $to,
+        ?\DateTimeInterface &$previous,
+        ?\DateTimeInterface &$next
+    ): array;
    /**
-     * Returns the list of articles for a given day.
+     * Returns the latest bookmark by creation date.
-     *
-     * @param string $request day to filter. Format: YYYYMMDD.
     *
-     * @return Bookmark[] list of shaare found.
+     * @return Bookmark|null Found Bookmark or null if the datastore is empty.
-     *
-     * @throws BookmarkNotFoundException
     */
-    public function filterDay(string $request);
+    public function getLatest(): ?Bookmark;
    /**
     * Creates the default database after a fresh install.
diff --git a/application/bookmark/LinkUtils.php b/application/bookmark/LinkUtils.php
index faf5dbfd..0ab2d213 100644
--- a/application/bookmark/LinkUtils.php
+++ b/application/bookmark/LinkUtils.php
@@ -67,17 +67,20 @@ function html_extract_tag($tag, $html)
    $propertiesKey = ['property', 'name', 'itemprop'];
    $properties = implode('|', $propertiesKey);
    // We need a OR here to accept either 'property=og:noquote' or 'property="og:unrelated og:my-tag"'
-    $orCondition  = '["\']?(?:og:)?'. $tag .'["\']?|["\'][^\'"]*?(?:og:)?' . $tag . '[^\'"]*?[\'"]';
+    $orCondition  = '["\']?(?:og:)?' . $tag . '["\']?|["\'][^\'"]*?(?:og:)?' . $tag . '[^\'"]*?[\'"]';
-    // Try to retrieve OpenGraph image.
+    // Support quotes in double quoted content, and the other way around
-    $ogRegex = '#<meta[^>]+(?:'. $properties .')=(?:'. $orCondition .')[^>]*content=["\'](.*?)["\'].*?>#';
+    $content = 'content=(["\'])((?:(?!\1).)*)\1';
+    // Try to retrieve OpenGraph tag.
+    $ogRegex = '#<meta[^>]+(?:' . $properties . ')=(?:' . $orCondition . ')[^>]*' . $content . '.*?>#';
    // If the attributes are not in the order property => content (e.g. Github)
    // New regex to keep this readable... more or less.
-    $ogRegexReverse = '#<meta[^>]+content=["\'](.*?)["\'][^>]+(?:'. $properties .')=(?:'. $orCondition .').*?>#';
+    $ogRegexReverse = '#<meta[^>]+' . $content . '[^>]+(?:' . $properties . ')=(?:' . $orCondition . ').*?>#';
-    if (preg_match($ogRegex, $html, $matches) > 0
+    if (
+        preg_match($ogRegex, $html, $matches) > 0
        || preg_match($ogRegexReverse, $html, $matches) > 0
    ) {
-        return $matches[1];
+        return $matches[2];
    }
    return false;
@@ -116,7 +119,7 @@ function hashtag_autolink($description, $indexUrl = '')
     * \p{Mn} - any non marking space (accents, umlauts, etc)
     */
    $regex = '/(^|\s)#([\p{Pc}\p{N}\p{L}\p{Mn}]+)/mui';
-    $replacement = '$1<a href="'. $indexUrl .'./add-tag/$2" title="Hashtag $2">#$2</a>';
+    $replacement = '$1<a href="' . $indexUrl . './add-tag/$2" title="Hashtag $2">#$2</a>';
    return preg_replace($regex, $replacement, $description);
 }
@@ -138,12 +141,17 @@ function space2nbsp($text)
 *
 * @param string $description shaare's description.
 * @param string $indexUrl    URL to Shaarli's index.
+ * @param bool   $autolink    Turn on/off automatic linkifications of URLs and hashtags
+ *
 * @return string formatted description.
 */
-function format_description($description, $indexUrl = '')
+function format_description($description, $indexUrl = '', $autolink = true)
 {
-    return nl2br(space2nbsp(hashtag_autolink(text2clickable($description), $indexUrl)));
+    if ($autolink) {
+        $description = hashtag_autolink(text2clickable($description), $indexUrl);
+    }
+    return nl2br(space2nbsp($description));
 }
 /**
@@ -171,3 +179,49 @@ function is_note($linkUrl)
 {
    return isset($linkUrl[0]) && $linkUrl[0] === '?';
 }
+/**
+ * Extract an array of tags from a given tag string, with provided separator.
+ *
+ * @param string|null $tags      String containing a list of tags separated by $separator.
+ * @param string      $separator Shaarli's default: ' ' (whitespace)
+ *
+ * @return array List of tags
+ */
+function tags_str2array(?string $tags, string $separator): array
+{
+    // For whitespaces, we use the special \s regex character
+    $separator = $separator === ' ' ? '\s' : $separator;
+    return preg_split('/\s*' . $separator . '+\s*/', trim($tags) ?? '', -1, PREG_SPLIT_NO_EMPTY);
+}
+/**
+ * Return a tag string with provided separator from a list of tags.
+ * Note that given array is clean up by tags_filter().
+ *
+ * @param array|null $tags      List of tags
+ * @param string     $separator
+ *
+ * @return string
+ */
+function tags_array2str(?array $tags, string $separator): string
+{
+    return implode($separator, tags_filter($tags, $separator));
+}
+/**
+ * Clean an array of tags: trim + remove empty entries
+ *
+ * @param array|null $tags List of tags
+ * @param string     $separator
+ *
+ * @return array
+ */
+function tags_filter(?array $tags, string $separator): array
+{
+    $trimDefault = " \t\n\r\0\x0B";
+    return array_values(array_filter(array_map(function (string $entry) use ($separator, $trimDefault): string {
+        return trim($entry, $trimDefault . $separator);
+    }, $tags ?? [])));
+}
diff --git a/application/bookmark/exception/BookmarkNotFoundException.php b/application/bookmark/exception/BookmarkNotFoundException.php
index 827a3d35..a91d1efa 100644
--- a/application/bookmark/exception/BookmarkNotFoundException.php
+++ b/application/bookmark/exception/BookmarkNotFoundException.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Bookmark\Exception;
 use Exception;
diff --git a/application/bookmark/exception/EmptyDataStoreException.php b/application/bookmark/exception/EmptyDataStoreException.php
index cd48c1e6..16a98470 100644
--- a/application/bookmark/exception/EmptyDataStoreException.php
+++ b/application/bookmark/exception/EmptyDataStoreException.php
@@ -1,7 +1,7 @@
 <?php
 namespace Shaarli\Bookmark\Exception;
+class EmptyDataStoreException extends \Exception
-class EmptyDataStoreException extends \Exception {}
+{
+}
diff --git a/application/bookmark/exception/InvalidBookmarkException.php b/application/bookmark/exception/InvalidBookmarkException.php
index 10c84a6d..fe184f8c 100644
--- a/application/bookmark/exception/InvalidBookmarkException.php
+++ b/application/bookmark/exception/InvalidBookmarkException.php
@@ -16,14 +16,14 @@ class InvalidBookmarkException extends \Exception
            } else {
                $created = 'Not a DateTime object';
            }
-            $this->message = 'This bookmark is not valid'. PHP_EOL;
+            $this->message = 'This bookmark is not valid' . PHP_EOL;
-            $this->message .= ' - ID: '. $bookmark->getId() . PHP_EOL;
+            $this->message .= ' - ID: ' . $bookmark->getId() . PHP_EOL;
-            $this->message .= ' - Title: '. $bookmark->getTitle() . PHP_EOL;
+            $this->message .= ' - Title: ' . $bookmark->getTitle() . PHP_EOL;
-            $this->message .= ' - Url: '. $bookmark->getUrl() . PHP_EOL;
+            $this->message .= ' - Url: ' . $bookmark->getUrl() . PHP_EOL;
-            $this->message .= ' - ShortUrl: '. $bookmark->getShortUrl() . PHP_EOL;
+            $this->message .= ' - ShortUrl: ' . $bookmark->getShortUrl() . PHP_EOL;
-            $this->message .= ' - Created: '. $created . PHP_EOL;
+            $this->message .= ' - Created: ' . $created . PHP_EOL;
        } else {
-            $this->message = 'The provided data is not a bookmark'. PHP_EOL;
+            $this->message = 'The provided data is not a bookmark' . PHP_EOL;
            $this->message .= var_export($bookmark, true);
        }
    }
diff --git a/application/bookmark/exception/NotWritableDataStoreException.php b/application/bookmark/exception/NotWritableDataStoreException.php
index 95f34b50..df91f3bc 100644
--- a/application/bookmark/exception/NotWritableDataStoreException.php
+++ b/application/bookmark/exception/NotWritableDataStoreException.php
@@ -1,9 +1,7 @@
 <?php
 namespace Shaarli\Bookmark\Exception;
 class NotWritableDataStoreException extends \Exception
 {
    /**
@@ -13,7 +11,7 @@ class NotWritableDataStoreException extends \Exception
     */
    public function __construct($dataStore)
    {
-        $this->message = 'Couldn\'t load data from the data store file "'. $dataStore .'". '.
+        $this->message = 'Couldn\'t load data from the data store file "' . $dataStore . '". ' .
            'Your data might be corrupted, or your file isn\'t readable.';
    }
 }
diff --git a/application/config/ConfigIO.php b/application/config/ConfigIO.php
index 3efe5b6f..a623bc8b 100644
--- a/application/config/ConfigIO.php
+++ b/application/config/ConfigIO.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Config;
 /**
diff --git a/application/config/ConfigJson.php b/application/config/ConfigJson.php
index c0c0dab9..23b22269 100644
--- a/application/config/ConfigJson.php
+++ b/application/config/ConfigJson.php
@@ -19,7 +19,7 @@ class ConfigJson implements ConfigIO
        $data = file_get_contents($filepath);
        $data = str_replace(self::getPhpHeaders(), '', $data);
        $data = str_replace(self::getPhpSuffix(), '', $data);
-        $data = json_decode($data, true);
+        $data = json_decode(trim($data), true);
        if ($data === null) {
            $errorCode = json_last_error();
            $error  = sprintf(
@@ -73,7 +73,7 @@ class ConfigJson implements ConfigIO
     */
    public static function getPhpHeaders()
    {
-        return '<?php /*'. PHP_EOL;
+        return '<?php /*';
    }
    /**
@@ -85,6 +85,6 @@ class ConfigJson implements ConfigIO
     */
    public static function getPhpSuffix()
    {
-        return PHP_EOL . '*/ ?>';
+        return '*/ ?>';
    }
 }
diff --git a/application/config/ConfigManager.php b/application/config/ConfigManager.php
index 4c98be30..717a038f 100644
--- a/application/config/ConfigManager.php
+++ b/application/config/ConfigManager.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Config;
 use Shaarli\Config\Exception\MissingFieldConfigException;
@@ -20,7 +21,7 @@ class ConfigManager
     */
    protected static $NOT_FOUND = 'NOT_FOUND';
-    public static $DEFAULT_PLUGINS = array('qrcode');
+    public static $DEFAULT_PLUGINS = ['qrcode'];
    /**
     * @var string Config folder.
@@ -133,7 +134,7 @@ class ConfigManager
    public function set($setting, $value, $write = false, $isLoggedIn = false)
    {
        if (empty($setting) || ! is_string($setting)) {
-            throw new \Exception(t('Invalid setting key parameter. String expected, got: '). gettype($setting));
+            throw new \Exception(t('Invalid setting key parameter. String expected, got: ') . gettype($setting));
        }
        // During the ConfigIO transition, map legacy settings to the new ones.
@@ -160,7 +161,7 @@ class ConfigManager
    public function remove($setting, $write = false, $isLoggedIn = false)
    {
        if (empty($setting) || ! is_string($setting)) {
-            throw new \Exception(t('Invalid setting key parameter. String expected, got: '). gettype($setting));
+            throw new \Exception(t('Invalid setting key parameter. String expected, got: ') . gettype($setting));
        }
        // During the ConfigIO transition, map legacy settings to the new ones.
@@ -213,7 +214,7 @@ class ConfigManager
    public function write($isLoggedIn)
    {
        // These fields are required in configuration.
-        $mandatoryFields = array(
+        $mandatoryFields = [
            'credentials.login',
            'credentials.hash',
            'credentials.salt',
@@ -222,7 +223,7 @@ class ConfigManager
            'general.title',
            'general.header_link',
            'privacy.default_private_links',
-        );
+        ];
        // Only logged in user can alter config.
        if (is_file($this->getConfigFileExt()) && !$isLoggedIn) {
@@ -366,10 +367,12 @@ class ConfigManager
        $this->setEmpty('general.links_per_page', 20);
        $this->setEmpty('general.enabled_plugins', self::$DEFAULT_PLUGINS);
        $this->setEmpty('general.default_note_title', 'Note: ');
-        $this->setEmpty('general.retrieve_description', false);
+        $this->setEmpty('general.retrieve_description', true);
+        $this->setEmpty('general.enable_async_metadata', true);
+        $this->setEmpty('general.tags_separator', ' ');
-        $this->setEmpty('updates.check_updates', false);
+        $this->setEmpty('updates.check_updates', true);
-        $this->setEmpty('updates.check_updates_branch', 'stable');
+        $this->setEmpty('updates.check_updates_branch', 'latest');
        $this->setEmpty('updates.check_updates_interval', 86400);
        $this->setEmpty('feed.rss_permalinks', true);
@@ -390,7 +393,7 @@ class ConfigManager
        $this->setEmpty('translation.mode', 'php');
        $this->setEmpty('translation.extensions', []);
-        $this->setEmpty('plugins', array());
+        $this->setEmpty('plugins', []);
        $this->setEmpty('formatter', 'markdown');
    }
diff --git a/application/config/ConfigPhp.php b/application/config/ConfigPhp.php
index cad34594..53d6a7a3 100644
--- a/application/config/ConfigPhp.php
+++ b/application/config/ConfigPhp.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Config;
 /**
@@ -12,7 +13,7 @@ class ConfigPhp implements ConfigIO
    /**
     * @var array List of config key without group.
     */
-    public static $ROOT_KEYS = array(
+    public static $ROOT_KEYS = [
        'login',
        'hash',
        'salt',
@@ -22,7 +23,7 @@ class ConfigPhp implements ConfigIO
        'redirector',
        'disablesessionprotection',
        'privateLinkByDefault',
-    );
+    ];
    /**
     * Map legacy config keys with the new ones.
@@ -31,7 +32,7 @@ class ConfigPhp implements ConfigIO
     *
     * @var array current key => legacy key.
     */
-    public static $LEGACY_KEYS_MAPPING = array(
+    public static $LEGACY_KEYS_MAPPING = [
        'credentials.login' => 'login',
        'credentials.hash' => 'hash',
        'credentials.salt' => 'salt',
@@ -68,7 +69,7 @@ class ConfigPhp implements ConfigIO
        'privacy.hide_public_links' => 'config.HIDE_PUBLIC_LINKS',
        'privacy.hide_timestamps' => 'config.HIDE_TIMESTAMPS',
        'security.open_shaarli' => 'config.OPEN_SHAARLI',
-    );
+    ];
    /**
     * @inheritdoc
@@ -76,12 +77,12 @@ class ConfigPhp implements ConfigIO
    public function read($filepath)
    {
        if (! file_exists($filepath) || ! is_readable($filepath)) {
-            return array();
+            return [];
        }
        include $filepath;
-        $out = array();
+        $out = [];
        foreach (self::$ROOT_KEYS as $key) {
            $out[$key] = isset($GLOBALS[$key]) ? $GLOBALS[$key] : '';
        }
@@ -95,7 +96,7 @@ class ConfigPhp implements ConfigIO
     */
    public function write($filepath, $conf)
    {
-        $configStr = '<?php '. PHP_EOL;
+        $configStr = '<?php ' . PHP_EOL;
        foreach (self::$ROOT_KEYS as $key) {
            if (isset($conf[$key])) {
                $configStr .= '$GLOBALS[\'' . $key . '\'] = ' . var_export($conf[$key], true) . ';' . PHP_EOL;
@@ -106,8 +107,8 @@ class ConfigPhp implements ConfigIO
        foreach ($conf['config'] as $key => $value) {
            $configStr .= '$GLOBALS[\'config\'][\''
                . $key
-                .'\'] = '
+                . '\'] = '
-                .var_export($conf['config'][$key], true).';'
+                . var_export($conf['config'][$key], true) . ';'
                . PHP_EOL;
        }
@@ -115,18 +116,19 @@ class ConfigPhp implements ConfigIO
            foreach ($conf['plugins'] as $key => $value) {
                $configStr .= '$GLOBALS[\'plugins\'][\''
                    . $key
-                    .'\'] = '
+                    . '\'] = '
-                    .var_export($conf['plugins'][$key], true).';'
+                    . var_export($conf['plugins'][$key], true) . ';'
                    . PHP_EOL;
            }
        }
-        if (!file_put_contents($filepath, $configStr)
+        if (
+            !file_put_contents($filepath, $configStr)
            || strcmp(file_get_contents($filepath), $configStr) != 0
        ) {
            throw new \Shaarli\Exceptions\IOException(
                $filepath,
-                t('Shaarli could not create the config file. '.
+                t('Shaarli could not create the config file. ' .
                  'Please make sure Shaarli has the right to write in the folder is it installed in.')
            );
        }
diff --git a/application/config/ConfigPlugin.php b/application/config/ConfigPlugin.php
index ea8dfbda..6cadef12 100644
--- a/application/config/ConfigPlugin.php
+++ b/application/config/ConfigPlugin.php
@@ -39,8 +39,8 @@ function save_plugin_config($formData)
        throw new PluginConfigOrderException();
    }
-    $plugins = array();
+    $plugins = [];
-    $newEnabledPlugins = array();
+    $newEnabledPlugins = [];
    foreach ($formData as $key => $data) {
        if (startsWith($key, 'order')) {
            continue;
@@ -62,7 +62,7 @@ function save_plugin_config($formData)
        throw new PluginConfigOrderException();
    }
-    $finalPlugins = array();
+    $finalPlugins = [];
    // Make plugins order continuous.
    foreach ($plugins as $plugin) {
        $finalPlugins[] = $plugin;
@@ -81,7 +81,7 @@ function save_plugin_config($formData)
 */
 function validate_plugin_order($formData)
 {
-    $orders = array();
+    $orders = [];
    foreach ($formData as $key => $value) {
        // No duplicate order allowed.
        if (in_array($value, $orders, true)) {
diff --git a/application/config/exception/MissingFieldConfigException.php b/application/config/exception/MissingFieldConfigException.php
index 9e0a9359..a5f4356a 100644
--- a/application/config/exception/MissingFieldConfigException.php
+++ b/application/config/exception/MissingFieldConfigException.php
@@ -1,6 +1,5 @@
 <?php
 namespace Shaarli\Config\Exception;
 /**
diff --git a/application/config/exception/UnauthorizedConfigException.php b/application/config/exception/UnauthorizedConfigException.php
index 72311fae..b041c6e3 100644
--- a/application/config/exception/UnauthorizedConfigException.php
+++ b/application/config/exception/UnauthorizedConfigException.php
@@ -1,6 +1,5 @@
 <?php
 namespace Shaarli\Config\Exception;
 /**
diff --git a/application/container/ContainerBuilder.php b/application/container/ContainerBuilder.php
index c21d58dd..6d69a880 100644
--- a/application/container/ContainerBuilder.php
+++ b/application/container/ContainerBuilder.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace Shaarli\Container;
 use malkusch\lock\mutex\FlockMutex;
+use Psr\Log\LoggerInterface;
 use Shaarli\Bookmark\BookmarkFileService;
 use Shaarli\Bookmark\BookmarkServiceInterface;
 use Shaarli\Config\ConfigManager;
@@ -14,6 +15,7 @@ use Shaarli\Front\Controller\Visitor\ErrorController;
 use Shaarli\Front\Controller\Visitor\ErrorNotFoundController;
 use Shaarli\History;
 use Shaarli\Http\HttpAccess;
+use Shaarli\Http\MetadataRetriever;
 use Shaarli\Netscape\NetscapeBookmarkUtils;
 use Shaarli\Plugin\PluginManager;
 use Shaarli\Render\PageBuilder;
@@ -48,6 +50,12 @@ class ContainerBuilder
    /** @var LoginManager */
    protected $login;
+    /** @var PluginManager */
+    protected $pluginManager;
+    /** @var LoggerInterface */
+    protected $logger;
    /** @var string|null */
    protected $basePath = null;
@@ -55,12 +63,16 @@ class ContainerBuilder
        ConfigManager $conf,
        SessionManager $session,
        CookieManager $cookieManager,
-        LoginManager $login
+        LoginManager $login,
+        PluginManager $pluginManager,
+        LoggerInterface $logger
    ) {
        $this->conf = $conf;
        $this->session = $session;
        $this->login = $login;
        $this->cookieManager = $cookieManager;
+        $this->pluginManager = $pluginManager;
+        $this->logger = $logger;
    }
    public function build(): ShaarliContainer
@@ -71,11 +83,10 @@ class ContainerBuilder
        $container['sessionManager'] = $this->session;
        $container['cookieManager'] = $this->cookieManager;
        $container['loginManager'] = $this->login;
+        $container['pluginManager'] = $this->pluginManager;
+        $container['logger'] = $this->logger;
        $container['basePath'] = $this->basePath;
-        $container['plugins'] = function (ShaarliContainer $container): PluginManager {
-            return new PluginManager($container->conf);
-        };
        $container['history'] = function (ShaarliContainer $container): History {
            return new History($container->conf->get('resource.history'));
@@ -90,24 +101,21 @@ class ContainerBuilder
            );
        };
+        $container['metadataRetriever'] = function (ShaarliContainer $container): MetadataRetriever {
+            return new MetadataRetriever($container->conf, $container->httpAccess);
+        };
        $container['pageBuilder'] = function (ShaarliContainer $container): PageBuilder {
            return new PageBuilder(
                $container->conf,
                $container->sessionManager->getSession(),
+                $container->logger,
                $container->bookmarkService,
                $container->sessionManager->generateToken(),
                $container->loginManager->isLoggedIn()
            );
        };
-        $container['pluginManager'] = function (ShaarliContainer $container): PluginManager {
-            $pluginManager = new PluginManager($container->conf);
-            $pluginManager->load($container->conf->get('general.enabled_plugins'));
-            return $pluginManager;
-        };
        $container['formatterFactory'] = function (ShaarliContainer $container): FormatterFactory {
            return new FormatterFactory(
                $container->conf,
@@ -145,7 +153,7 @@ class ContainerBuilder
        $container['updater'] = function (ShaarliContainer $container): Updater {
            return new Updater(
-                UpdaterUtils::read_updates_file($container->conf->get('resource.updates')),
+                UpdaterUtils::readUpdatesFile($container->conf->get('resource.updates')),
                $container->bookmarkService,
                $container->conf,
                $container->loginManager->isLoggedIn()
diff --git a/application/container/ShaarliContainer.php b/application/container/ShaarliContainer.php
index 66e669aa..3e5bd252 100644
--- a/application/container/ShaarliContainer.php
+++ b/application/container/ShaarliContainer.php
@@ -4,12 +4,14 @@ declare(strict_types=1);
 namespace Shaarli\Container;
+use Psr\Log\LoggerInterface;
 use Shaarli\Bookmark\BookmarkServiceInterface;
 use Shaarli\Config\ConfigManager;
 use Shaarli\Feed\FeedBuilder;
 use Shaarli\Formatter\FormatterFactory;
 use Shaarli\History;
 use Shaarli\Http\HttpAccess;
+use Shaarli\Http\MetadataRetriever;
 use Shaarli\Netscape\NetscapeBookmarkUtils;
 use Shaarli\Plugin\PluginManager;
 use Shaarli\Render\PageBuilder;
@@ -35,6 +37,8 @@ use Slim\Container;
 * @property History                  $history
 * @property HttpAccess               $httpAccess
 * @property LoginManager             $loginManager
+ * @property LoggerInterface          $logger
+ * @property MetadataRetriever        $metadataRetriever
 * @property NetscapeBookmarkUtils    $netscapeBookmarkUtils
 * @property callable                 $notFoundHandler       Overrides default Slim exception display
 * @property PageBuilder              $pageBuilder
diff --git a/application/exceptions/IOException.php b/application/exceptions/IOException.php
index 2aa25e5c..c1a9ffbe 100644
--- a/application/exceptions/IOException.php
+++ b/application/exceptions/IOException.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Exceptions;
 use Exception;
diff --git a/application/feed/CachedPage.php b/application/feed/CachedPage.php
index d809bdd9..c23c200f 100644
--- a/application/feed/CachedPage.php
+++ b/application/feed/CachedPage.php
@@ -1,34 +1,43 @@
 <?php
+declare(strict_types=1);
 namespace Shaarli\Feed;
+use DatePeriod;
 /**
 * Simple cache system, mainly for the RSS/ATOM feeds
 */
 class CachedPage
 {
-    // Directory containing page caches
+    /** Directory containing page caches */
-    private $cacheDir;
+    protected $cacheDir;
+    /** Should this URL be cached (boolean)? */
+    protected $shouldBeCached;
-    // Should this URL be cached (boolean)?
+    /** Name of the cache file for this URL */
-    private $shouldBeCached;
+    protected $filename;
-    // Name of the cache file for this URL
+    /** @var DatePeriod|null Optionally specify a period of time for cache validity */
-    private $filename;
+    protected $validityPeriod;
    /**
     * Creates a new CachedPage
     *
-     * @param string $cacheDir       page cache directory
+     * @param string      $cacheDir       page cache directory
-     * @param string $url            page URL
+     * @param string      $url            page URL
-     * @param bool   $shouldBeCached whether this page needs to be cached
+     * @param bool        $shouldBeCached whether this page needs to be cached
+     * @param ?DatePeriod $validityPeriod Optionally specify a time limit on requested cache
     */
-    public function __construct($cacheDir, $url, $shouldBeCached)
+    public function __construct($cacheDir, $url, $shouldBeCached, ?DatePeriod $validityPeriod)
    {
        // TODO: check write access to the cache directory
        $this->cacheDir = $cacheDir;
        $this->filename = $this->cacheDir . '/' . sha1($url) . '.cache';
        $this->shouldBeCached = $shouldBeCached;
+        $this->validityPeriod = $validityPeriod;
    }
    /**
@@ -41,10 +50,20 @@ class CachedPage
        if (!$this->shouldBeCached) {
            return null;
        }
-        if (is_file($this->filename)) {
+        if (!is_file($this->filename)) {
-            return file_get_contents($this->filename);
+            return null;
+        }
+        if ($this->validityPeriod !== null) {
+            $cacheDate = \DateTime::createFromFormat('U', (string) filemtime($this->filename));
+            if (
+                $cacheDate < $this->validityPeriod->getStartDate()
+                || $cacheDate > $this->validityPeriod->getEndDate()
+            ) {
+                return null;
+            }
        }
-        return null;
+        return file_get_contents($this->filename);
    }
    /**
diff --git a/application/feed/FeedBuilder.php b/application/feed/FeedBuilder.php
index f70fce4f..ed62af26 100644
--- a/application/feed/FeedBuilder.php
+++ b/application/feed/FeedBuilder.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Feed;
 use DateTime;
@@ -107,14 +108,14 @@ class FeedBuilder
        $nblinksToDisplay = $this->getNbLinks(count($linksToDisplay), $userInput);
        // Can't use array_keys() because $link is a LinkDB instance and not a real array.
-        $keys = array();
+        $keys = [];
        foreach ($linksToDisplay as $key => $value) {
            $keys[] = $key;
        }
        $pageaddr = escape(index_url($this->serverInfo));
        $this->formatter->addContextData('index_url', $pageaddr);
-        $linkDisplayed = array();
+        $linkDisplayed = [];
        for ($i = 0; $i < $nblinksToDisplay && $i < count($keys); $i++) {
            $linkDisplayed[$keys[$i]] = $this->buildItem($feedType, $linksToDisplay[$keys[$i]], $pageaddr);
        }
@@ -176,9 +177,9 @@ class FeedBuilder
        $data = $this->formatter->format($link);
        $data['guid'] = rtrim($pageaddr, '/') . '/shaare/' . $data['shorturl'];
        if ($this->usePermalinks === true) {
-            $permalink = '<a href="'. $data['url'] .'" title="'. t('Direct link') .'">'. t('Direct link') .'</a>';
+            $permalink = '<a href="' . $data['url'] . '" title="' . t('Direct link') . '">' . t('Direct link') . '</a>';
        } else {
-            $permalink = '<a href="'. $data['guid'] .'" title="'. t('Permalink') .'">'. t('Permalink') .'</a>';
+            $permalink = '<a href="' . $data['guid'] . '" title="' . t('Permalink') . '">' . t('Permalink') . '</a>';
        }
        $data['description'] .= PHP_EOL . PHP_EOL . '<br>&#8212; ' . $permalink;
diff --git a/application/formatter/BookmarkDefaultFormatter.php b/application/formatter/BookmarkDefaultFormatter.php
index d58a5e39..7e0afafc 100644
--- a/application/formatter/BookmarkDefaultFormatter.php
+++ b/application/formatter/BookmarkDefaultFormatter.php
@@ -12,8 +12,8 @@ namespace Shaarli\Formatter;
 */
 class BookmarkDefaultFormatter extends BookmarkFormatter
 {
-    const SEARCH_HIGHLIGHT_OPEN = '|@@HIGHLIGHT';
+    protected const SEARCH_HIGHLIGHT_OPEN = '|@@HIGHLIGHT';
-    const SEARCH_HIGHLIGHT_CLOSE = 'HIGHLIGHT@@|';
+    protected const SEARCH_HIGHLIGHT_CLOSE = 'HIGHLIGHT@@|';
    /**
     * @inheritdoc
@@ -46,8 +46,13 @@ class BookmarkDefaultFormatter extends BookmarkFormatter
            $bookmark->getDescription() ?? '',
            $bookmark->getAdditionalContentEntry('search_highlight')['description'] ?? []
        );
+        $description = format_description(
+            escape($description),
+            $indexUrl,
+            $this->conf->get('formatter_settings.autolink', true)
+        );
-        return $this->replaceTokens(format_description(escape($description), $indexUrl));
+        return $this->replaceTokens($description);
    }
    /**
@@ -63,15 +68,16 @@ class BookmarkDefaultFormatter extends BookmarkFormatter
     */
    protected function formatTagListHtml($bookmark)
    {
+        $tagsSeparator = $this->conf->get('general.tags_separator', ' ');
        if (empty($bookmark->getAdditionalContentEntry('search_highlight')['tags'])) {
            return $this->formatTagList($bookmark);
        }
        $tags = $this->tokenizeSearchHighlightField(
-            $bookmark->getTagsString(),
+            $bookmark->getTagsString($tagsSeparator),
            $bookmark->getAdditionalContentEntry('search_highlight')['tags']
        );
-        $tags = $this->filterTagList(explode(' ', $tags));
+        $tags = $this->filterTagList(tags_str2array($tags, $tagsSeparator));
        $tags = escape($tags);
        $tags = $this->replaceTokensArray($tags);
@@ -83,7 +89,7 @@ class BookmarkDefaultFormatter extends BookmarkFormatter
     */
    protected function formatTagString($bookmark)
    {
-        return implode(' ', $this->formatTagList($bookmark));
+        return implode($this->conf->get('general.tags_separator'), $this->formatTagList($bookmark));
    }
    /**
diff --git a/application/formatter/BookmarkFormatter.php b/application/formatter/BookmarkFormatter.php
index e1b7f705..124ce78b 100644
--- a/application/formatter/BookmarkFormatter.php
+++ b/application/formatter/BookmarkFormatter.php
@@ -267,7 +267,7 @@ abstract class BookmarkFormatter
     */
    protected function formatTagString($bookmark)
    {
-        return implode(' ', $this->formatTagList($bookmark));
+        return implode($this->conf->get('general.tags_separator', ' '), $this->formatTagList($bookmark));
    }
    /**
@@ -351,6 +351,7 @@ abstract class BookmarkFormatter
    /**
     * Format tag list, e.g. remove private tags if the user is not logged in.
+     * TODO: this method is called multiple time to format tags, the result should be cached.
     *
     * @param array $tags
     *
diff --git a/application/formatter/BookmarkMarkdownFormatter.php b/application/formatter/BookmarkMarkdownFormatter.php
index f7714be9..ee4e8dca 100644
--- a/application/formatter/BookmarkMarkdownFormatter.php
+++ b/application/formatter/BookmarkMarkdownFormatter.php
@@ -16,7 +16,7 @@ class BookmarkMarkdownFormatter extends BookmarkDefaultFormatter
    /**
     * When this tag is present in a bookmark, its description should not be processed with Markdown
     */
-    const NO_MD_TAG = 'nomarkdown';
+    public const NO_MD_TAG = 'nomarkdown';
    /** @var \Parsedown instance */
    protected $parsedown;
@@ -71,7 +71,7 @@ class BookmarkMarkdownFormatter extends BookmarkDefaultFormatter
        $processedDescription = $this->replaceTokens($processedDescription);
        if (!empty($processedDescription)) {
-            $processedDescription = '<div class="markdown">'. $processedDescription . '</div>';
+            $processedDescription = '<div class="markdown">' . $processedDescription . '</div>';
        }
        return $processedDescription;
@@ -110,7 +110,7 @@ class BookmarkMarkdownFormatter extends BookmarkDefaultFormatter
            function ($match) use ($allowedProtocols, $indexUrl) {
                $link = startsWith($match[1], '?') || startsWith($match[1], '/') ? $indexUrl : '';
                $link .= whitelist_protocols($match[1], $allowedProtocols);
-                return ']('. $link.')';
+                return '](' . $link . ')';
            },
            $description
        );
@@ -137,7 +137,7 @@ class BookmarkMarkdownFormatter extends BookmarkDefaultFormatter
         * \p{Mn} - any non marking space (accents, umlauts, etc)
         */
        $regex = '/(^|\s)#([\p{Pc}\p{N}\p{L}\p{Mn}]+)/mui';
-        $replacement = '$1[#$2]('. $indexUrl .'./add-tag/$2)';
+        $replacement = '$1[#$2](' . $indexUrl . './add-tag/$2)';
        $descriptionLines = explode(PHP_EOL, $description);
        $descriptionOut = '';
@@ -178,17 +178,17 @@ class BookmarkMarkdownFormatter extends BookmarkDefaultFormatter
     */
    protected function sanitizeHtml($description)
    {
-        $escapeTags = array(
+        $escapeTags = [
            'script',
            'style',
            'link',
            'iframe',
            'frameset',
            'frame',
-        );
+        ];
        foreach ($escapeTags as $tag) {
            $description = preg_replace_callback(
-                '#<\s*'. $tag .'[^>]*>(.*</\s*'. $tag .'[^>]*>)?#is',
+                '#<\s*' . $tag . '[^>]*>(.*</\s*' . $tag . '[^>]*>)?#is',
                function ($match) {
                    return escape($match[0]);
                },
diff --git a/application/formatter/BookmarkRawFormatter.php b/application/formatter/BookmarkRawFormatter.php
index bc372273..4ff07cdf 100644
--- a/application/formatter/BookmarkRawFormatter.php
+++ b/application/formatter/BookmarkRawFormatter.php
@@ -10,4 +10,6 @@ namespace Shaarli\Formatter;
 *
 * @package Shaarli\Formatter
 */
-class BookmarkRawFormatter extends BookmarkFormatter {}
+class BookmarkRawFormatter extends BookmarkFormatter
+{
+}
diff --git a/application/formatter/FormatterFactory.php b/application/formatter/FormatterFactory.php
index a029579f..bb865aed 100644
--- a/application/formatter/FormatterFactory.php
+++ b/application/formatter/FormatterFactory.php
@@ -41,7 +41,7 @@ class FormatterFactory
    public function getFormatter(string $type = null): BookmarkFormatter
    {
        $type = $type ? $type : $this->conf->get('formatter', 'default');
-        $className = '\\Shaarli\\Formatter\\Bookmark'. ucfirst($type) .'Formatter';
+        $className = '\\Shaarli\\Formatter\\Bookmark' . ucfirst($type) . 'Formatter';
        if (!class_exists($className)) {
            $className = '\\Shaarli\\Formatter\\BookmarkDefaultFormatter';
        }
diff --git a/application/front/ShaarliMiddleware.php b/application/front/ShaarliMiddleware.php
index d1aa1399..164217f4 100644
--- a/application/front/ShaarliMiddleware.php
+++ b/application/front/ShaarliMiddleware.php
@@ -42,7 +42,8 @@ class ShaarliMiddleware
        $this->initBasePath($request);
        try {
-            if (!is_file($this->container->conf->getConfigFileExt())
+            if (
+                !is_file($this->container->conf->getConfigFileExt())
                && !in_array($next->getName(), ['displayInstall', 'saveInstall'], true)
            ) {
                return $response->withRedirect($this->container->basePath . '/install');
@@ -86,7 +87,8 @@ class ShaarliMiddleware
     */
    protected function checkOpenShaarli(Request $request, Response $response, callable $next): bool
    {
-        if (// if the user isn't logged in
+        if (
+// if the user isn't logged in
            !$this->container->loginManager->isLoggedIn()
            // and Shaarli doesn't have public content...
            && $this->container->conf->get('privacy.hide_public_links')
diff --git a/application/front/controller/admin/ConfigureController.php b/application/front/controller/admin/ConfigureController.php
index 0ed7ad81..dc421661 100644
--- a/application/front/controller/admin/ConfigureController.php
+++ b/application/front/controller/admin/ConfigureController.php
@@ -51,7 +51,10 @@ class ConfigureController extends ShaarliAdminController
        $this->assignView('languages', Languages::getAvailableLanguages());
        $this->assignView('gd_enabled', extension_loaded('gd'));
        $this->assignView('thumbnails_mode', $this->container->conf->get('thumbnails.mode', Thumbnailer::MODE_NONE));
-        $this->assignView('pagetitle', t('Configure') .' - '. $this->container->conf->get('general.title', 'Shaarli'));
+        $this->assignView(
+            'pagetitle',
+            t('Configure') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
+        );
        return $response->write($this->render(TemplatePage::CONFIGURE));
    }
@@ -95,12 +98,15 @@ class ConfigureController extends ShaarliAdminController
        }
        $thumbnailsMode = extension_loaded('gd') ? $request->getParam('enableThumbnails') : Thumbnailer::MODE_NONE;
-        if ($thumbnailsMode !== Thumbnailer::MODE_NONE
+        if (
+            $thumbnailsMode !== Thumbnailer::MODE_NONE
            && $thumbnailsMode !== $this->container->conf->get('thumbnails.mode', Thumbnailer::MODE_NONE)
        ) {
            $this->saveWarningMessage(
                t('You have enabled or changed thumbnails mode.') .
-                '<a href="'. $this->container->basePath .'/admin/thumbnails">' . t('Please synchronize them.') .'</a>'
+                '<a href="' . $this->container->basePath . '/admin/thumbnails">' .
+                    t('Please synchronize them.') .
+                '</a>'
            );
        }
        $this->container->conf->set('thumbnails.mode', $thumbnailsMode);
diff --git a/application/front/controller/admin/ExportController.php b/application/front/controller/admin/ExportController.php
index 2be957fa..f01d7e9b 100644
--- a/application/front/controller/admin/ExportController.php
+++ b/application/front/controller/admin/ExportController.php
@@ -23,7 +23,7 @@ class ExportController extends ShaarliAdminController
     */
    public function index(Request $request, Response $response): Response
    {
-        $this->assignView('pagetitle', t('Export') .' - '. $this->container->conf->get('general.title', 'Shaarli'));
+        $this->assignView('pagetitle', t('Export') . ' - ' . $this->container->conf->get('general.title', 'Shaarli'));
        return $response->write($this->render(TemplatePage::EXPORT));
    }
@@ -68,7 +68,7 @@ class ExportController extends ShaarliAdminController
        $response = $response->withHeader('Content-Type', 'text/html; charset=utf-8');
        $response = $response->withHeader(
            'Content-disposition',
-            'attachment; filename=bookmarks_'.$selection.'_'.$now->format(Bookmark::LINK_DATE_FORMAT).'.html'
+            'attachment; filename=bookmarks_' . $selection . '_' . $now->format(Bookmark::LINK_DATE_FORMAT) . '.html'
        );
        $this->assignView('date', $now->format(DateTime::RFC822));
diff --git a/application/front/controller/admin/ImportController.php b/application/front/controller/admin/ImportController.php
index 758d5ef9..c2ad6a09 100644
--- a/application/front/controller/admin/ImportController.php
+++ b/application/front/controller/admin/ImportController.php
@@ -38,7 +38,7 @@ class ImportController extends ShaarliAdminController
                true
            )
        );
-        $this->assignView('pagetitle', t('Import') .' - '. $this->container->conf->get('general.title', 'Shaarli'));
+        $this->assignView('pagetitle', t('Import') . ' - ' . $this->container->conf->get('general.title', 'Shaarli'));
        return $response->write($this->render(TemplatePage::IMPORT));
    }
@@ -64,7 +64,7 @@ class ImportController extends ShaarliAdminController
            $msg = sprintf(
                t(
                    'The file you are trying to upload is probably bigger than what this webserver can accept'
-                    .' (%s). Please upload in smaller chunks.'
+                    . ' (%s). Please upload in smaller chunks.'
                ),
                get_max_upload_size(ini_get('post_max_size'), ini_get('upload_max_filesize'))
            );
diff --git a/application/front/controller/admin/ManageShaareController.php b/application/front/controller/admin/ManageShaareController.php
deleted file mode 100644
index bb083486..00000000
--- a/application/front/controller/admin/ManageShaareController.php
+++ /dev/null
@@ -1,371 +0,0 @@
-<?php
-declare(strict_types=1);
-namespace Shaarli\Front\Controller\Admin;
-use Shaarli\Bookmark\Bookmark;
-use Shaarli\Bookmark\Exception\BookmarkNotFoundException;
-use Shaarli\Formatter\BookmarkMarkdownFormatter;
-use Shaarli\Render\TemplatePage;
-use Shaarli\Thumbnailer;
-use Slim\Http\Request;
-use Slim\Http\Response;
-/**
- * Class PostBookmarkController
- *
- * Slim controller used to handle Shaarli create or edit bookmarks.
- */
-class ManageShaareController extends ShaarliAdminController
-{
-    /**
-     * GET /admin/add-shaare - Displays the form used to create a new bookmark from an URL
-     */
-    public function addShaare(Request $request, Response $response): Response
-    {
-        $this->assignView(
-            'pagetitle',
-            t('Shaare a new link') .' - '. $this->container->conf->get('general.title', 'Shaarli')
-        );
-        return $response->write($this->render(TemplatePage::ADDLINK));
-    }
-    /**
-     * GET /admin/shaare - Displays the bookmark form for creation.
-     *                     Note that if the URL is found in existing bookmarks, then it will be in edit mode.
-     */
-    public function displayCreateForm(Request $request, Response $response): Response
-    {
-        $url = cleanup_url($request->getParam('post'));
-        $linkIsNew = false;
-        // Check if URL is not already in database (in this case, we will edit the existing link)
-        $bookmark = $this->container->bookmarkService->findByUrl($url);
-        if (null === $bookmark) {
-            $linkIsNew = true;
-            // Get shaare data if it was provided in URL (e.g.: by the bookmarklet).
-            $title = $request->getParam('title');
-            $description = $request->getParam('description');
-            $tags = $request->getParam('tags');
-            $private = filter_var($request->getParam('private'), FILTER_VALIDATE_BOOLEAN);
-            // If this is an HTTP(S) link, we try go get the page to extract
-            // the title (otherwise we will to straight to the edit form.)
-            if (empty($title) && strpos(get_url_scheme($url) ?: '', 'http') !== false) {
-                $retrieveDescription = $this->container->conf->get('general.retrieve_description');
-                // Short timeout to keep the application responsive
-                // The callback will fill $charset and $title with data from the downloaded page.
-                $this->container->httpAccess->getHttpResponse(
-                    $url,
-                    $this->container->conf->get('general.download_timeout', 30),
-                    $this->container->conf->get('general.download_max_size', 4194304),
-                    $this->container->httpAccess->getCurlDownloadCallback(
-                        $charset,
-                        $title,
-                        $description,
-                        $tags,
-                        $retrieveDescription
-                    )
-                );
-                if (! empty($title) && strtolower($charset) !== 'utf-8' && mb_check_encoding($charset)) {
-                    $title = mb_convert_encoding($title, 'utf-8', $charset);
-                }
-            }
-            if (empty($url) && empty($title)) {
-                $title = $this->container->conf->get('general.default_note_title', t('Note: '));
-            }
-            $link = [
-                'title' => $title,
-                'url' => $url ?? '',
-                'description' => $description ?? '',
-                'tags' => $tags ?? '',
-                'private' => $private,
-            ];
-        } else {
-            $formatter = $this->container->formatterFactory->getFormatter('raw');
-            $link = $formatter->format($bookmark);
-        }
-        return $this->displayForm($link, $linkIsNew, $request, $response);
-    }
-    /**
-     * GET /admin/shaare/{id} - Displays the bookmark form in edition mode.
-     */
-    public function displayEditForm(Request $request, Response $response, array $args): Response
-    {
-        $id = $args['id'] ?? '';
-        try {
-            if (false === ctype_digit($id)) {
-                throw new BookmarkNotFoundException();
-            }
-            $bookmark = $this->container->bookmarkService->get((int) $id);  // Read database
-        } catch (BookmarkNotFoundException $e) {
-            $this->saveErrorMessage(sprintf(
-                t('Bookmark with identifier %s could not be found.'),
-                $id
-            ));
-            return $this->redirect($response, '/');
-        }
-        $formatter = $this->container->formatterFactory->getFormatter('raw');
-        $link = $formatter->format($bookmark);
-        return $this->displayForm($link, false, $request, $response);
-    }
-    /**
-     * POST /admin/shaare
-     */
-    public function save(Request $request, Response $response): Response
-    {
-        $this->checkToken($request);
-        // lf_id should only be present if the link exists.
-        $id = $request->getParam('lf_id') !== null ? intval(escape($request->getParam('lf_id'))) : null;
-        if (null !== $id && true === $this->container->bookmarkService->exists($id)) {
-            // Edit
-            $bookmark = $this->container->bookmarkService->get($id);
-        } else {
-            // New link
-            $bookmark = new Bookmark();
-        }
-        $bookmark->setTitle($request->getParam('lf_title'));
-        $bookmark->setDescription($request->getParam('lf_description'));
-        $bookmark->setUrl($request->getParam('lf_url'), $this->container->conf->get('security.allowed_protocols', []));
-        $bookmark->setPrivate(filter_var($request->getParam('lf_private'), FILTER_VALIDATE_BOOLEAN));
-        $bookmark->setTagsString($request->getParam('lf_tags'));
-        if ($this->container->conf->get('thumbnails.mode', Thumbnailer::MODE_NONE) !== Thumbnailer::MODE_NONE
-            && false === $bookmark->isNote()
-        ) {
-            $bookmark->setThumbnail($this->container->thumbnailer->get($bookmark->getUrl()));
-        }
-        $this->container->bookmarkService->addOrSet($bookmark, false);
-        // To preserve backward compatibility with 3rd parties, plugins still use arrays
-        $formatter = $this->container->formatterFactory->getFormatter('raw');
-        $data = $formatter->format($bookmark);
-        $this->executePageHooks('save_link', $data);
-        $bookmark->fromArray($data);
-        $this->container->bookmarkService->set($bookmark);
-        // If we are called from the bookmarklet, we must close the popup:
-        if ($request->getParam('source') === 'bookmarklet') {
-            return $response->write('<script>self.close();</script>');
-        }
-        if (!empty($request->getParam('returnurl'))) {
-            $this->container->environment['HTTP_REFERER'] = escape($request->getParam('returnurl'));
-        }
-        return $this->redirectFromReferer(
-            $request,
-            $response,
-            ['/admin/add-shaare', '/admin/shaare'], ['addlink', 'post', 'edit_link'],
-            $bookmark->getShortUrl()
-        );
-    }
-    /**
-     * GET /admin/shaare/delete - Delete one or multiple bookmarks (depending on `id` query parameter).
-     */
-    public function deleteBookmark(Request $request, Response $response): Response
-    {
-        $this->checkToken($request);
-        $ids = escape(trim($request->getParam('id') ?? ''));
-        if (empty($ids) || strpos($ids, ' ') !== false) {
-            // multiple, space-separated ids provided
-            $ids = array_values(array_filter(preg_split('/\s+/', $ids), 'ctype_digit'));
-        } else {
-            $ids = [$ids];
-        }
-        // assert at least one id is given
-        if (0 === count($ids)) {
-            $this->saveErrorMessage(t('Invalid bookmark ID provided.'));
-            return $this->redirectFromReferer($request, $response, [], ['delete-shaare']);
-        }
-        $formatter = $this->container->formatterFactory->getFormatter('raw');
-        $count = 0;
-        foreach ($ids as $id) {
-            try {
-                $bookmark = $this->container->bookmarkService->get((int) $id);
-            } catch (BookmarkNotFoundException $e) {
-                $this->saveErrorMessage(sprintf(
-                    t('Bookmark with identifier %s could not be found.'),
-                    $id
-                ));
-                continue;
-            }
-            $data = $formatter->format($bookmark);
-            $this->executePageHooks('delete_link', $data);
-            $this->container->bookmarkService->remove($bookmark, false);
-            ++ $count;
-        }
-        if ($count > 0) {
-            $this->container->bookmarkService->save();
-        }
-        // If we are called from the bookmarklet, we must close the popup:
-        if ($request->getParam('source') === 'bookmarklet') {
-            return $response->write('<script>self.close();</script>');
-        }
-        // Don't redirect to where we were previously because the datastore has changed.
-        return $this->redirect($response, '/');
-    }
-    /**
-     * GET /admin/shaare/visibility
-     *
-     * Change visibility (public/private) of one or multiple bookmarks (depending on `id` query parameter).
-     */
-    public function changeVisibility(Request $request, Response $response): Response
-    {
-        $this->checkToken($request);
-        $ids = trim(escape($request->getParam('id') ?? ''));
-        if (empty($ids) || strpos($ids, ' ') !== false) {
-            // multiple, space-separated ids provided
-            $ids = array_values(array_filter(preg_split('/\s+/', $ids), 'ctype_digit'));
-        } else {
-            // only a single id provided
-            $ids = [$ids];
-        }
-        // assert at least one id is given
-        if (0 === count($ids)) {
-            $this->saveErrorMessage(t('Invalid bookmark ID provided.'));
-            return $this->redirectFromReferer($request, $response, [], ['change_visibility']);
-        }
-        // assert that the visibility is valid
-        $visibility = $request->getParam('newVisibility');
-        if (null === $visibility || false === in_array($visibility, ['public', 'private'], true)) {
-            $this->saveErrorMessage(t('Invalid visibility provided.'));
-            return $this->redirectFromReferer($request, $response, [], ['change_visibility']);
-        } else {
-            $isPrivate = $visibility === 'private';
-        }
-        $formatter = $this->container->formatterFactory->getFormatter('raw');
-        $count = 0;
-        foreach ($ids as $id) {
-            try {
-                $bookmark = $this->container->bookmarkService->get((int) $id);
-            } catch (BookmarkNotFoundException $e) {
-                $this->saveErrorMessage(sprintf(
-                    t('Bookmark with identifier %s could not be found.'),
-                    $id
-                ));
-                continue;
-            }
-            $bookmark->setPrivate($isPrivate);
-            // To preserve backward compatibility with 3rd parties, plugins still use arrays
-            $data = $formatter->format($bookmark);
-            $this->executePageHooks('save_link', $data);
-            $bookmark->fromArray($data);
-            $this->container->bookmarkService->set($bookmark, false);
-            ++$count;
-        }
-        if ($count > 0) {
-            $this->container->bookmarkService->save();
-        }
-        return $this->redirectFromReferer($request, $response, ['/visibility'], ['change_visibility']);
-    }
-    /**
-     * GET /admin/shaare/{id}/pin - Pin or unpin a bookmark.
-     */
-    public function pinBookmark(Request $request, Response $response, array $args): Response
-    {
-        $this->checkToken($request);
-        $id = $args['id'] ?? '';
-        try {
-            if (false === ctype_digit($id)) {
-                throw new BookmarkNotFoundException();
-            }
-            $bookmark = $this->container->bookmarkService->get((int) $id);  // Read database
-        } catch (BookmarkNotFoundException $e) {
-            $this->saveErrorMessage(sprintf(
-                t('Bookmark with identifier %s could not be found.'),
-                $id
-            ));
-            return $this->redirectFromReferer($request, $response, ['/pin'], ['pin']);
-        }
-        $formatter = $this->container->formatterFactory->getFormatter('raw');
-        $bookmark->setSticky(!$bookmark->isSticky());
-        // To preserve backward compatibility with 3rd parties, plugins still use arrays
-        $data = $formatter->format($bookmark);
-        $this->executePageHooks('save_link', $data);
-        $bookmark->fromArray($data);
-        $this->container->bookmarkService->set($bookmark);
-        return $this->redirectFromReferer($request, $response, ['/pin'], ['pin']);
-    }
-    /**
-     * Helper function used to display the shaare form whether it's a new or existing bookmark.
-     *
-     * @param array $link data used in template, either from parameters or from the data store
-     */
-    protected function displayForm(array $link, bool $isNew, Request $request, Response $response): Response
-    {
-        $tags = $this->container->bookmarkService->bookmarksCountPerTag();
-        if ($this->container->conf->get('formatter') === 'markdown') {
-            $tags[BookmarkMarkdownFormatter::NO_MD_TAG] = 1;
-        }
-        $data = escape([
-            'link' => $link,
-            'link_is_new' => $isNew,
-            'http_referer' => $this->container->environment['HTTP_REFERER'] ?? '',
-            'source' => $request->getParam('source') ?? '',
-            'tags' => $tags,
-            'default_private_links' => $this->container->conf->get('privacy.default_private_links', false),
-        ]);
-        $this->executePageHooks('render_editlink', $data, TemplatePage::EDIT_LINK);
-        foreach ($data as $key => $value) {
-            $this->assignView($key, $value);
-        }
-        $editLabel = false === $isNew ? t('Edit') .' ' : '';
-        $this->assignView(
-            'pagetitle',
-            $editLabel . t('Shaare') .' - '. $this->container->conf->get('general.title', 'Shaarli')
-        );
-        return $response->write($this->render(TemplatePage::EDIT_LINK));
-    }
-}
diff --git a/application/front/controller/admin/ManageTagController.php b/application/front/controller/admin/ManageTagController.php
index 2065c3e2..8675a0c5 100644
--- a/application/front/controller/admin/ManageTagController.php
+++ b/application/front/controller/admin/ManageTagController.php
@@ -24,9 +24,15 @@ class ManageTagController extends ShaarliAdminController
        $fromTag = $request->getParam('fromtag') ?? '';
        $this->assignView('fromtag', escape($fromTag));
+        $separator = escape($this->container->conf->get('general.tags_separator', ' '));
+        if ($separator === ' ') {
+            $separator = '&nbsp;';
+            $this->assignView('tags_separator_desc', t('whitespace'));
+        }
+        $this->assignView('tags_separator', $separator);
        $this->assignView(
            'pagetitle',
-            t('Manage tags') .' - '. $this->container->conf->get('general.title', 'Shaarli')
+            t('Manage tags') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
        );
        return $response->write($this->render(TemplatePage::CHANGE_TAG));
@@ -81,8 +87,35 @@ class ManageTagController extends ShaarliAdminController
        $this->saveSuccessMessage($alert);
-        $redirect = true === $isDelete ? '/admin/tags' : '/?searchtags='. urlencode($toTag);
+        $redirect = true === $isDelete ? '/admin/tags' : '/?searchtags=' . urlencode($toTag);
        return $this->redirect($response, $redirect);
    }
+    /**
+     * POST /admin/tags/change-separator - Change tag separator
+     */
+    public function changeSeparator(Request $request, Response $response): Response
+    {
+        $this->checkToken($request);
+        $reservedCharacters = ['-', '.', '*'];
+        $newSeparator = $request->getParam('separator');
+        if ($newSeparator === null || mb_strlen($newSeparator) !== 1) {
+            $this->saveErrorMessage(t('Tags separator must be a single character.'));
+        } elseif (in_array($newSeparator, $reservedCharacters, true)) {
+            $reservedCharacters = implode(' ', array_map(function (string $character) {
+                return '<code>' . $character . '</code>';
+            }, $reservedCharacters));
+            $this->saveErrorMessage(
+                t('These characters are reserved and can\'t be used as tags separator: ') . $reservedCharacters
+            );
+        } else {
+            $this->container->conf->set('general.tags_separator', $newSeparator, true, true);
+            $this->saveSuccessMessage('Your tags separator setting has been updated!');
+        }
+        return $this->redirect($response, '/admin/tags');
+    }
 }
diff --git a/application/front/controller/admin/MetadataController.php b/application/front/controller/admin/MetadataController.php
new file mode 100644
index 00000000..ff845944
--- /dev/null
+++ b/application/front/controller/admin/MetadataController.php
@@ -0,0 +1,29 @@
+<?php
+declare(strict_types=1);
+namespace Shaarli\Front\Controller\Admin;
+use Slim\Http\Request;
+use Slim\Http\Response;
+/**
+ * Controller used to retrieve/update bookmark's metadata.
+ */
+class MetadataController extends ShaarliAdminController
+{
+    /**
+     * GET /admin/metadata/{url} - Attempt to retrieve the bookmark title from provided URL.
+     */
+    public function ajaxRetrieveTitle(Request $request, Response $response): Response
+    {
+        $url = $request->getParam('url');
+        // Only try to extract metadata from URL with HTTP(s) scheme
+        if (!empty($url) && strpos(get_url_scheme($url) ?: '', 'http') !== false) {
+            return $response->withJson($this->container->metadataRetriever->retrieve($url));
+        }
+        return $response->withJson([]);
+    }
+}
diff --git a/application/front/controller/admin/PasswordController.php b/application/front/controller/admin/PasswordController.php
index 5ec0d24b..4aaf1f82 100644
--- a/application/front/controller/admin/PasswordController.php
+++ b/application/front/controller/admin/PasswordController.php
@@ -25,7 +25,7 @@ class PasswordController extends ShaarliAdminController
        $this->assignView(
            'pagetitle',
-            t('Change password') .' - '. $this->container->conf->get('general.title', 'Shaarli')
+            t('Change password') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
        );
    }
@@ -78,7 +78,7 @@ class PasswordController extends ShaarliAdminController
        // Save new password
        // Salt renders rainbow-tables attacks useless.
-        $this->container->conf->set('credentials.salt', sha1(uniqid('', true) .'_'. mt_rand()));
+        $this->container->conf->set('credentials.salt', sha1(uniqid('', true) . '_' . mt_rand()));
        $this->container->conf->set(
            'credentials.hash',
            sha1(
diff --git a/application/front/controller/admin/PluginsController.php b/application/front/controller/admin/PluginsController.php
index 8e059681..ae47c1af 100644
--- a/application/front/controller/admin/PluginsController.php
+++ b/application/front/controller/admin/PluginsController.php
@@ -42,7 +42,7 @@ class PluginsController extends ShaarliAdminController
        $this->assignView('disabledPlugins', $disabledPlugins);
        $this->assignView(
            'pagetitle',
-            t('Plugin Administration') .' - '. $this->container->conf->get('general.title', 'Shaarli')
+            t('Plugin Administration') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
        );
        return $response->write($this->render(TemplatePage::PLUGINS_ADMIN));
@@ -64,7 +64,7 @@ class PluginsController extends ShaarliAdminController
                unset($parameters['parameters_form']);
                unset($parameters['token']);
                foreach ($parameters as $param => $value) {
-                    $this->container->conf->set('plugins.'. $param, escape($value));
+                    $this->container->conf->set('plugins.' . $param, escape($value));
                }
            } else {
                $this->container->conf->set('general.enabled_plugins', save_plugin_config($parameters));
diff --git a/application/front/controller/admin/ServerController.php b/application/front/controller/admin/ServerController.php
new file mode 100644
index 00000000..4b74f4a9
--- /dev/null
+++ b/application/front/controller/admin/ServerController.php
@@ -0,0 +1,101 @@
+<?php
+declare(strict_types=1);
+namespace Shaarli\Front\Controller\Admin;
+use Shaarli\Helper\ApplicationUtils;
+use Shaarli\Helper\FileUtils;
+use Slim\Http\Request;
+use Slim\Http\Response;
+/**
+ * Slim controller used to handle Server administration page, and actions.
+ */
+class ServerController extends ShaarliAdminController
+{
+    /** @var string Cache type - main - by default pagecache/ and tmp/ */
+    protected const CACHE_MAIN = 'main';
+    /** @var string Cache type - thumbnails - by default cache/ */
+    protected const CACHE_THUMB = 'thumbnails';
+    /**
+     * GET /admin/server - Display page Server administration
+     */
+    public function index(Request $request, Response $response): Response
+    {
+        $releaseUrl = ApplicationUtils::$GITHUB_URL . '/releases/';
+        if ($this->container->conf->get('updates.check_updates', true)) {
+            $latestVersion = 'v' . ApplicationUtils::getVersion(
+                ApplicationUtils::$GIT_RAW_URL . '/latest/' . ApplicationUtils::$VERSION_FILE
+            );
+            $releaseUrl .= 'tag/' . $latestVersion;
+        } else {
+            $latestVersion = t('Check disabled');
+        }
+        $currentVersion = ApplicationUtils::getVersion('./shaarli_version.php');
+        $currentVersion = $currentVersion === 'dev' ? $currentVersion : 'v' . $currentVersion;
+        $phpEol = new \DateTimeImmutable(ApplicationUtils::getPhpEol(PHP_VERSION));
+        $permissions = array_merge(
+            ApplicationUtils::checkResourcePermissions($this->container->conf),
+            ApplicationUtils::checkDatastoreMutex()
+        );
+        $this->assignView('php_version', PHP_VERSION);
+        $this->assignView('php_eol', format_date($phpEol, false));
+        $this->assignView('php_has_reached_eol', $phpEol < new \DateTimeImmutable());
+        $this->assignView('php_extensions', ApplicationUtils::getPhpExtensionsRequirement());
+        $this->assignView('permissions', $permissions);
+        $this->assignView('release_url', $releaseUrl);
+        $this->assignView('latest_version', $latestVersion);
+        $this->assignView('current_version', $currentVersion);
+        $this->assignView('thumbnails_mode', $this->container->conf->get('thumbnails.mode'));
+        $this->assignView('index_url', index_url($this->container->environment));
+        $this->assignView('client_ip', client_ip_id($this->container->environment));
+        $this->assignView('trusted_proxies', $this->container->conf->get('security.trusted_proxies', []));
+        $this->assignView(
+            'pagetitle',
+            t('Server administration') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
+        );
+        return $response->write($this->render('server'));
+    }
+    /**
+     * GET /admin/clear-cache?type={$type} - Action to trigger cache folder clearing (either main or thumbnails).
+     */
+    public function clearCache(Request $request, Response $response): Response
+    {
+        $exclude = ['.htaccess'];
+        if ($request->getQueryParam('type') === static::CACHE_THUMB) {
+            $folders = [$this->container->conf->get('resource.thumbnails_cache')];
+            $this->saveWarningMessage(
+                t('Thumbnails cache has been cleared.') . ' ' .
+                '<a href="' . $this->container->basePath . '/admin/thumbnails">' .
+                    t('Please synchronize them.') .
+                '</a>'
+            );
+        } else {
+            $folders = [
+                $this->container->conf->get('resource.page_cache'),
+                $this->container->conf->get('resource.raintpl_tmp'),
+            ];
+            $this->saveSuccessMessage(t('Shaarli\'s cache folder has been cleared!'));
+        }
+        // Make sure that we don't delete root cache folder
+        $folders = array_map('realpath', array_values(array_filter(array_map('trim', $folders))));
+        foreach ($folders as $folder) {
+            FileUtils::clearFolder($folder, false, $exclude);
+        }
+        return $this->redirect($response, '/admin/server');
+    }
+}
diff --git a/application/front/controller/admin/SessionFilterController.php b/application/front/controller/admin/SessionFilterController.php
index d9a7a2e0..0917b6d2 100644
--- a/application/front/controller/admin/SessionFilterController.php
+++ b/application/front/controller/admin/SessionFilterController.php
@@ -45,6 +45,4 @@ class SessionFilterController extends ShaarliAdminController
        return $this->redirectFromReferer($request, $response, ['visibility']);
    }
 }
diff --git a/application/front/controller/admin/ShaareAddController.php b/application/front/controller/admin/ShaareAddController.php
new file mode 100644
index 00000000..ab8e7f40
--- /dev/null
+++ b/application/front/controller/admin/ShaareAddController.php
@@ -0,0 +1,34 @@
+<?php
+declare(strict_types=1);
+namespace Shaarli\Front\Controller\Admin;
+use Shaarli\Formatter\BookmarkMarkdownFormatter;
+use Shaarli\Render\TemplatePage;
+use Slim\Http\Request;
+use Slim\Http\Response;
+class ShaareAddController extends ShaarliAdminController
+{
+    /**
+     * GET /admin/add-shaare - Displays the form used to create a new bookmark from an URL
+     */
+    public function addShaare(Request $request, Response $response): Response
+    {
+        $tags = $this->container->bookmarkService->bookmarksCountPerTag();
+        if ($this->container->conf->get('formatter') === 'markdown') {
+            $tags[BookmarkMarkdownFormatter::NO_MD_TAG] = 1;
+        }
+        $this->assignView(
+            'pagetitle',
+            t('Shaare a new link') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
+        );
+        $this->assignView('tags', $tags);
+        $this->assignView('default_private_links', $this->container->conf->get('privacy.default_private_links', false));
+        $this->assignView('async_metadata', $this->container->conf->get('general.enable_async_metadata', true));
+        return $response->write($this->render(TemplatePage::ADDLINK));
+    }
+}
diff --git a/application/front/controller/admin/ShaareManageController.php b/application/front/controller/admin/ShaareManageController.php
new file mode 100644
index 00000000..35837baa
--- /dev/null
+++ b/application/front/controller/admin/ShaareManageController.php
@@ -0,0 +1,202 @@
+<?php
+declare(strict_types=1);
+namespace Shaarli\Front\Controller\Admin;
+use Shaarli\Bookmark\Exception\BookmarkNotFoundException;
+use Slim\Http\Request;
+use Slim\Http\Response;
+/**
+ * Class PostBookmarkController
+ *
+ * Slim controller used to handle Shaarli create or edit bookmarks.
+ */
+class ShaareManageController extends ShaarliAdminController
+{
+    /**
+     * GET /admin/shaare/delete - Delete one or multiple bookmarks (depending on `id` query parameter).
+     */
+    public function deleteBookmark(Request $request, Response $response): Response
+    {
+        $this->checkToken($request);
+        $ids = escape(trim($request->getParam('id') ?? ''));
+        if (empty($ids) || strpos($ids, ' ') !== false) {
+            // multiple, space-separated ids provided
+            $ids = array_values(array_filter(preg_split('/\s+/', $ids), 'ctype_digit'));
+        } else {
+            $ids = [$ids];
+        }
+        // assert at least one id is given
+        if (0 === count($ids)) {
+            $this->saveErrorMessage(t('Invalid bookmark ID provided.'));
+            return $this->redirectFromReferer($request, $response, [], ['delete-shaare']);
+        }
+        $formatter = $this->container->formatterFactory->getFormatter('raw');
+        $count = 0;
+        foreach ($ids as $id) {
+            try {
+                $bookmark = $this->container->bookmarkService->get((int) $id);
+            } catch (BookmarkNotFoundException $e) {
+                $this->saveErrorMessage(sprintf(
+                    t('Bookmark with identifier %s could not be found.'),
+                    $id
+                ));
+                continue;
+            }
+            $data = $formatter->format($bookmark);
+            $this->executePageHooks('delete_link', $data);
+            $this->container->bookmarkService->remove($bookmark, false);
+            ++$count;
+        }
+        if ($count > 0) {
+            $this->container->bookmarkService->save();
+        }
+        // If we are called from the bookmarklet, we must close the popup:
+        if ($request->getParam('source') === 'bookmarklet') {
+            return $response->write('<script>self.close();</script>');
+        }
+        // Don't redirect to permalink after deletion.
+        return $this->redirectFromReferer($request, $response, ['shaare/']);
+    }
+    /**
+     * GET /admin/shaare/visibility
+     *
+     * Change visibility (public/private) of one or multiple bookmarks (depending on `id` query parameter).
+     */
+    public function changeVisibility(Request $request, Response $response): Response
+    {
+        $this->checkToken($request);
+        $ids = trim(escape($request->getParam('id') ?? ''));
+        if (empty($ids) || strpos($ids, ' ') !== false) {
+            // multiple, space-separated ids provided
+            $ids = array_values(array_filter(preg_split('/\s+/', $ids), 'ctype_digit'));
+        } else {
+            // only a single id provided
+            $ids = [$ids];
+        }
+        // assert at least one id is given
+        if (0 === count($ids)) {
+            $this->saveErrorMessage(t('Invalid bookmark ID provided.'));
+            return $this->redirectFromReferer($request, $response, [], ['change_visibility']);
+        }
+        // assert that the visibility is valid
+        $visibility = $request->getParam('newVisibility');
+        if (null === $visibility || false === in_array($visibility, ['public', 'private'], true)) {
+            $this->saveErrorMessage(t('Invalid visibility provided.'));
+            return $this->redirectFromReferer($request, $response, [], ['change_visibility']);
+        } else {
+            $isPrivate = $visibility === 'private';
+        }
+        $formatter = $this->container->formatterFactory->getFormatter('raw');
+        $count = 0;
+        foreach ($ids as $id) {
+            try {
+                $bookmark = $this->container->bookmarkService->get((int) $id);
+            } catch (BookmarkNotFoundException $e) {
+                $this->saveErrorMessage(sprintf(
+                    t('Bookmark with identifier %s could not be found.'),
+                    $id
+                ));
+                continue;
+            }
+            $bookmark->setPrivate($isPrivate);
+            // To preserve backward compatibility with 3rd parties, plugins still use arrays
+            $data = $formatter->format($bookmark);
+            $this->executePageHooks('save_link', $data);
+            $bookmark->fromArray($data, $this->container->conf->get('general.tags_separator', ' '));
+            $this->container->bookmarkService->set($bookmark, false);
+            ++$count;
+        }
+        if ($count > 0) {
+            $this->container->bookmarkService->save();
+        }
+        return $this->redirectFromReferer($request, $response, ['/visibility'], ['change_visibility']);
+    }
+    /**
+     * GET /admin/shaare/{id}/pin - Pin or unpin a bookmark.
+     */
+    public function pinBookmark(Request $request, Response $response, array $args): Response
+    {
+        $this->checkToken($request);
+        $id = $args['id'] ?? '';
+        try {
+            if (false === ctype_digit($id)) {
+                throw new BookmarkNotFoundException();
+            }
+            $bookmark = $this->container->bookmarkService->get((int) $id);  // Read database
+        } catch (BookmarkNotFoundException $e) {
+            $this->saveErrorMessage(sprintf(
+                t('Bookmark with identifier %s could not be found.'),
+                $id
+            ));
+            return $this->redirectFromReferer($request, $response, ['/pin'], ['pin']);
+        }
+        $formatter = $this->container->formatterFactory->getFormatter('raw');
+        $bookmark->setSticky(!$bookmark->isSticky());
+        // To preserve backward compatibility with 3rd parties, plugins still use arrays
+        $data = $formatter->format($bookmark);
+        $this->executePageHooks('save_link', $data);
+        $bookmark->fromArray($data, $this->container->conf->get('general.tags_separator', ' '));
+        $this->container->bookmarkService->set($bookmark);
+        return $this->redirectFromReferer($request, $response, ['/pin'], ['pin']);
+    }
+    /**
+     * GET /admin/shaare/private/{hash} - Attach a private key to given bookmark, then redirect to the sharing URL.
+     */
+    public function sharePrivate(Request $request, Response $response, array $args): Response
+    {
+        $this->checkToken($request);
+        $hash = $args['hash'] ?? '';
+        $bookmark = $this->container->bookmarkService->findByHash($hash);
+        if ($bookmark->isPrivate() !== true) {
+            return $this->redirect($response, '/shaare/' . $hash);
+        }
+        if (empty($bookmark->getAdditionalContentEntry('private_key'))) {
+            $privateKey = bin2hex(random_bytes(16));
+            $bookmark->addAdditionalContentEntry('private_key', $privateKey);
+            $this->container->bookmarkService->set($bookmark);
+        }
+        return $this->redirect(
+            $response,
+            '/shaare/' . $hash . '?key=' . $bookmark->getAdditionalContentEntry('private_key')
+        );
+    }
+}
diff --git a/application/front/controller/admin/ShaarePublishController.php b/application/front/controller/admin/ShaarePublishController.php
new file mode 100644
index 00000000..fb9cacc2
--- /dev/null
+++ b/application/front/controller/admin/ShaarePublishController.php
@@ -0,0 +1,274 @@
+<?php
+declare(strict_types=1);
+namespace Shaarli\Front\Controller\Admin;
+use Shaarli\Bookmark\Bookmark;
+use Shaarli\Bookmark\Exception\BookmarkNotFoundException;
+use Shaarli\Formatter\BookmarkFormatter;
+use Shaarli\Formatter\BookmarkMarkdownFormatter;
+use Shaarli\Render\TemplatePage;
+use Shaarli\Thumbnailer;
+use Slim\Http\Request;
+use Slim\Http\Response;
+class ShaarePublishController extends ShaarliAdminController
+{
+    /**
+     * @var BookmarkFormatter[] Statically cached instances of formatters
+     */
+    protected $formatters = [];
+    /**
+     * @var array Statically cached bookmark's tags counts
+     */
+    protected $tags;
+    /**
+     * GET /admin/shaare - Displays the bookmark form for creation.
+     *                     Note that if the URL is found in existing bookmarks, then it will be in edit mode.
+     */
+    public function displayCreateForm(Request $request, Response $response): Response
+    {
+        $url = cleanup_url($request->getParam('post'));
+        $link = $this->buildLinkDataFromUrl($request, $url);
+        return $this->displayForm($link, $link['linkIsNew'], $request, $response);
+    }
+    /**
+     * POST /admin/shaare-batch - Displays multiple creation/edit forms from bulk add in add-link page.
+     */
+    public function displayCreateBatchForms(Request $request, Response $response): Response
+    {
+        $urls = array_map('cleanup_url', explode(PHP_EOL, $request->getParam('urls')));
+        $links = [];
+        foreach ($urls as $url) {
+            if (empty($url)) {
+                continue;
+            }
+            $link = $this->buildLinkDataFromUrl($request, $url);
+            $data = $this->buildFormData($link, $link['linkIsNew'], $request);
+            $data['token'] = $this->container->sessionManager->generateToken();
+            $data['source'] = 'batch';
+            $this->executePageHooks('render_editlink', $data, TemplatePage::EDIT_LINK);
+            $links[] = $data;
+        }
+        $this->assignView('links', $links);
+        $this->assignView('batch_mode', true);
+        $this->assignView('async_metadata', $this->container->conf->get('general.enable_async_metadata', true));
+        return $response->write($this->render(TemplatePage::EDIT_LINK_BATCH));
+    }
+    /**
+     * GET /admin/shaare/{id} - Displays the bookmark form in edition mode.
+     */
+    public function displayEditForm(Request $request, Response $response, array $args): Response
+    {
+        $id = $args['id'] ?? '';
+        try {
+            if (false === ctype_digit($id)) {
+                throw new BookmarkNotFoundException();
+            }
+            $bookmark = $this->container->bookmarkService->get((int) $id);  // Read database
+        } catch (BookmarkNotFoundException $e) {
+            $this->saveErrorMessage(sprintf(
+                t('Bookmark with identifier %s could not be found.'),
+                $id
+            ));
+            return $this->redirect($response, '/');
+        }
+        $formatter = $this->getFormatter('raw');
+        $link = $formatter->format($bookmark);
+        return $this->displayForm($link, false, $request, $response);
+    }
+    /**
+     * POST /admin/shaare
+     */
+    public function save(Request $request, Response $response): Response
+    {
+        $this->checkToken($request);
+        // lf_id should only be present if the link exists.
+        $id = $request->getParam('lf_id') !== null ? intval(escape($request->getParam('lf_id'))) : null;
+        if (null !== $id && true === $this->container->bookmarkService->exists($id)) {
+            // Edit
+            $bookmark = $this->container->bookmarkService->get($id);
+        } else {
+            // New link
+            $bookmark = new Bookmark();
+        }
+        $bookmark->setTitle($request->getParam('lf_title'));
+        $bookmark->setDescription($request->getParam('lf_description'));
+        $bookmark->setUrl($request->getParam('lf_url'), $this->container->conf->get('security.allowed_protocols', []));
+        $bookmark->setPrivate(filter_var($request->getParam('lf_private'), FILTER_VALIDATE_BOOLEAN));
+        $bookmark->setTagsString(
+            $request->getParam('lf_tags'),
+            $this->container->conf->get('general.tags_separator', ' ')
+        );
+        if (
+            $this->container->conf->get('thumbnails.mode', Thumbnailer::MODE_NONE) !== Thumbnailer::MODE_NONE
+            && true !== $this->container->conf->get('general.enable_async_metadata', true)
+            && $bookmark->shouldUpdateThumbnail()
+        ) {
+            $bookmark->setThumbnail($this->container->thumbnailer->get($bookmark->getUrl()));
+        }
+        $this->container->bookmarkService->addOrSet($bookmark, false);
+        // To preserve backward compatibility with 3rd parties, plugins still use arrays
+        $formatter = $this->getFormatter('raw');
+        $data = $formatter->format($bookmark);
+        $this->executePageHooks('save_link', $data);
+        $bookmark->fromArray($data, $this->container->conf->get('general.tags_separator', ' '));
+        $this->container->bookmarkService->set($bookmark);
+        // If we are called from the bookmarklet, we must close the popup:
+        if ($request->getParam('source') === 'bookmarklet') {
+            return $response->write('<script>self.close();</script>');
+        } elseif ($request->getParam('source') === 'batch') {
+            return $response;
+        }
+        if (!empty($request->getParam('returnurl'))) {
+            $this->container->environment['HTTP_REFERER'] = $request->getParam('returnurl');
+        }
+        return $this->redirectFromReferer(
+            $request,
+            $response,
+            ['/admin/add-shaare', '/admin/shaare'],
+            ['addlink', 'post', 'edit_link'],
+            $bookmark->getShortUrl()
+        );
+    }
+    /**
+     * Helper function used to display the shaare form whether it's a new or existing bookmark.
+     *
+     * @param array $link data used in template, either from parameters or from the data store
+     */
+    protected function displayForm(array $link, bool $isNew, Request $request, Response $response): Response
+    {
+        $data = $this->buildFormData($link, $isNew, $request);
+        $this->executePageHooks('render_editlink', $data, TemplatePage::EDIT_LINK);
+        foreach ($data as $key => $value) {
+            $this->assignView($key, $value);
+        }
+        $editLabel = false === $isNew ? t('Edit') . ' ' : '';
+        $this->assignView(
+            'pagetitle',
+            $editLabel . t('Shaare') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
+        );
+        return $response->write($this->render(TemplatePage::EDIT_LINK));
+    }
+    protected function buildLinkDataFromUrl(Request $request, string $url): array
+    {
+        // Check if URL is not already in database (in this case, we will edit the existing link)
+        $bookmark = $this->container->bookmarkService->findByUrl($url);
+        if (null === $bookmark) {
+            // Get shaare data if it was provided in URL (e.g.: by the bookmarklet).
+            $title = $request->getParam('title');
+            $description = $request->getParam('description');
+            $tags = $request->getParam('tags');
+            if ($request->getParam('private') !== null) {
+                $private = filter_var($request->getParam('private'), FILTER_VALIDATE_BOOLEAN);
+            } else {
+                $private = $this->container->conf->get('privacy.default_private_links', false);
+            }
+            // If this is an HTTP(S) link, we try go get the page to extract
+            // the title (otherwise we will to straight to the edit form.)
+            if (
+                true !== $this->container->conf->get('general.enable_async_metadata', true)
+                && empty($title)
+                && strpos(get_url_scheme($url) ?: '', 'http') !== false
+            ) {
+                $metadata = $this->container->metadataRetriever->retrieve($url);
+            }
+            if (empty($url)) {
+                $metadata['title'] = $this->container->conf->get('general.default_note_title', t('Note: '));
+            }
+            return [
+                'title' => $title ?? $metadata['title'] ?? '',
+                'url' => $url ?? '',
+                'description' => $description ?? $metadata['description'] ?? '',
+                'tags' => $tags ?? $metadata['tags'] ?? '',
+                'private' => $private,
+                'linkIsNew' => true,
+            ];
+        }
+        $formatter = $this->getFormatter('raw');
+        $link = $formatter->format($bookmark);
+        $link['linkIsNew'] = false;
+        return $link;
+    }
+    protected function buildFormData(array $link, bool $isNew, Request $request): array
+    {
+        $link['tags'] = $link['tags'] !== null && strlen($link['tags']) > 0
+            ? $link['tags'] . $this->container->conf->get('general.tags_separator', ' ')
+            : $link['tags']
+        ;
+        return escape([
+            'link' => $link,
+            'link_is_new' => $isNew,
+            'http_referer' => $this->container->environment['HTTP_REFERER'] ?? '',
+            'source' => $request->getParam('source') ?? '',
+            'tags' => $this->getTags(),
+            'default_private_links' => $this->container->conf->get('privacy.default_private_links', false),
+            'async_metadata' => $this->container->conf->get('general.enable_async_metadata', true),
+            'retrieve_description' => $this->container->conf->get('general.retrieve_description', false),
+        ]);
+    }
+    /**
+     * Memoize formatterFactory->getFormatter() calls.
+     */
+    protected function getFormatter(string $type): BookmarkFormatter
+    {
+        if (!array_key_exists($type, $this->formatters) || $this->formatters[$type] === null) {
+            $this->formatters[$type] = $this->container->formatterFactory->getFormatter($type);
+        }
+        return $this->formatters[$type];
+    }
+    /**
+     * Memoize bookmarkService->bookmarksCountPerTag() calls.
+     */
+    protected function getTags(): array
+    {
+        if ($this->tags === null) {
+            $this->tags = $this->container->bookmarkService->bookmarksCountPerTag();
+            if ($this->container->conf->get('formatter') === 'markdown') {
+                $this->tags[BookmarkMarkdownFormatter::NO_MD_TAG] = 1;
+            }
+        }
+        return $this->tags;
+    }
+}
diff --git a/application/front/controller/admin/ThumbnailsController.php b/application/front/controller/admin/ThumbnailsController.php
index 4dc09d38..94d97d4b 100644
--- a/application/front/controller/admin/ThumbnailsController.php
+++ b/application/front/controller/admin/ThumbnailsController.php
@@ -34,7 +34,7 @@ class ThumbnailsController extends ShaarliAdminController
        $this->assignView('ids', $ids);
        $this->assignView(
            'pagetitle',
-            t('Thumbnails update') .' - '. $this->container->conf->get('general.title', 'Shaarli')
+            t('Thumbnails update') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
        );
        return $response->write($this->render(TemplatePage::THUMBNAILS));
diff --git a/application/front/controller/admin/ToolsController.php b/application/front/controller/admin/ToolsController.php
index a87f20d2..560e5e3e 100644
--- a/application/front/controller/admin/ToolsController.php
+++ b/application/front/controller/admin/ToolsController.php
@@ -28,7 +28,7 @@ class ToolsController extends ShaarliAdminController
            $this->assignView($key, $value);
        }
-        $this->assignView('pagetitle', t('Tools') .' - '. $this->container->conf->get('general.title', 'Shaarli'));
+        $this->assignView('pagetitle', t('Tools') . ' - ' . $this->container->conf->get('general.title', 'Shaarli'));
        return $response->write($this->render(TemplatePage::TOOLS));
    }
diff --git a/application/front/controller/visitor/BookmarkListController.php b/application/front/controller/visitor/BookmarkListController.php
index 18368751..fe8231be 100644
--- a/application/front/controller/visitor/BookmarkListController.php
+++ b/application/front/controller/visitor/BookmarkListController.php
@@ -35,7 +35,8 @@ class BookmarkListController extends ShaarliVisitorController
        $formatter->addContextData('base_path', $this->container->basePath);
        $searchTags = normalize_spaces($request->getParam('searchtags') ?? '');
-        $searchTerm = escape(normalize_spaces($request->getParam('searchterm') ?? ''));;
+        $searchTerm = escape(normalize_spaces($request->getParam('searchterm') ?? ''));
+        ;
        // Filter bookmarks according search parameters.
        $visibility = $this->container->sessionManager->getSessionParameter('visibility');
@@ -95,6 +96,10 @@ class BookmarkListController extends ShaarliVisitorController
            $next_page_url = '?page=' . ($page - 1) . $searchtermUrl . $searchtagsUrl;
        }
+        $tagsSeparator = $this->container->conf->get('general.tags_separator', ' ');
+        $searchTagsUrlEncoded = array_map('urlencode', tags_str2array($searchTags, $tagsSeparator));
+        $searchTags = !empty($searchTags) ? trim($searchTags, $tagsSeparator) . $tagsSeparator : '';
        // Fill all template fields.
        $data = array_merge(
            $this->initializeTemplateVars(),
@@ -106,7 +111,7 @@ class BookmarkListController extends ShaarliVisitorController
                'result_count' => count($linksToDisplay),
                'search_term' => escape($searchTerm),
                'search_tags' => escape($searchTags),
-                'search_tags_url' => array_map('urlencode', explode(' ', $searchTags)),
+                'search_tags_url' => $searchTagsUrlEncoded,
                'visibility' => $visibility,
                'links' => $linkDisp,
            ]
@@ -119,8 +124,9 @@ class BookmarkListController extends ShaarliVisitorController
                return '[' . $tag . ']';
            };
            $data['pagetitle'] .= ! empty($searchTags)
-                ? implode(' ', array_map($bracketWrap, preg_split('/\s+/', $searchTags))) . ' '
+                ? implode(' ', array_map($bracketWrap, tags_str2array($searchTags, $tagsSeparator))) . ' '
-                : '';
+                : ''
+            ;
            $data['pagetitle'] .= '- ';
        }
@@ -137,8 +143,10 @@ class BookmarkListController extends ShaarliVisitorController
     */
    public function permalink(Request $request, Response $response, array $args): Response
    {
+        $privateKey = $request->getParam('key');
        try {
-            $bookmark = $this->container->bookmarkService->findByHash($args['hash']);
+            $bookmark = $this->container->bookmarkService->findByHash($args['hash'], $privateKey);
        } catch (BookmarkNotFoundException $e) {
            $this->assignView('error_message', $e->getMessage());
@@ -153,7 +161,7 @@ class BookmarkListController extends ShaarliVisitorController
        $data = array_merge(
            $this->initializeTemplateVars(),
            [
-                'pagetitle' => $bookmark->getTitle() .' - '. $this->container->conf->get('general.title', 'Shaarli'),
+                'pagetitle' => $bookmark->getTitle() . ' - ' . $this->container->conf->get('general.title', 'Shaarli'),
                'links' => [$formatter->format($bookmark)],
            ]
        );
@@ -169,19 +177,25 @@ class BookmarkListController extends ShaarliVisitorController
     */
    protected function updateThumbnail(Bookmark $bookmark, bool $writeDatastore = true): bool
    {
-        // Logged in, thumbnails enabled, not a note, is HTTP
+        if (false === $this->container->loginManager->isLoggedIn()) {
-        // and (never retrieved yet or no valid cache file)
+            return false;
-        if ($this->container->loginManager->isLoggedIn()
+        }
-            && $this->container->conf->get('thumbnails.mode', Thumbnailer::MODE_NONE) !== Thumbnailer::MODE_NONE
-            && false !== $bookmark->getThumbnail()
+        // If thumbnail should be updated, we reset it to null
-            && !$bookmark->isNote()
+        if ($bookmark->shouldUpdateThumbnail()) {
-            && (null === $bookmark->getThumbnail() || !is_file($bookmark->getThumbnail()))
+            $bookmark->setThumbnail(null);
-            && startsWith(strtolower($bookmark->getUrl()), 'http')
-        ) {
+            // Requires an update, not async retrieval, thumbnails enabled
-            $bookmark->setThumbnail($this->container->thumbnailer->get($bookmark->getUrl()));
+            if (
-            $this->container->bookmarkService->set($bookmark, $writeDatastore);
+                $bookmark->shouldUpdateThumbnail()
+                && true !== $this->container->conf->get('general.enable_async_metadata', true)
-            return true;
+                && $this->container->conf->get('thumbnails.mode', Thumbnailer::MODE_NONE) !== Thumbnailer::MODE_NONE
+            ) {
+                $bookmark->setThumbnail($this->container->thumbnailer->get($bookmark->getUrl()));
+                $this->container->bookmarkService->set($bookmark, $writeDatastore);
+                return true;
+            }
        }
        return false;
@@ -198,6 +212,7 @@ class BookmarkListController extends ShaarliVisitorController
            'page_max' => '',
            'search_tags' => '',
            'result_count' => '',
+            'async_metadata' => $this->container->conf->get('general.enable_async_metadata', true)
        ];
    }
diff --git a/application/front/controller/visitor/DailyController.php b/application/front/controller/visitor/DailyController.php
index 07617cf1..29492a5f 100644
--- a/application/front/controller/visitor/DailyController.php
+++ b/application/front/controller/visitor/DailyController.php
@@ -5,8 +5,8 @@ declare(strict_types=1);
 namespace Shaarli\Front\Controller\Visitor;
 use DateTime;
-use DateTimeImmutable;
 use Shaarli\Bookmark\Bookmark;
+use Shaarli\Helper\DailyPageHelper;
 use Shaarli\Render\TemplatePage;
 use Slim\Http\Request;
 use Slim\Http\Response;
@@ -26,32 +26,20 @@ class DailyController extends ShaarliVisitorController
     */
    public function index(Request $request, Response $response): Response
    {
-        $day = $request->getQueryParam('day') ?? date('Ymd');
+        $type = DailyPageHelper::extractRequestedType($request);
+        $format = DailyPageHelper::getFormatByType($type);
-        $availableDates = $this->container->bookmarkService->days();
+        $latestBookmark = $this->container->bookmarkService->getLatest();
-        $nbAvailableDates = count($availableDates);
+        $dateTime = DailyPageHelper::extractRequestedDateTime($type, $request->getQueryParam($type), $latestBookmark);
-        $index = array_search($day, $availableDates);
+        $start = DailyPageHelper::getStartDateTimeByType($type, $dateTime);
+        $end = DailyPageHelper::getEndDateTimeByType($type, $dateTime);
-        if ($index === false) {
+        $dailyDesc = DailyPageHelper::getDescriptionByType($type, $dateTime);
-            // no bookmarks for day, but at least one day with bookmarks
-            $day = $availableDates[$nbAvailableDates - 1] ?? $day;
+        $linksToDisplay = $this->container->bookmarkService->findByDate(
-            $previousDay = $availableDates[$nbAvailableDates - 2] ?? '';
+            $start,
-        } else {
+            $end,
-            $previousDay = $availableDates[$index - 1] ?? '';
+            $previousDay,
-            $nextDay = $availableDates[$index + 1] ?? '';
+            $nextDay
-        }
+        );
-        if ($day === date('Ymd')) {
-            $this->assignView('dayDesc', t('Today'));
-        } elseif ($day === date('Ymd', strtotime('-1 days'))) {
-            $this->assignView('dayDesc', t('Yesterday'));
-        }
-        try {
-            $linksToDisplay = $this->container->bookmarkService->filterDay($day);
-        } catch (\Exception $exc) {
-            $linksToDisplay = [];
-        }
        $formatter = $this->container->formatterFactory->getFormatter();
        $formatter->addContextData('base_path', $this->container->basePath);
@@ -63,13 +51,15 @@ class DailyController extends ShaarliVisitorController
            $linksToDisplay[$key]['description'] = $bookmark->getDescription();
        }
-        $dayDate = DateTime::createFromFormat(Bookmark::LINK_DATE_FORMAT, $day.'_000000');
        $data = [
            'linksToDisplay' => $linksToDisplay,
-            'day' => $dayDate->getTimestamp(),
+            'dayDate' => $start,
-            'dayDate' => $dayDate,
+            'day' => $start->getTimestamp(),
-            'previousday' => $previousDay ?? '',
+            'previousday' => $previousDay ? $previousDay->format($format) : '',
-            'nextday' => $nextDay ?? '',
+            'nextday' => $nextDay ? $nextDay->format($format) : '',
+            'dayDesc' => $dailyDesc,
+            'type' => $type,
+            'localizedType' => $this->translateType($type),
        ];
        // Hooks are called before column construction so that plugins don't have to deal with columns.
@@ -82,7 +72,7 @@ class DailyController extends ShaarliVisitorController
        $mainTitle = $this->container->conf->get('general.title', 'Shaarli');
        $this->assignView(
            'pagetitle',
-            t('Daily') .' - '. format_date($dayDate, false) . ' - ' . $mainTitle
+            $data['localizedType'] . ' - ' . $data['dayDesc'] . ' - ' . $mainTitle
        );
        return $response->write($this->render(TemplatePage::DAILY));
@@ -96,9 +86,11 @@ class DailyController extends ShaarliVisitorController
    public function rss(Request $request, Response $response): Response
    {
        $response = $response->withHeader('Content-Type', 'application/rss+xml; charset=utf-8');
+        $type = DailyPageHelper::extractRequestedType($request);
+        $cacheDuration = DailyPageHelper::getCacheDatePeriodByType($type);
        $pageUrl = page_url($this->container->environment);
-        $cache = $this->container->pageCacheManager->getCachePage($pageUrl);
+        $cache = $this->container->pageCacheManager->getCachePage($pageUrl, $cacheDuration);
        $cached = $cache->cachedVersion();
        if (!empty($cached)) {
@@ -106,11 +98,13 @@ class DailyController extends ShaarliVisitorController
        }
        $days = [];
+        $format = DailyPageHelper::getFormatByType($type);
+        $length = DailyPageHelper::getRssLengthByType($type);
        foreach ($this->container->bookmarkService->search() as $bookmark) {
-            $day = $bookmark->getCreated()->format('Ymd');
+            $day = $bookmark->getCreated()->format($format);
            // Stop iterating after DAILY_RSS_NB_DAYS entries
-            if (count($days) === static::$DAILY_RSS_NB_DAYS && !isset($days[$day])) {
+            if (count($days) === $length && !isset($days[$day])) {
                break;
            }
@@ -127,12 +121,19 @@ class DailyController extends ShaarliVisitorController
        /** @var Bookmark[] $bookmarks */
        foreach ($days as $day => $bookmarks) {
-            $dayDatetime = DateTimeImmutable::createFromFormat(Bookmark::LINK_DATE_FORMAT, $day.'_000000');
+            $dayDateTime = DailyPageHelper::extractRequestedDateTime($type, (string) $day);
+            $endDateTime = DailyPageHelper::getEndDateTimeByType($type, $dayDateTime);
+            // We only want the RSS entry to be published when the period is over.
+            if (new DateTime() < $endDateTime) {
+                continue;
+            }
            $dataPerDay[$day] = [
-                'date' => $dayDatetime,
+                'date' => $endDateTime,
-                'date_rss' => $dayDatetime->format(DateTime::RSS),
+                'date_rss' => $endDateTime->format(DateTime::RSS),
-                'date_human' => format_date($dayDatetime, false, true),
+                'date_human' => DailyPageHelper::getDescriptionByType($type, $dayDateTime, false),
-                'absolute_url' => $indexUrl . 'daily?day=' . $day,
+                'absolute_url' => $indexUrl . 'daily?' . $type . '=' . $day,
                'links' => [],
            ];
@@ -141,16 +142,20 @@ class DailyController extends ShaarliVisitorController
                // Make permalink URL absolute
                if ($bookmark->isNote()) {
-                    $dataPerDay[$day]['links'][$key]['url'] = $indexUrl . $bookmark->getUrl();
+                    $dataPerDay[$day]['links'][$key]['url'] = rtrim($indexUrl, '/') . $bookmark->getUrl();
                }
            }
        }
-        $this->assignView('title', $this->container->conf->get('general.title', 'Shaarli'));
+        $this->assignAllView([
-        $this->assignView('index_url', $indexUrl);
+            'title' => $this->container->conf->get('general.title', 'Shaarli'),
-        $this->assignView('page_url', $pageUrl);
+            'index_url' => $indexUrl,
-        $this->assignView('hide_timestamps', $this->container->conf->get('privacy.hide_timestamps', false));
+            'page_url' => $pageUrl,
-        $this->assignView('days', $dataPerDay);
+            'hide_timestamps' => $this->container->conf->get('privacy.hide_timestamps', false),
+            'days' => $dataPerDay,
+            'type' => $type,
+            'localizedType' => $this->translateType($type),
+        ]);
        $rssContent = $this->render(TemplatePage::DAILY_RSS);
@@ -189,4 +194,13 @@ class DailyController extends ShaarliVisitorController
        return $columns;
    }
+    protected function translateType($type): string
+    {
+        return [
+            t('day') => t('Daily'),
+            t('week') => t('Weekly'),
+            t('month') => t('Monthly'),
+        ][t($type)] ?? t('Daily');
+    }
 }
diff --git a/application/front/controller/visitor/ErrorController.php b/application/front/controller/visitor/ErrorController.php
index 10aa84c8..428e8254 100644
--- a/application/front/controller/visitor/ErrorController.php
+++ b/application/front/controller/visitor/ErrorController.php
@@ -26,12 +26,15 @@ class ErrorController extends ShaarliVisitorController
            $response = $response->withStatus($throwable->getCode());
        } else {
            // Internal error (any other Throwable)
-            if ($this->container->conf->get('dev.debug', false)) {
+            if ($this->container->conf->get('dev.debug', false) || $this->container->loginManager->isLoggedIn()) {
-                $this->assignView('message', $throwable->getMessage());
+                $this->assignView('message', t('Error: ') . $throwable->getMessage());
                $this->assignView(
-                    'stacktrace',
+                    'text',
-                    nl2br(get_class($throwable) .': '. PHP_EOL . $throwable->getTraceAsString())
+                    '<a href="https://github.com/shaarli/Shaarli/issues/new">'
+                    . t('Please report it on Github.')
+                    . '</a>'
                );
+                $this->assignView('stacktrace', exception2text($throwable));
            } else {
                $this->assignView('message', t('An unexpected error occurred.'));
            }
@@ -39,7 +42,6 @@ class ErrorController extends ShaarliVisitorController
            $response = $response->withStatus(500);
        }
        return $response->write($this->render('error'));
    }
 }
diff --git a/application/front/controller/visitor/FeedController.php b/application/front/controller/visitor/FeedController.php
index 8d8b546a..edc7ef43 100644
--- a/application/front/controller/visitor/FeedController.php
+++ b/application/front/controller/visitor/FeedController.php
@@ -27,7 +27,7 @@ class FeedController extends ShaarliVisitorController
    protected function processRequest(string $feedType, Request $request, Response $response): Response
    {
-        $response = $response->withHeader('Content-Type', 'application/'. $feedType .'+xml; charset=utf-8');
+        $response = $response->withHeader('Content-Type', 'application/' . $feedType . '+xml; charset=utf-8');
        $pageUrl = page_url($this->container->environment);
        $cache = $this->container->pageCacheManager->getCachePage($pageUrl);
diff --git a/application/front/controller/visitor/InstallController.php b/application/front/controller/visitor/InstallController.php
index 7cb32777..418d4a49 100644
--- a/application/front/controller/visitor/InstallController.php
+++ b/application/front/controller/visitor/InstallController.php
@@ -4,10 +4,10 @@ declare(strict_types=1);
 namespace Shaarli\Front\Controller\Visitor;
-use Shaarli\ApplicationUtils;
 use Shaarli\Container\ShaarliContainer;
 use Shaarli\Front\Exception\AlreadyInstalledException;
 use Shaarli\Front\Exception\ResourcePermissionException;
+use Shaarli\Helper\ApplicationUtils;
 use Shaarli\Languages;
 use Shaarli\Security\SessionManager;
 use Slim\Http\Request;
@@ -39,7 +39,8 @@ class InstallController extends ShaarliVisitorController
        // Before installation, we'll make sure that permissions are set properly, and sessions are working.
        $this->checkPermissions();
-        if (static::SESSION_TEST_VALUE
+        if (
+            static::SESSION_TEST_VALUE
            !== $this->container->sessionManager->getSessionParameter(static::SESSION_TEST_KEY)
        ) {
            $this->container->sessionManager->setSessionParameter(static::SESSION_TEST_KEY, static::SESSION_TEST_VALUE);
@@ -53,6 +54,21 @@ class InstallController extends ShaarliVisitorController
        $this->assignView('cities', $cities);
        $this->assignView('languages', Languages::getAvailableLanguages());
+        $phpEol = new \DateTimeImmutable(ApplicationUtils::getPhpEol(PHP_VERSION));
+        $permissions = array_merge(
+            ApplicationUtils::checkResourcePermissions($this->container->conf),
+            ApplicationUtils::checkDatastoreMutex()
+        );
+        $this->assignView('php_version', PHP_VERSION);
+        $this->assignView('php_eol', format_date($phpEol, false));
+        $this->assignView('php_has_reached_eol', $phpEol < new \DateTimeImmutable());
+        $this->assignView('php_extensions', ApplicationUtils::getPhpExtensionsRequirement());
+        $this->assignView('permissions', $permissions);
+        $this->assignView('pagetitle', t('Install Shaarli'));
        return $response->write($this->render('install'));
    }
@@ -65,17 +81,18 @@ class InstallController extends ShaarliVisitorController
        // This part makes sure sessions works correctly.
        // (Because on some hosts, session.save_path may not be set correctly,
        // or we may not have write access to it.)
-        if (static::SESSION_TEST_VALUE
+        if (
+            static::SESSION_TEST_VALUE
            !== $this->container->sessionManager->getSessionParameter(static::SESSION_TEST_KEY)
        ) {
            // Step 2: Check if data in session is correct.
            $msg = t(
-                '<pre>Sessions do not seem to work correctly on your server.<br>'.
+                '<pre>Sessions do not seem to work correctly on your server.<br>' .
-                'Make sure the variable "session.save_path" is set correctly in your PHP config, '.
+                'Make sure the variable "session.save_path" is set correctly in your PHP config, ' .
-                'and that you have write access to it.<br>'.
+                'and that you have write access to it.<br>' .
-                'It currently points to %s.<br>'.
+                'It currently points to %s.<br>' .
-                'On some browsers, accessing your server via a hostname like \'localhost\' '.
+                'On some browsers, accessing your server via a hostname like \'localhost\' ' .
-                'or any custom hostname without a dot causes cookie storage to fail. '.
+                'or any custom hostname without a dot causes cookie storage to fail. ' .
                'We recommend accessing your server via it\'s IP address or Fully Qualified Domain Name.<br>'
            );
            $msg = sprintf($msg, $this->container->sessionManager->getSavePath());
@@ -94,7 +111,8 @@ class InstallController extends ShaarliVisitorController
    public function save(Request $request, Response $response): Response
    {
        $timezone = 'UTC';
-        if (!empty($request->getParam('continent'))
+        if (
+            !empty($request->getParam('continent'))
            && !empty($request->getParam('city'))
            && isTimeZoneValid($request->getParam('continent'), $request->getParam('city'))
        ) {
@@ -104,7 +122,7 @@ class InstallController extends ShaarliVisitorController
        $login = $request->getParam('setlogin');
        $this->container->conf->set('credentials.login', $login);
-        $salt = sha1(uniqid('', true) .'_'. mt_rand());
+        $salt = sha1(uniqid('', true) . '_' . mt_rand());
        $this->container->conf->set('credentials.salt', $salt);
        $this->container->conf->set('credentials.hash', sha1($request->getParam('setpassword') . $login . $salt));
@@ -113,7 +131,7 @@ class InstallController extends ShaarliVisitorController
        } else {
            $this->container->conf->set(
                'general.title',
-                'Shared bookmarks on '.escape(index_url($this->container->environment))
+                'Shared bookmarks on ' . escape(index_url($this->container->environment))
            );
        }
@@ -150,7 +168,7 @@ class InstallController extends ShaarliVisitorController
    protected function checkPermissions(): bool
    {
        // Ensure Shaarli has proper access to its resources
-        $errors = ApplicationUtils::checkResourcePermissions($this->container->conf);
+        $errors = ApplicationUtils::checkResourcePermissions($this->container->conf, true);
        if (empty($errors)) {
            return true;
        }
diff --git a/application/front/controller/visitor/LoginController.php b/application/front/controller/visitor/LoginController.php
index 121ba40b..4b881535 100644
--- a/application/front/controller/visitor/LoginController.php
+++ b/application/front/controller/visitor/LoginController.php
@@ -43,7 +43,7 @@ class LoginController extends ShaarliVisitorController
        $this
            ->assignView('returnurl', escape($returnUrl))
            ->assignView('remember_user_default', $this->container->conf->get('privacy.remember_user_default', true))
-            ->assignView('pagetitle', t('Login') .' - '. $this->container->conf->get('general.title', 'Shaarli'))
+            ->assignView('pagetitle', t('Login') . ' - ' . $this->container->conf->get('general.title', 'Shaarli'))
        ;
        return $response->write($this->render(TemplatePage::LOGIN));
@@ -64,8 +64,8 @@ class LoginController extends ShaarliVisitorController
            return $this->redirect($response, '/');
        }
-        if (!$this->container->loginManager->checkCredentials(
+        if (
-                $this->container->environment['REMOTE_ADDR'],
+            !$this->container->loginManager->checkCredentials(
                client_ip_id($this->container->environment),
                $request->getParam('login'),
                $request->getParam('password')
@@ -102,7 +102,8 @@ class LoginController extends ShaarliVisitorController
     */
    protected function checkLoginState(): bool
    {
-        if ($this->container->loginManager->isLoggedIn()
+        if (
+            $this->container->loginManager->isLoggedIn()
            || $this->container->conf->get('security.open_shaarli', false)
        ) {
            throw new CantLoginException();
diff --git a/application/front/controller/visitor/PictureWallController.php b/application/front/controller/visitor/PictureWallController.php
index 3c57f8dd..23553ee6 100644
--- a/application/front/controller/visitor/PictureWallController.php
+++ b/application/front/controller/visitor/PictureWallController.php
@@ -26,7 +26,7 @@ class PictureWallController extends ShaarliVisitorController
        $this->assignView(
            'pagetitle',
-            t('Picture wall') .' - '. $this->container->conf->get('general.title', 'Shaarli')
+            t('Picture wall') . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
        );
        // Optionally filter the results:
diff --git a/application/front/controller/visitor/ShaarliVisitorController.php b/application/front/controller/visitor/ShaarliVisitorController.php
index 54f9fe03..ae946c59 100644
--- a/application/front/controller/visitor/ShaarliVisitorController.php
+++ b/application/front/controller/visitor/ShaarliVisitorController.php
@@ -144,7 +144,8 @@ abstract class ShaarliVisitorController
        if (null !== $referer) {
            $currentUrl = parse_url($referer);
            // If the referer is not related to Shaarli instance, redirect to default
-            if (isset($currentUrl['host'])
+            if (
+                isset($currentUrl['host'])
                && strpos(index_url($this->container->environment), $currentUrl['host']) === false
            ) {
                return $response->withRedirect($defaultPath);
@@ -173,7 +174,7 @@ abstract class ShaarliVisitorController
            }
        }
-        $queryString = count($params) > 0 ? '?'. http_build_query($params) : '';
+        $queryString = count($params) > 0 ? '?' . http_build_query($params) : '';
        $anchor = $anchor ? '#' . $anchor : '';
        return $response->withRedirect($path . $queryString . $anchor);
diff --git a/application/front/controller/visitor/TagCloudController.php b/application/front/controller/visitor/TagCloudController.php
index 76ed7690..46d62779 100644
--- a/application/front/controller/visitor/TagCloudController.php
+++ b/application/front/controller/visitor/TagCloudController.php
@@ -47,13 +47,14 @@ class TagCloudController extends ShaarliVisitorController
     */
    protected function processRequest(string $type, Request $request, Response $response): Response
    {
+        $tagsSeparator = $this->container->conf->get('general.tags_separator', ' ');
        if ($this->container->loginManager->isLoggedIn() === true) {
            $visibility = $this->container->sessionManager->getSessionParameter('visibility');
        }
        $sort = $request->getQueryParam('sort');
        $searchTags = $request->getQueryParam('searchtags');
-        $filteringTags = $searchTags !== null ? explode(' ', $searchTags) : [];
+        $filteringTags = $searchTags !== null ? explode($tagsSeparator, $searchTags) : [];
        $tags = $this->container->bookmarkService->bookmarksCountPerTag($filteringTags, $visibility ?? null);
@@ -71,8 +72,9 @@ class TagCloudController extends ShaarliVisitorController
            $tagsUrl[escape($tag)] = urlencode((string) $tag);
        }
-        $searchTags = implode(' ', escape($filteringTags));
+        $searchTags = tags_array2str($filteringTags, $tagsSeparator);
-        $searchTagsUrl = urlencode(implode(' ', $filteringTags));
+        $searchTags = !empty($searchTags) ? trim($searchTags, $tagsSeparator) . $tagsSeparator : '';
+        $searchTagsUrl = urlencode($searchTags);
        $data = [
            'search_tags' => escape($searchTags),
            'search_tags_url' => $searchTagsUrl,
@@ -82,10 +84,10 @@ class TagCloudController extends ShaarliVisitorController
        $this->executePageHooks('render_tag' . $type, $data, 'tag.' . $type);
        $this->assignAllView($data);
-        $searchTags = !empty($searchTags) ? $searchTags .' - ' : '';
+        $searchTags = !empty($searchTags) ? trim(str_replace($tagsSeparator, ' ', $searchTags)) . ' - ' : '';
        $this->assignView(
            'pagetitle',
-            $searchTags . t('Tag '. $type) .' - '. $this->container->conf->get('general.title', 'Shaarli')
+            $searchTags . t('Tag ' . $type) . ' - ' . $this->container->conf->get('general.title', 'Shaarli')
        );
        return $response->write($this->render('tag.' . $type));
diff --git a/application/front/controller/visitor/TagController.php b/application/front/controller/visitor/TagController.php
index de4e7ea2..3aa58542 100644
--- a/application/front/controller/visitor/TagController.php
+++ b/application/front/controller/visitor/TagController.php
@@ -27,7 +27,7 @@ class TagController extends ShaarliVisitorController
        // In case browser does not send HTTP_REFERER, we search a single tag
        if (null === $referer) {
            if (null !== $newTag) {
-                return $this->redirect($response, '/?searchtags='. urlencode($newTag));
+                return $this->redirect($response, '/?searchtags=' . urlencode($newTag));
            }
            return $this->redirect($response, '/');
@@ -37,7 +37,7 @@ class TagController extends ShaarliVisitorController
        parse_str($currentUrl['query'] ?? '', $params);
        if (null === $newTag) {
-            return $response->withRedirect(($currentUrl['path'] ?? './') .'?'. http_build_query($params));
+            return $response->withRedirect(($currentUrl['path'] ?? './') . '?' . http_build_query($params));
        }
        // Prevent redirection loop
@@ -45,9 +45,10 @@ class TagController extends ShaarliVisitorController
            unset($params['addtag']);
        }
+        $tagsSeparator = $this->container->conf->get('general.tags_separator', ' ');
        // Check if this tag is already in the search query and ignore it if it is.
        // Each tag is always separated by a space
-        $currentTags = isset($params['searchtags']) ? explode(' ', $params['searchtags']) : [];
+        $currentTags = tags_str2array($params['searchtags'] ?? '', $tagsSeparator);
        $addtag = true;
        foreach ($currentTags as $value) {
@@ -62,12 +63,12 @@ class TagController extends ShaarliVisitorController
            $currentTags[] = trim($newTag);
        }
-        $params['searchtags'] = trim(implode(' ', $currentTags));
+        $params['searchtags'] = tags_array2str($currentTags, $tagsSeparator);
        // We also remove page (keeping the same page has no sense, since the results are different)
        unset($params['page']);
-        return $response->withRedirect(($currentUrl['path'] ?? './') .'?'. http_build_query($params));
+        return $response->withRedirect(($currentUrl['path'] ?? './') . '?' . http_build_query($params));
    }
    /**
@@ -89,7 +90,7 @@ class TagController extends ShaarliVisitorController
        parse_str($currentUrl['query'] ?? '', $params);
        if (null === $tagToRemove) {
-            return $response->withRedirect(($currentUrl['path'] ?? './') .'?'. http_build_query($params));
+            return $response->withRedirect(($currentUrl['path'] ?? './') . '?' . http_build_query($params));
        }
        // Prevent redirection loop
@@ -98,10 +99,11 @@ class TagController extends ShaarliVisitorController
        }
        if (isset($params['searchtags'])) {
-            $tags = explode(' ', $params['searchtags']);
+            $tagsSeparator = $this->container->conf->get('general.tags_separator', ' ');
+            $tags = tags_str2array($params['searchtags'] ?? '', $tagsSeparator);
            // Remove value from array $tags.
            $tags = array_diff($tags, [$tagToRemove]);
-            $params['searchtags'] = implode(' ', $tags);
+            $params['searchtags'] = tags_array2str($tags, $tagsSeparator);
            if (empty($params['searchtags'])) {
                unset($params['searchtags']);
diff --git a/application/ApplicationUtils.php b/application/helper/ApplicationUtils.php
index 3aa21829..a6c03aae 100644
--- a/application/ApplicationUtils.php
+++ b/application/helper/ApplicationUtils.php
@@ -1,7 +1,10 @@
 <?php
-namespace Shaarli;
+namespace Shaarli\Helper;
 use Exception;
+use malkusch\lock\exception\LockAcquireException;
+use malkusch\lock\mutex\FlockMutex;
 use Shaarli\Config\ConfigManager;
 /**
@@ -14,8 +17,9 @@ class ApplicationUtils
     */
    public static $VERSION_FILE = 'shaarli_version.php';
-    private static $GIT_URL = 'https://raw.githubusercontent.com/shaarli/Shaarli';
+    public static $GITHUB_URL = 'https://github.com/shaarli/Shaarli';
-    private static $GIT_BRANCHES = array('latest', 'stable');
+    public static $GIT_RAW_URL = 'https://raw.githubusercontent.com/shaarli/Shaarli';
+    public static $GIT_BRANCHES = ['latest', 'stable'];
    private static $VERSION_START_TAG = '<?php /* ';
    private static $VERSION_END_TAG = ' */ ?>';
@@ -63,8 +67,8 @@ class ApplicationUtils
        }
        return str_replace(
-            array(self::$VERSION_START_TAG, self::$VERSION_END_TAG, PHP_EOL),
+            [self::$VERSION_START_TAG, self::$VERSION_END_TAG, PHP_EOL],
-            array('', '', ''),
+            ['', '', ''],
            $data
        );
    }
@@ -125,7 +129,7 @@ class ApplicationUtils
        // Late Static Binding allows overriding within tests
        // See http://php.net/manual/en/language.oop5.late-static-bindings.php
        $latestVersion = static::getVersion(
-            self::$GIT_URL . '/' . $branch . '/' . self::$VERSION_FILE
+            self::$GIT_RAW_URL . '/' . $branch . '/' . self::$VERSION_FILE
        );
        if (!$latestVersion) {
@@ -171,35 +175,47 @@ class ApplicationUtils
    /**
     * Checks Shaarli has the proper access permissions to its resources
     *
-     * @param ConfigManager $conf Configuration Manager instance.
+     * @param ConfigManager $conf        Configuration Manager instance.
+     * @param bool          $minimalMode In minimal mode we only check permissions to be able to display a template.
+     *                                   Currently we only need to be able to read the theme and write in raintpl cache.
     *
     * @return array A list of the detected configuration issues
     */
-    public static function checkResourcePermissions($conf)
+    public static function checkResourcePermissions(ConfigManager $conf, bool $minimalMode = false): array
    {
-        $errors = array();
+        $errors = [];
        $rainTplDir = rtrim($conf->get('resource.raintpl_tpl'), '/');
        // Check script and template directories are readable
-        foreach (array(
+        foreach (
-                     'application',
+            [
-                     'inc',
+            'application',
-                     'plugins',
+            'inc',
-                     $rainTplDir,
+            'plugins',
-                     $rainTplDir . '/' . $conf->get('resource.theme'),
+            $rainTplDir,
-                 ) as $path) {
+            $rainTplDir . '/' . $conf->get('resource.theme'),
+            ] as $path
+        ) {
            if (!is_readable(realpath($path))) {
                $errors[] = '"' . $path . '" ' . t('directory is not readable');
            }
        }
        // Check cache and data directories are readable and writable
-        foreach (array(
+        if ($minimalMode) {
-                     $conf->get('resource.thumbnails_cache'),
+            $folders = [
-                     $conf->get('resource.data_dir'),
+                $conf->get('resource.raintpl_tmp'),
-                     $conf->get('resource.page_cache'),
+            ];
-                     $conf->get('resource.raintpl_tmp'),
+        } else {
-                 ) as $path) {
+            $folders = [
+            $conf->get('resource.thumbnails_cache'),
+            $conf->get('resource.data_dir'),
+            $conf->get('resource.page_cache'),
+            $conf->get('resource.raintpl_tmp'),
+            ];
+        }
+        foreach ($folders as $path) {
            if (!is_readable(realpath($path))) {
                $errors[] = '"' . $path . '" ' . t('directory is not readable');
            }
@@ -208,14 +224,20 @@ class ApplicationUtils
            }
        }
+        if ($minimalMode) {
+            return $errors;
+        }
        // Check configuration files are readable and writable
-        foreach (array(
+        foreach (
-                     $conf->getConfigFileExt(),
+            [
-                     $conf->get('resource.datastore'),
+                 $conf->getConfigFileExt(),
-                     $conf->get('resource.ban_file'),
+                 $conf->get('resource.datastore'),
-                     $conf->get('resource.log'),
+                 $conf->get('resource.ban_file'),
-                     $conf->get('resource.update_check'),
+                 $conf->get('resource.log'),
-                 ) as $path) {
+                 $conf->get('resource.update_check'),
+             ] as $path
+        ) {
            if (!is_file(realpath($path))) {
                # the file may not exist yet
                continue;
@@ -232,6 +254,20 @@ class ApplicationUtils
        return $errors;
    }
+    public static function checkDatastoreMutex(): array
+    {
+        $mutex = new FlockMutex(fopen(SHAARLI_MUTEX_FILE, 'r'), 2);
+        try {
+            $mutex->synchronized(function () {
+                return true;
+            });
+        } catch (LockAcquireException $e) {
+            $errors[] = t('Lock can not be acquired on the datastore. You might encounter concurrent access issues.');
+        }
+        return $errors ?? [];
+    }
    /**
     * Returns a salted hash representing the current Shaarli version.
     *
@@ -246,4 +282,54 @@ class ApplicationUtils
    {
        return hash_hmac('sha256', $currentVersion, $salt);
    }
+    /**
+     * Get a list of PHP extensions used by Shaarli.
+     *
+     * @return array[] List of extension with following keys:
+     *                   - name: extension name
+     *                   - required: whether the extension is required to use Shaarli
+     *                   - desc: short description of extension usage in Shaarli
+     *                   - loaded: whether the extension is properly loaded or not
+     */
+    public static function getPhpExtensionsRequirement(): array
+    {
+        $extensions = [
+            ['name' => 'json', 'required' => true, 'desc' => t('Configuration parsing')],
+            ['name' => 'simplexml', 'required' => true, 'desc' => t('Slim Framework (routing, etc.)')],
+            ['name' => 'mbstring', 'required' => true, 'desc' => t('Multibyte (Unicode) string support')],
+            ['name' => 'gd', 'required' => false, 'desc' => t('Required to use thumbnails')],
+            ['name' => 'intl', 'required' => false, 'desc' => t('Localized text sorting (e.g. e->è->f)')],
+            ['name' => 'curl', 'required' => false, 'desc' => t('Better retrieval of bookmark metadata and thumbnail')],
+            ['name' => 'gettext', 'required' => false, 'desc' => t('Use the translation system in gettext mode')],
+            ['name' => 'ldap', 'required' => false, 'desc' => t('Login using LDAP server')],
+        ];
+        foreach ($extensions as &$extension) {
+            $extension['loaded'] = extension_loaded($extension['name']);
+        }
+        return $extensions;
+    }
+    /**
+     * Return the EOL date of given PHP version. If the version is unknown,
+     * we return today + 2 years.
+     *
+     * @param string $fullVersion PHP version, e.g. 7.4.7
+     *
+     * @return string Date format: YYYY-MM-DD
+     */
+    public static function getPhpEol(string $fullVersion): string
+    {
+        preg_match('/(\d+\.\d+)\.\d+/', $fullVersion, $matches);
+        return [
+            '7.1' => '2019-12-01',
+            '7.2' => '2020-11-30',
+            '7.3' => '2021-12-06',
+            '7.4' => '2022-11-28',
+            '8.0' => '2023-12-01',
+        ][$matches[1]] ?? (new \DateTime('+2 year'))->format('Y-m-d');
+    }
 }
diff --git a/application/helper/DailyPageHelper.php b/application/helper/DailyPageHelper.php
new file mode 100644
index 00000000..05f95812
--- /dev/null
+++ b/application/helper/DailyPageHelper.php
@@ -0,0 +1,236 @@
+<?php
+declare(strict_types=1);
+namespace Shaarli\Helper;
+use DatePeriod;
+use DateTimeImmutable;
+use Exception;
+use Shaarli\Bookmark\Bookmark;
+use Slim\Http\Request;
+class DailyPageHelper
+{
+    public const MONTH = 'month';
+    public const WEEK = 'week';
+    public const DAY = 'day';
+    /**
+     * Extracts the type of the daily to display from the HTTP request parameters
+     *
+     * @param Request $request HTTP request
+     *
+     * @return string month/week/day
+     */
+    public static function extractRequestedType(Request $request): string
+    {
+        if ($request->getQueryParam(static::MONTH) !== null) {
+            return static::MONTH;
+        } elseif ($request->getQueryParam(static::WEEK) !== null) {
+            return static::WEEK;
+        }
+        return static::DAY;
+    }
+    /**
+     * Extracts a DateTimeImmutable from provided HTTP request.
+     * If no parameter is provided, we rely on the creation date of the latest provided created bookmark.
+     * If the datastore is empty or no bookmark is provided, we use the current date.
+     *
+     * @param string        $type           month/week/day
+     * @param string|null   $requestedDate  Input string extracted from the request
+     * @param Bookmark|null $latestBookmark Latest bookmark found in the datastore (by date)
+     *
+     * @return DateTimeImmutable from input or latest bookmark.
+     *
+     * @throws Exception Type not supported.
+     */
+    public static function extractRequestedDateTime(
+        string $type,
+        ?string $requestedDate,
+        Bookmark $latestBookmark = null
+    ): DateTimeImmutable {
+        $format = static::getFormatByType($type);
+        if (empty($requestedDate)) {
+            return $latestBookmark instanceof Bookmark
+                ? new DateTimeImmutable($latestBookmark->getCreated()->format(\DateTime::ATOM))
+                : new DateTimeImmutable()
+            ;
+        }
+        // W is not supported by createFromFormat...
+        if ($type === static::WEEK) {
+            return (new DateTimeImmutable())
+                ->setISODate((int) substr($requestedDate, 0, 4), (int) substr($requestedDate, 4, 2))
+            ;
+        }
+        return DateTimeImmutable::createFromFormat($format, $requestedDate);
+    }
+    /**
+     * Get the DateTime format used by provided type
+     * Examples:
+     *   - day: 20201016 (<year><month><day>)
+     *   - week: 202041 (<year><week number>)
+     *   - month: 202010 (<year><month>)
+     *
+     * @param string $type month/week/day
+     *
+     * @return string DateTime compatible format
+     *
+     * @see https://www.php.net/manual/en/datetime.format.php
+     *
+     * @throws Exception Type not supported.
+     */
+    public static function getFormatByType(string $type): string
+    {
+        switch ($type) {
+            case static::MONTH:
+                return 'Ym';
+            case static::WEEK:
+                return 'YW';
+            case static::DAY:
+                return 'Ymd';
+            default:
+                throw new Exception('Unsupported daily format type');
+        }
+    }
+    /**
+     * Get the first DateTime of the time period depending on given datetime and type.
+     * Note: DateTimeImmutable is required because we rely heavily on DateTime->modify() syntax
+     *       and we don't want to alter original datetime.
+     *
+     * @param string             $type      month/week/day
+     * @param DateTimeImmutable $requested DateTime extracted from request input
+     *                                      (should come from extractRequestedDateTime)
+     *
+     * @return \DateTimeInterface First DateTime of the time period
+     *
+     * @throws Exception Type not supported.
+     */
+    public static function getStartDateTimeByType(string $type, DateTimeImmutable $requested): \DateTimeInterface
+    {
+        switch ($type) {
+            case static::MONTH:
+                return $requested->modify('first day of this month midnight');
+            case static::WEEK:
+                return $requested->modify('Monday this week midnight');
+            case static::DAY:
+                return $requested->modify('Today midnight');
+            default:
+                throw new Exception('Unsupported daily format type');
+        }
+    }
+    /**
+     * Get the last DateTime of the time period depending on given datetime and type.
+     * Note: DateTimeImmutable is required because we rely heavily on DateTime->modify() syntax
+     *       and we don't want to alter original datetime.
+     *
+     * @param string             $type      month/week/day
+     * @param DateTimeImmutable $requested DateTime extracted from request input
+     *                                      (should come from extractRequestedDateTime)
+     *
+     * @return \DateTimeInterface Last DateTime of the time period
+     *
+     * @throws Exception Type not supported.
+     */
+    public static function getEndDateTimeByType(string $type, DateTimeImmutable $requested): \DateTimeInterface
+    {
+        switch ($type) {
+            case static::MONTH:
+                return $requested->modify('last day of this month 23:59:59');
+            case static::WEEK:
+                return $requested->modify('Sunday this week 23:59:59');
+            case static::DAY:
+                return $requested->modify('Today 23:59:59');
+            default:
+                throw new Exception('Unsupported daily format type');
+        }
+    }
+    /**
+     * Get localized description of the time period depending on given datetime and type.
+     * Example: for a month period, it returns `October, 2020`.
+     *
+     * @param string             $type            month/week/day
+     * @param \DateTimeImmutable $requested       DateTime extracted from request input
+     *                                            (should come from extractRequestedDateTime)
+     * @param bool               $includeRelative Include relative date description (today, yesterday, etc.)
+     *
+     * @return string Localized time period description
+     *
+     * @throws Exception Type not supported.
+     */
+    public static function getDescriptionByType(
+        string $type,
+        \DateTimeImmutable $requested,
+        bool $includeRelative = true
+    ): string {
+        switch ($type) {
+            case static::MONTH:
+                return $requested->format('F') . ', ' . $requested->format('Y');
+            case static::WEEK:
+                $requested = $requested->modify('Monday this week');
+                return t('Week') . ' ' . $requested->format('W') . ' (' . format_date($requested, false) . ')';
+            case static::DAY:
+                $out = '';
+                if ($includeRelative && $requested->format('Ymd') === date('Ymd')) {
+                    $out = t('Today') . ' - ';
+                } elseif ($includeRelative && $requested->format('Ymd') === date('Ymd', strtotime('-1 days'))) {
+                    $out = t('Yesterday') . ' - ';
+                }
+                return $out . format_date($requested, false);
+            default:
+                throw new Exception('Unsupported daily format type');
+        }
+    }
+    /**
+     * Get the number of items to display in the RSS feed depending on the given type.
+     *
+     * @param string $type month/week/day
+     *
+     * @return int number of elements
+     *
+     * @throws Exception Type not supported.
+     */
+    public static function getRssLengthByType(string $type): int
+    {
+        switch ($type) {
+            case static::MONTH:
+                return 12; // 1 year
+            case static::WEEK:
+                return 26; // ~6 months
+            case static::DAY:
+                return 30; // ~1 month
+            default:
+                throw new Exception('Unsupported daily format type');
+        }
+    }
+    /**
+     * Get the number of items to display in the RSS feed depending on the given type.
+     *
+     * @param string             $type      month/week/day
+     * @param ?DateTimeImmutable $requested Currently only used for UT
+     *
+     * @return DatePeriod number of elements
+     *
+     * @throws Exception Type not supported.
+     */
+    public static function getCacheDatePeriodByType(string $type, DateTimeImmutable $requested = null): DatePeriod
+    {
+        $requested = $requested ?? new DateTimeImmutable();
+        return new DatePeriod(
+            static::getStartDateTimeByType($type, $requested),
+            new \DateInterval('P1D'),
+            static::getEndDateTimeByType($type, $requested)
+        );
+    }
+}
diff --git a/application/FileUtils.php b/application/helper/FileUtils.php
index 30560bfc..e8a2168c 100644
--- a/application/FileUtils.php
+++ b/application/helper/FileUtils.php
@@ -1,6 +1,6 @@
 <?php
-namespace Shaarli;
+namespace Shaarli\Helper;
 use Shaarli\Exceptions\IOException;
@@ -81,4 +81,60 @@ class FileUtils
            )
        );
    }
+    /**
+     * Recursively deletes a folder content, and deletes itself optionally.
+     * If an excluded file is found, folders won't be deleted.
+     *
+     * Additional security: raise an exception if it tries to delete a folder outside of Shaarli directory.
+     *
+     * @param string $path
+     * @param bool $selfDelete Delete the provided folder if true, only its content if false.
+     * @param array $exclude
+     */
+    public static function clearFolder(string $path, bool $selfDelete, array $exclude = []): bool
+    {
+        $skipped = false;
+        if (!is_dir($path)) {
+            throw new IOException(t('Provided path is not a directory.'));
+        }
+        if (!static::isPathInShaarliFolder($path)) {
+            throw new IOException(t('Trying to delete a folder outside of Shaarli path.'));
+        }
+        foreach (new \DirectoryIterator($path) as $file) {
+            if ($file->isDot()) {
+                continue;
+            }
+            if (in_array($file->getBasename(), $exclude, true)) {
+                $skipped = true;
+                continue;
+            }
+            if ($file->isFile()) {
+                unlink($file->getPathname());
+            } elseif ($file->isDir()) {
+                $skipped = static::clearFolder($file->getRealPath(), true, $exclude) || $skipped;
+            }
+        }
+        if ($selfDelete && !$skipped) {
+            rmdir($path);
+        }
+        return $skipped;
+    }
+    /**
+     * Checks that the given path is inside Shaarli directory.
+     */
+    public static function isPathInShaarliFolder(string $path): bool
+    {
+        $rootDirectory = dirname(dirname(dirname(__FILE__)));
+        return strpos(realpath($path), $rootDirectory) !== false;
+    }
 }
diff --git a/application/http/HttpAccess.php b/application/http/HttpAccess.php
index 81d9e076..e80e0c01 100644
--- a/application/http/HttpAccess.php
+++ b/application/http/HttpAccess.php
@@ -14,9 +14,14 @@ namespace Shaarli\Http;
 */
 class HttpAccess
 {
-    public function getHttpResponse($url, $timeout = 30, $maxBytes = 4194304, $curlWriteFunction = null)
+    public function getHttpResponse(
-    {
+        $url,
-        return get_http_response($url, $timeout, $maxBytes, $curlWriteFunction);
+        $timeout = 30,
+        $maxBytes = 4194304,
+        $curlHeaderFunction = null,
+        $curlWriteFunction = null
+    ) {
+        return get_http_response($url, $timeout, $maxBytes, $curlHeaderFunction, $curlWriteFunction);
    }
    public function getCurlDownloadCallback(
@@ -25,7 +30,7 @@ class HttpAccess
        &$description,
        &$keywords,
        $retrieveDescription,
-        $curlGetInfo = 'curl_getinfo'
+        $tagsSeparator
    ) {
        return get_curl_download_callback(
            $charset,
@@ -33,7 +38,12 @@ class HttpAccess
            $description,
            $keywords,
            $retrieveDescription,
-            $curlGetInfo
+            $tagsSeparator
        );
    }
+    public function getCurlHeaderCallback(&$charset, $curlGetInfo = 'curl_getinfo')
+    {
+        return get_curl_header_callback($charset, $curlGetInfo);
+    }
 }
diff --git a/application/http/HttpUtils.php b/application/http/HttpUtils.php
index 9f414073..4bde1d5b 100644
--- a/application/http/HttpUtils.php
+++ b/application/http/HttpUtils.php
@@ -6,12 +6,14 @@ use Shaarli\Http\Url;
 * GET an HTTP URL to retrieve its content
 * Uses the cURL library or a fallback method
 *
- * @param string          $url               URL to get (http://...)
+ * @param string          $url                URL to get (http://...)
- * @param int             $timeout           network timeout (in seconds)
+ * @param int             $timeout            network timeout (in seconds)
- * @param int             $maxBytes          maximum downloaded bytes (default: 4 MiB)
+ * @param int             $maxBytes           maximum downloaded bytes (default: 4 MiB)
- * @param callable|string $curlWriteFunction Optional callback called during the download (cURL CURLOPT_WRITEFUNCTION).
+ * @param callable|string $curlHeaderFunction Optional callback called during the download of headers
- *                                           Can be used to add download conditions on the
+ *                                            (CURLOPT_HEADERFUNCTION)
- *                                           headers (response code, content type, etc.).
+ * @param callable|string $curlWriteFunction  Optional callback called during the download (cURL CURLOPT_WRITEFUNCTION).
+ *                                            Can be used to add download conditions on the
+ *                                            headers (response code, content type, etc.).
 *
 * @return array HTTP response headers, downloaded content
 *
@@ -35,13 +37,18 @@ use Shaarli\Http\Url;
 * @see http://stackoverflow.com/q/9183178
 * @see http://stackoverflow.com/q/1462720
 */
-function get_http_response($url, $timeout = 30, $maxBytes = 4194304, $curlWriteFunction = null)
+function get_http_response(
-{
+    $url,
+    $timeout = 30,
+    $maxBytes = 4194304,
+    $curlHeaderFunction = null,
+    $curlWriteFunction = null
+) {
    $urlObj = new Url($url);
    $cleanUrl = $urlObj->idnToAscii();
    if (!filter_var($cleanUrl, FILTER_VALIDATE_URL) || !$urlObj->isHttp()) {
-        return array(array(0 => 'Invalid HTTP UrlUtils'), false);
+        return [[0 => 'Invalid HTTP UrlUtils'], false];
    }
    $userAgent =
@@ -64,42 +71,39 @@ function get_http_response($url, $timeout = 30, $maxBytes = 4194304, $curlWriteF
    $ch = curl_init($cleanUrl);
    if ($ch === false) {
-        return array(array(0 => 'curl_init() error'), false);
+        return [[0 => 'curl_init() error'], false];
    }
    // General cURL settings
    curl_setopt($ch, CURLOPT_AUTOREFERER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
-    curl_setopt($ch, CURLOPT_HEADER, true);
+    // Default header download if the $curlHeaderFunction is not defined
+    curl_setopt($ch, CURLOPT_HEADER, !is_callable($curlHeaderFunction));
    curl_setopt(
        $ch,
        CURLOPT_HTTPHEADER,
-        array('Accept-Language: ' . $acceptLanguage)
+        ['Accept-Language: ' . $acceptLanguage]
    );
    curl_setopt($ch, CURLOPT_MAXREDIRS, $maxRedirs);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
    curl_setopt($ch, CURLOPT_USERAGENT, $userAgent);
+    // Max download size management
+    curl_setopt($ch, CURLOPT_BUFFERSIZE, 1024 * 16);
+    curl_setopt($ch, CURLOPT_NOPROGRESS, false);
+    if (is_callable($curlHeaderFunction)) {
+        curl_setopt($ch, CURLOPT_HEADERFUNCTION, $curlHeaderFunction);
+    }
    if (is_callable($curlWriteFunction)) {
        curl_setopt($ch, CURLOPT_WRITEFUNCTION, $curlWriteFunction);
    }
-    // Max download size management
-    curl_setopt($ch, CURLOPT_BUFFERSIZE, 1024*16);
-    curl_setopt($ch, CURLOPT_NOPROGRESS, false);
    curl_setopt(
        $ch,
        CURLOPT_PROGRESSFUNCTION,
-        function ($arg0, $arg1, $arg2, $arg3, $arg4 = 0) use ($maxBytes) {
+        function ($arg0, $arg1, $arg2, $arg3, $arg4) use ($maxBytes) {
-            if (version_compare(phpversion(), '5.5', '<')) {
+            $downloaded = $arg2;
-                // PHP version lower than 5.5
-                // Callback has 4 arguments
-                $downloaded = $arg1;
-            } else {
-                // Callback has 5 arguments
-                $downloaded = $arg2;
-            }
            // Non-zero return stops downloading
            return ($downloaded > $maxBytes) ? 1 : 0;
        }
@@ -118,9 +122,9 @@ function get_http_response($url, $timeout = 30, $maxBytes = 4194304, $curlWriteF
             * Removing this would require updating
             * GetHttpUrlTest::testGetInvalidRemoteUrl()
             */
-            return array(false, false);
+            return [false, false];
        }
-        return array(array(0 => 'curl_exec() error: ' . $errorStr), false);
+        return [[0 => 'curl_exec() error: ' . $errorStr], false];
    }
    // Formatting output like the fallback method
@@ -131,7 +135,7 @@ function get_http_response($url, $timeout = 30, $maxBytes = 4194304, $curlWriteF
    $rawHeadersLastRedir = end($rawHeadersArrayRedirs);
    $content = substr($response, $headSize);
-    $headers = array();
+    $headers = [];
    foreach (preg_split('~[\r\n]+~', $rawHeadersLastRedir) as $line) {
        if (empty($line) || ctype_space($line)) {
            continue;
@@ -142,7 +146,7 @@ function get_http_response($url, $timeout = 30, $maxBytes = 4194304, $curlWriteF
            $value = $splitLine[1];
            if (array_key_exists($key, $headers)) {
                if (!is_array($headers[$key])) {
-                    $headers[$key] = array(0 => $headers[$key]);
+                    $headers[$key] = [0 => $headers[$key]];
                }
                $headers[$key][] = $value;
            } else {
@@ -153,7 +157,7 @@ function get_http_response($url, $timeout = 30, $maxBytes = 4194304, $curlWriteF
        }
    }
-    return array($headers, $content);
+    return [$headers, $content];
 }
 /**
@@ -184,15 +188,15 @@ function get_http_response_fallback(
    $acceptLanguage,
    $maxRedr
 ) {
-    $options = array(
+    $options = [
-        'http' => array(
+        'http' => [
            'method' => 'GET',
            'timeout' => $timeout,
            'user_agent' => $userAgent,
            'header' => "Accept: */*\r\n"
                . 'Accept-Language: ' . $acceptLanguage
-        )
+        ]
-    );
+    ];
    stream_context_set_default($options);
    list($headers, $finalUrl) = get_redirected_headers($cleanUrl, $maxRedr);
@@ -203,7 +207,7 @@ function get_http_response_fallback(
    }
    if (! $headers) {
-        return array($headers, false);
+        return [$headers, false];
    }
    try {
@@ -211,10 +215,10 @@ function get_http_response_fallback(
        $context = stream_context_create($options);
        $content = file_get_contents($finalUrl, false, $context, -1, $maxBytes);
    } catch (Exception $exc) {
-        return array(array(0 => 'HTTP Error'), $exc->getMessage());
+        return [[0 => 'HTTP Error'], $exc->getMessage()];
    }
-    return array($headers, $content);
+    return [$headers, $content];
 }
 /**
@@ -233,10 +237,12 @@ function get_redirected_headers($url, $redirectionLimit = 3)
    }
    // Headers found, redirection found, and limit not reached.
-    if ($redirectionLimit-- > 0
+    if (
+        $redirectionLimit-- > 0
        && !empty($headers)
        && (strpos($headers[0], '301') !== false || strpos($headers[0], '302') !== false)
-        && !empty($headers['Location'])) {
+        && !empty($headers['Location'])
+    ) {
        $redirection = is_array($headers['Location']) ? end($headers['Location']) : $headers['Location'];
        if ($redirection != $url) {
            $redirection = getAbsoluteUrl($url, $redirection);
@@ -244,7 +250,7 @@ function get_redirected_headers($url, $redirectionLimit = 3)
        }
    }
-    return array($headers, $url);
+    return [$headers, $url];
 }
 /**
@@ -266,7 +272,7 @@ function getAbsoluteUrl($originalUrl, $newUrl)
    }
    $parts = parse_url($originalUrl);
-    $final = $parts['scheme'] .'://'. $parts['host'];
+    $final = $parts['scheme'] . '://' . $parts['host'];
    $final .= (!empty($parts['port'])) ? $parts['port'] : '';
    $final .= '/';
    if ($newUrl[0] != '/') {
@@ -319,7 +325,8 @@ function server_url($server)
                $scheme = 'https';
            }
-            if (($scheme == 'http' && $port != '80')
+            if (
+                ($scheme == 'http' && $port != '80')
                || ($scheme == 'https' && $port != '443')
            ) {
                $port = ':' . $port;
@@ -340,22 +347,26 @@ function server_url($server)
            $host = $server['SERVER_NAME'];
        }
-        return $scheme.'://'.$host.$port;
+        return $scheme . '://' . $host . $port;
    }
    // SSL detection
-    if ((! empty($server['HTTPS']) && strtolower($server['HTTPS']) == 'on')
+    if (
-        || (isset($server['SERVER_PORT']) && $server['SERVER_PORT'] == '443')) {
+        (! empty($server['HTTPS']) && strtolower($server['HTTPS']) == 'on')
+        || (isset($server['SERVER_PORT']) && $server['SERVER_PORT'] == '443')
+    ) {
        $scheme = 'https';
    }
    // Do not append standard port values
-    if (($scheme == 'http' && $server['SERVER_PORT'] != '80')
+    if (
-        || ($scheme == 'https' && $server['SERVER_PORT'] != '443')) {
+        ($scheme == 'http' && $server['SERVER_PORT'] != '80')
-        $port = ':'.$server['SERVER_PORT'];
+        || ($scheme == 'https' && $server['SERVER_PORT'] != '443')
+    ) {
+        $port = ':' . $server['SERVER_PORT'];
    }
-    return $scheme.'://'.$server['SERVER_NAME'].$port;
+    return $scheme . '://' . $server['SERVER_NAME'] . $port;
 }
 /**
@@ -493,6 +504,46 @@ function is_https($server)
 * Get cURL callback function for CURLOPT_WRITEFUNCTION
 *
 * @param string $charset     to extract from the downloaded page (reference)
+ * @param string $curlGetInfo Optionally overrides curl_getinfo function
+ *
+ * @return Closure
+ */
+function get_curl_header_callback(
+    &$charset,
+    $curlGetInfo = 'curl_getinfo'
+) {
+    $isRedirected = false;
+    return function ($ch, $data) use ($curlGetInfo, &$charset, &$isRedirected) {
+        $responseCode = $curlGetInfo($ch, CURLINFO_RESPONSE_CODE);
+        $chunkLength = strlen($data);
+        if (!empty($responseCode) && in_array($responseCode, [301, 302])) {
+            $isRedirected = true;
+            return $chunkLength;
+        }
+        if (!empty($responseCode) && $responseCode !== 200) {
+            return false;
+        }
+        // After a redirection, the content type will keep the previous request value
+        // until it finds the next content-type header.
+        if (! $isRedirected || strpos(strtolower($data), 'content-type') !== false) {
+            $contentType = $curlGetInfo($ch, CURLINFO_CONTENT_TYPE);
+        }
+        if (!empty($contentType) && strpos($contentType, 'text/html') === false) {
+            return false;
+        }
+        if (!empty($contentType) && empty($charset)) {
+            $charset = header_extract_charset($contentType);
+        }
+        return $chunkLength;
+    };
+}
+/**
+ * Get cURL callback function for CURLOPT_WRITEFUNCTION
+ *
+ * @param string $charset     to extract from the downloaded page (reference)
 * @param string $title       to extract from the downloaded page (reference)
 * @param string $description to extract from the downloaded page (reference)
 * @param string $keywords    to extract from the downloaded page (reference)
@@ -507,9 +558,8 @@ function get_curl_download_callback(
    &$description,
    &$keywords,
    $retrieveDescription,
-    $curlGetInfo = 'curl_getinfo'
+    $tagsSeparator
 ) {
-    $isRedirected = false;
    $currentChunk = 0;
    $foundChunk = null;
@@ -524,37 +574,22 @@ function get_curl_download_callback(
     *
     * @return int|bool length of $data or false if we need to stop the download
     */
-    return function (&$ch, $data) use (
+    return function (
+        $ch,
+        $data
+    ) use (
        $retrieveDescription,
-        $curlGetInfo,
+        $tagsSeparator,
        &$charset,
        &$title,
        &$description,
        &$keywords,
-        &$isRedirected,
        &$currentChunk,
        &$foundChunk
    ) {
+        $chunkLength = strlen($data);
        $currentChunk++;
-        $responseCode = $curlGetInfo($ch, CURLINFO_RESPONSE_CODE);
-        if (!empty($responseCode) && in_array($responseCode, [301, 302])) {
-            $isRedirected = true;
-            return strlen($data);
-        }
-        if (!empty($responseCode) && $responseCode !== 200) {
-            return false;
-        }
-        // After a redirection, the content type will keep the previous request value
-        // until it finds the next content-type header.
-        if (! $isRedirected || strpos(strtolower($data), 'content-type') !== false) {
-            $contentType = $curlGetInfo($ch, CURLINFO_CONTENT_TYPE);
-        }
-        if (!empty($contentType) && strpos($contentType, 'text/html') === false) {
-            return false;
-        }
-        if (!empty($contentType) && empty($charset)) {
-            $charset = header_extract_charset($contentType);
-        }
        if (empty($charset)) {
            $charset = html_extract_charset($data);
        }
@@ -562,6 +597,10 @@ function get_curl_download_callback(
            $title = html_extract_title($data);
            $foundChunk = ! empty($title) ? $currentChunk : $foundChunk;
        }
+        if (empty($title)) {
+            $title = html_extract_tag('title', $data);
+            $foundChunk = ! empty($title) ? $currentChunk : $foundChunk;
+        }
        if ($retrieveDescription && empty($description)) {
            $description = html_extract_tag('description', $data);
            $foundChunk = ! empty($description) ? $currentChunk : $foundChunk;
@@ -571,10 +610,10 @@ function get_curl_download_callback(
            if (! empty($keywords)) {
                $foundChunk = $currentChunk;
                // Keywords use the format tag1, tag2 multiple words, tag
-                // So we format them to match Shaarli's separator and glue multiple words with '-'
+                // So we split the result with `,`, then if a tag contains the separator we replace it by `-`.
-                $keywords = implode(' ', array_map(function($keyword) {
+                $keywords = tags_array2str(array_map(function (string $keyword) use ($tagsSeparator): string {
-                    return implode('-', preg_split('/\s+/', trim($keyword)));
+                    return tags_array2str(tags_str2array($keyword, $tagsSeparator), '-');
-                }, explode(',', $keywords)));
+                }, tags_str2array($keywords, ',')), $tagsSeparator);
            }
        }
@@ -582,7 +621,8 @@ function get_curl_download_callback(
        // If we already found either the title, description or keywords,
        // it's highly unlikely that we'll found the other metas further than
        // in the same chunk of data or the next one. So we also stop the download after that.
-        if ((!empty($responseCode) && !empty($contentType) && !empty($charset)) && $foundChunk !== null
+        if (
+            (!empty($responseCode) && !empty($contentType) && !empty($charset)) && $foundChunk !== null
            && (! $retrieveDescription
                || $foundChunk < $currentChunk
                || (!empty($title) && !empty($description) && !empty($keywords))
@@ -591,6 +631,6 @@ function get_curl_download_callback(
            return false;
        }
-        return strlen($data);
+        return $chunkLength;
    };
 }
diff --git a/application/http/MetadataRetriever.php b/application/http/MetadataRetriever.php
new file mode 100644
index 00000000..cfc72583
--- /dev/null
+++ b/application/http/MetadataRetriever.php
@@ -0,0 +1,74 @@
+<?php
+declare(strict_types=1);
+namespace Shaarli\Http;
+use Shaarli\Config\ConfigManager;
+/**
+ * HTTP Tool used to extract metadata from external URL (title, description, etc.).
+ */
+class MetadataRetriever
+{
+    /** @var ConfigManager */
+    protected $conf;
+    /** @var HttpAccess */
+    protected $httpAccess;
+    public function __construct(ConfigManager $conf, HttpAccess $httpAccess)
+    {
+        $this->conf = $conf;
+        $this->httpAccess = $httpAccess;
+    }
+    /**
+     * Retrieve metadata for given URL.
+     *
+     * @return array [
+     *                  'title' => <remote title>,
+     *                  'description' => <remote description>,
+     *                  'tags' => <remote keywords>,
+     *               ]
+     */
+    public function retrieve(string $url): array
+    {
+        $charset = null;
+        $title = null;
+        $description = null;
+        $tags = null;
+        // Short timeout to keep the application responsive
+        // The callback will fill $charset and $title with data from the downloaded page.
+        $this->httpAccess->getHttpResponse(
+            $url,
+            $this->conf->get('general.download_timeout', 30),
+            $this->conf->get('general.download_max_size', 4194304),
+            $this->httpAccess->getCurlHeaderCallback($charset),
+            $this->httpAccess->getCurlDownloadCallback(
+                $charset,
+                $title,
+                $description,
+                $tags,
+                $this->conf->get('general.retrieve_description'),
+                $this->conf->get('general.tags_separator', ' ')
+            )
+        );
+        if (!empty($title) && strtolower($charset) !== 'utf-8') {
+            $title = mb_convert_encoding($title, 'utf-8', $charset);
+        }
+        return array_map([$this, 'cleanMetadata'], [
+            'title' => $title,
+            'description' => $description,
+            'tags' => $tags,
+        ]);
+    }
+    protected function cleanMetadata($data): ?string
+    {
+        return !is_string($data) || empty(trim($data)) ? null : trim($data);
+    }
+}
diff --git a/application/http/Url.php b/application/http/Url.php
index 90444a2f..fe87088f 100644
--- a/application/http/Url.php
+++ b/application/http/Url.php
@@ -17,7 +17,7 @@ namespace Shaarli\Http;
 */
 class Url
 {
-    private static $annoyingQueryParams = array(
+    private static $annoyingQueryParams = [
        // Facebook
        'action_object_map=',
        'action_ref_map=',
@@ -37,15 +37,15 @@ class Url
        // Other
        'campaign_'
-    );
+    ];
-    private static $annoyingFragments = array(
+    private static $annoyingFragments = [
        // ATInternet
        'xtor=RSS-',
        // Misc.
        'tk.rss_all'
-    );
+    ];
    /*
     * URL parts represented as an array
@@ -120,7 +120,7 @@ class Url
        foreach (self::$annoyingQueryParams as $annoying) {
            foreach ($queryParams as $param) {
                if (startsWith($param, $annoying)) {
-                    $queryParams = array_diff($queryParams, array($param));
+                    $queryParams = array_diff($queryParams, [$param]);
                    continue;
                }
            }
diff --git a/application/http/UrlUtils.php b/application/http/UrlUtils.php
index e8d1a283..de5b7db1 100644
--- a/application/http/UrlUtils.php
+++ b/application/http/UrlUtils.php
@@ -1,4 +1,5 @@
 <?php
 /**
 * Converts an array-represented URL to a string
 *
@@ -12,15 +13,15 @@
 */
 function unparse_url($parsedUrl)
 {
-    $scheme   = isset($parsedUrl['scheme']) ? $parsedUrl['scheme'].'://' : '';
+    $scheme   = isset($parsedUrl['scheme']) ? $parsedUrl['scheme'] . '://' : '';
    $host     = isset($parsedUrl['host']) ? $parsedUrl['host'] : '';
-    $port     = isset($parsedUrl['port']) ? ':'.$parsedUrl['port'] : '';
+    $port     = isset($parsedUrl['port']) ? ':' . $parsedUrl['port'] : '';
    $user     = isset($parsedUrl['user']) ? $parsedUrl['user'] : '';
-    $pass     = isset($parsedUrl['pass']) ? ':'.$parsedUrl['pass']  : '';
+    $pass     = isset($parsedUrl['pass']) ? ':' . $parsedUrl['pass']  : '';
    $pass     = ($user || $pass) ? "$pass@" : '';
    $path     = isset($parsedUrl['path']) ? $parsedUrl['path'] : '';
-    $query    = isset($parsedUrl['query']) ? '?'.$parsedUrl['query'] : '';
+    $query    = isset($parsedUrl['query']) ? '?' . $parsedUrl['query'] : '';
-    $fragment = isset($parsedUrl['fragment']) ? '#'.$parsedUrl['fragment'] : '';
+    $fragment = isset($parsedUrl['fragment']) ? '#' . $parsedUrl['fragment'] : '';
    return "$scheme$user$pass$host$port$path$query$fragment";
 }
diff --git a/application/legacy/LegacyController.php b/application/legacy/LegacyController.php
index 826604e7..1fed418b 100644
--- a/application/legacy/LegacyController.php
+++ b/application/legacy/LegacyController.php
@@ -51,7 +51,7 @@ class LegacyController extends ShaarliVisitorController
        if (!$this->container->loginManager->isLoggedIn()) {
            $parameters = $buildParameters($request->getQueryParams(), true);
-            return $this->redirect($response, '/login?returnurl='. $this->getBasePath() . $route . $parameters);
+            return $this->redirect($response, '/login?returnurl=' . $this->getBasePath() . $route . $parameters);
        }
        $parameters = $buildParameters($request->getQueryParams(), false);
diff --git a/application/legacy/LegacyLinkDB.php b/application/legacy/LegacyLinkDB.php
index 7bf76fd4..d3beafe0 100644
--- a/application/legacy/LegacyLinkDB.php
+++ b/application/legacy/LegacyLinkDB.php
@@ -8,7 +8,7 @@ use DateTime;
 use Iterator;
 use Shaarli\Bookmark\Exception\BookmarkNotFoundException;
 use Shaarli\Exceptions\IOException;
-use Shaarli\FileUtils;
+use Shaarli\Helper\FileUtils;
 use Shaarli\Render\PageCacheManager;
 /**
@@ -62,7 +62,7 @@ class LegacyLinkDB implements Iterator, Countable, ArrayAccess
    private $datastore;
    // Link date storage format
-    const LINK_DATE_FORMAT = 'Ymd_His';
+    public const LINK_DATE_FORMAT = 'Ymd_His';
    // List of bookmarks (associative array)
    //  - key:   link date (e.g. "20110823_124546"),
@@ -240,8 +240,8 @@ class LegacyLinkDB implements Iterator, Countable, ArrayAccess
        }
        // Create a dummy database for example
-        $this->links = array();
+        $this->links = [];
-        $link = array(
+        $link = [
            'id' => 1,
            'title' => t('The personal, minimalist, super-fast, database free, bookmarking service'),
            'url' => 'https://shaarli.readthedocs.io',
@@ -257,11 +257,11 @@ You use the community supported version of the original Shaarli project, by Seba
            'created' => new DateTime(),
            'tags' => 'opensource software',
            'sticky' => false,
-        );
+        ];
        $link['shorturl'] = link_small_hash($link['created'], $link['id']);
        $this->links[1] = $link;
-        $link = array(
+        $link = [
            'id' => 0,
            'title' => t('My secret stuff... - Pastebin.com'),
            'url' => 'http://sebsauvage.net/paste/?8434b27936c09649#bR7XsXhoTiLcqCpQbmOpBi3rq2zzQUC5hBI7ZT1O3x8=',
@@ -270,7 +270,7 @@ You use the community supported version of the original Shaarli project, by Seba
            'created' => new DateTime('1 minute ago'),
            'tags' => 'secretstuff',
            'sticky' => false,
-        );
+        ];
        $link['shorturl'] = link_small_hash($link['created'], $link['id']);
        $this->links[0] = $link;
@@ -285,7 +285,7 @@ You use the community supported version of the original Shaarli project, by Seba
    {
        // Public bookmarks are hidden and user not logged in => nothing to show
        if ($this->hidePublicLinks && !$this->loggedIn) {
-            $this->links = array();
+            $this->links = [];
            return;
        }
@@ -293,7 +293,7 @@ You use the community supported version of the original Shaarli project, by Seba
        $this->ids = [];
        $this->links = FileUtils::readFlatDB($this->datastore, []);
-        $toremove = array();
+        $toremove = [];
        foreach ($this->links as $key => &$link) {
            if (!$this->loggedIn && $link['private'] != 0) {
                // Transition for not upgraded databases.
@@ -414,7 +414,7 @@ You use the community supported version of the original Shaarli project, by Seba
     * @return array filtered bookmarks, all bookmarks if no suitable filter was provided.
     */
    public function filterSearch(
-        $filterRequest = array(),
+        $filterRequest = [],
        $casesensitive = false,
        $visibility = 'all',
        $untaggedonly = false
@@ -512,7 +512,7 @@ You use the community supported version of the original Shaarli project, by Seba
     */
    public function days()
    {
-        $linkDays = array();
+        $linkDays = [];
        foreach ($this->links as $link) {
            $linkDays[$link['created']->format('Ymd')] = 0;
        }
diff --git a/application/legacy/LegacyLinkFilter.php b/application/legacy/LegacyLinkFilter.php
index 7cf93d60..e6d186c4 100644
--- a/application/legacy/LegacyLinkFilter.php
+++ b/application/legacy/LegacyLinkFilter.php
@@ -120,7 +120,7 @@ class LegacyLinkFilter
            return $this->links;
        }
-        $out = array();
+        $out = [];
        foreach ($this->links as $key => $value) {
            if ($value['private'] && $visibility === 'private') {
                $out[$key] = $value;
@@ -143,7 +143,7 @@ class LegacyLinkFilter
     */
    private function filterSmallHash($smallHash)
    {
-        $filtered = array();
+        $filtered = [];
        foreach ($this->links as $key => $l) {
            if ($smallHash == $l['shorturl']) {
                // Yes, this is ugly and slow
@@ -186,7 +186,7 @@ class LegacyLinkFilter
            return $this->noFilter($visibility);
        }
-        $filtered = array();
+        $filtered = [];
        $search = mb_convert_case(html_entity_decode($searchterms), MB_CASE_LOWER, 'UTF-8');
        $exactRegex = '/"([^"]+)"/';
        // Retrieve exact search terms.
@@ -198,8 +198,8 @@ class LegacyLinkFilter
        $explodedSearchAnd = array_values(array_filter($explodedSearchAnd));
        // Filter excluding terms and update andSearch.
-        $excludeSearch = array();
+        $excludeSearch = [];
-        $andSearch = array();
+        $andSearch = [];
        foreach ($explodedSearchAnd as $needle) {
            if ($needle[0] == '-' && strlen($needle) > 1) {
                $excludeSearch[] = substr($needle, 1);
@@ -208,7 +208,7 @@ class LegacyLinkFilter
            }
        }
-        $keys = array('title', 'description', 'url', 'tags');
+        $keys = ['title', 'description', 'url', 'tags'];
        // Iterate over every stored link.
        foreach ($this->links as $id => $link) {
@@ -336,7 +336,7 @@ class LegacyLinkFilter
        }
        // create resulting array
-        $filtered = array();
+        $filtered = [];
        // iterate over each link
        foreach ($this->links as $key => $link) {
@@ -352,7 +352,7 @@ class LegacyLinkFilter
            $search = $link['tags']; // build search string, start with tags of current link
            if (strlen(trim($link['description'])) && strpos($link['description'], '#') !== false) {
                // description given and at least one possible tag found
-                $descTags = array();
+                $descTags = [];
                // find all tags in the form of #tag in the description
                preg_match_all(
                    '/(?<![' . self::$HASHTAG_CHARS . '])#([' . self::$HASHTAG_CHARS . ']+?)\b/sm',
@@ -419,7 +419,7 @@ class LegacyLinkFilter
            throw new Exception('Invalid date format');
        }
-        $filtered = array();
+        $filtered = [];
        foreach ($this->links as $key => $l) {
            if ($l['created']->format('Ymd') == $day) {
                $filtered[$key] = $l;
diff --git a/application/legacy/LegacyUpdater.php b/application/legacy/LegacyUpdater.php
index 0ab3a55b..9bda54b8 100644
--- a/application/legacy/LegacyUpdater.php
+++ b/application/legacy/LegacyUpdater.php
@@ -7,7 +7,6 @@ use RainTPL;
 use ReflectionClass;
 use ReflectionException;
 use ReflectionMethod;
-use Shaarli\ApplicationUtils;
 use Shaarli\Bookmark\Bookmark;
 use Shaarli\Bookmark\BookmarkArray;
 use Shaarli\Bookmark\BookmarkFilter;
@@ -17,6 +16,7 @@ use Shaarli\Config\ConfigJson;
 use Shaarli\Config\ConfigManager;
 use Shaarli\Config\ConfigPhp;
 use Shaarli\Exceptions\IOException;
+use Shaarli\Helper\ApplicationUtils;
 use Shaarli\Thumbnailer;
 use Shaarli\Updater\Exception\UpdaterException;
@@ -93,7 +93,7 @@ class LegacyUpdater
     */
    public function update()
    {
-        $updatesRan = array();
+        $updatesRan = [];
        // If the user isn't logged in, exit without updating.
        if ($this->isLoggedIn !== true) {
@@ -106,7 +106,8 @@ class LegacyUpdater
        foreach ($this->methods as $method) {
            // Not an update method or already done, pass.
-            if (!startsWith($method->getName(), 'updateMethod')
+            if (
+                !startsWith($method->getName(), 'updateMethod')
                || in_array($method->getName(), $this->doneUpdates)
            ) {
                continue;
@@ -189,7 +190,7 @@ class LegacyUpdater
        }
        // Set sub config keys (config and plugins)
-        $subConfig = array('config', 'plugins');
+        $subConfig = ['config', 'plugins'];
        foreach ($subConfig as $sub) {
            foreach ($oldConfig[$sub] as $key => $value) {
                if (isset($legacyMap[$sub . '.' . $key])) {
@@ -259,7 +260,7 @@ class LegacyUpdater
        $save = $this->conf->get('resource.data_dir') . '/datastore.' . date('YmdHis') . '.php';
        copy($this->conf->get('resource.datastore'), $save);
-        $links = array();
+        $links = [];
        foreach ($this->linkDB as $offset => $value) {
            $links[] = $value;
            unset($this->linkDB[$offset]);
@@ -498,7 +499,8 @@ class LegacyUpdater
     */
    public function updateMethodDownloadSizeAndTimeoutConf()
    {
-        if ($this->conf->exists('general.download_max_size')
+        if (
+            $this->conf->exists('general.download_max_size')
            && $this->conf->exists('general.download_timeout')
        ) {
            return true;
@@ -585,7 +587,7 @@ class LegacyUpdater
        $linksArray = new BookmarkArray();
        foreach ($this->linkDB as $key => $link) {
-            $linksArray[$key] = (new Bookmark())->fromArray($link);
+            $linksArray[$key] = (new Bookmark())->fromArray($link, $this->conf->get('general.tags_separator', ' '));
        }
        $linksIo = new BookmarkIO($this->conf);
        $linksIo->write($linksArray);
diff --git a/application/netscape/NetscapeBookmarkUtils.php b/application/netscape/NetscapeBookmarkUtils.php
index b83f16f8..2d97b4c8 100644
--- a/application/netscape/NetscapeBookmarkUtils.php
+++ b/application/netscape/NetscapeBookmarkUtils.php
@@ -59,11 +59,11 @@ class NetscapeBookmarkUtils
        $indexUrl
    ) {
        // see tpl/export.html for possible values
-        if (!in_array($selection, array('all', 'public', 'private'))) {
+        if (!in_array($selection, ['all', 'public', 'private'])) {
            throw new Exception(t('Invalid export selection:') . ' "' . $selection . '"');
        }
-        $bookmarkLinks = array();
+        $bookmarkLinks = [];
        foreach ($this->bookmarkService->search([], $selection) as $bookmark) {
            $link = $formatter->format($bookmark);
            $link['taglist'] = implode(',', $bookmark->getTags());
@@ -101,11 +101,11 @@ class NetscapeBookmarkUtils
        // Add tags to all imported bookmarks?
        if (empty($post['default_tags'])) {
-            $defaultTags = array();
+            $defaultTags = [];
        } else {
-            $defaultTags = preg_split(
+            $defaultTags = tags_str2array(
-                '/[\s,]+/',
+                escape($post['default_tags']),
-                escape($post['default_tags'])
+                $this->conf->get('general.tags_separator', ' ')
            );
        }
@@ -171,7 +171,7 @@ class NetscapeBookmarkUtils
            $link->setUrl($bkm['uri'], $this->conf->get('security.allowed_protocols'));
            $link->setDescription($bkm['note']);
            $link->setPrivate($private);
-            $link->setTagsString($bkm['tags']);
+            $link->setTags($bkm['tags']);
            $this->bookmarkService->addOrSet($link, false);
            $importCount++;
diff --git a/application/plugin/PluginManager.php b/application/plugin/PluginManager.php
index da66dea3..7fc0cb04 100644
--- a/application/plugin/PluginManager.php
+++ b/application/plugin/PluginManager.php
@@ -1,8 +1,10 @@
 <?php
 namespace Shaarli\Plugin;
 use Shaarli\Config\ConfigManager;
 use Shaarli\Plugin\Exception\PluginFileNotFoundException;
+use Shaarli\Plugin\Exception\PluginInvalidRouteException;
 /**
 * Class PluginManager
@@ -23,7 +25,15 @@ class PluginManager
     *
     * @var array $loadedPlugins
     */
-    private $loadedPlugins = array();
+    private $loadedPlugins = [];
+    /** @var array List of registered routes. Contains keys:
+     *               - `method`: HTTP method, GET/POST/PUT/PATCH/DELETE
+     *               - `route` (path): without prefix, e.g. `/up/{variable}`
+     *                 It will be later prefixed by `/plugin/<plugin name>/`.
+     *               - `callable` string, function name or FQN class's method, e.g. `demo_plugin_custom_controller`.
+     */
+    protected $registeredRoutes = [];
    /**
     * @var ConfigManager Configuration Manager instance.
@@ -57,7 +67,7 @@ class PluginManager
    public function __construct(&$conf)
    {
        $this->conf = $conf;
-        $this->errors = array();
+        $this->errors = [];
    }
    /**
@@ -85,6 +95,9 @@ class PluginManager
                $this->loadPlugin($dirs[$index], $plugin);
            } catch (PluginFileNotFoundException $e) {
                error_log($e->getMessage());
+            } catch (\Throwable $e) {
+                $error = $plugin . t(' [plugin incompatibility]: ') . $e->getMessage();
+                $this->errors = array_unique(array_merge($this->errors, [$error]));
            }
        }
    }
@@ -98,7 +111,7 @@ class PluginManager
     *
     * @return void
     */
-    public function executeHooks($hook, &$data, $params = array())
+    public function executeHooks($hook, &$data, $params = [])
    {
        $metadataParameters = [
            'target' => '_PAGE_',
@@ -165,6 +178,22 @@ class PluginManager
            }
        }
+        $registerRouteFunction = $pluginName . '_register_routes';
+        $routes = null;
+        if (function_exists($registerRouteFunction)) {
+            $routes = call_user_func($registerRouteFunction);
+        }
+        if ($routes !== null) {
+            foreach ($routes as $route) {
+                if (static::validateRouteRegistration($route)) {
+                    $this->registeredRoutes[$pluginName][] = $route;
+                } else {
+                    throw new PluginInvalidRouteException($pluginName);
+                }
+            }
+        }
        $this->loadedPlugins[] = $pluginName;
    }
@@ -196,7 +225,7 @@ class PluginManager
     */
    public function getPluginsMeta()
    {
-        $metaData = array();
+        $metaData = [];
        $dirs = glob(self::$PLUGINS_PATH . '/*', GLOB_ONLYDIR | GLOB_MARK);
        // Browse all plugin directories.
@@ -217,9 +246,9 @@ class PluginManager
            if (isset($metaData[$plugin]['parameters'])) {
                $params = explode(';', $metaData[$plugin]['parameters']);
            } else {
-                $params = array();
+                $params = [];
            }
-            $metaData[$plugin]['parameters'] = array();
+            $metaData[$plugin]['parameters'] = [];
            foreach ($params as $param) {
                if (empty($param)) {
                    continue;
@@ -237,6 +266,14 @@ class PluginManager
    }
    /**
+     * @return array List of registered custom routes by plugins.
+     */
+    public function getRegisteredRoutes(): array
+    {
+        return $this->registeredRoutes;
+    }
+    /**
     * Return the list of encountered errors.
     *
     * @return array List of errors (empty array if none exists).
@@ -245,4 +282,32 @@ class PluginManager
    {
        return $this->errors;
    }
+    /**
+     * Checks whether provided input is valid to register a new route.
+     * It must contain keys `method`, `route`, `callable` (all strings).
+     *
+     * @param string[] $input
+     *
+     * @return bool
+     */
+    protected static function validateRouteRegistration(array $input): bool
+    {
+        if (
+            !array_key_exists('method', $input)
+            || !in_array(strtoupper($input['method']), ['GET', 'PUT', 'PATCH', 'POST', 'DELETE'])
+        ) {
+            return false;
+        }
+        if (!array_key_exists('route', $input) || !preg_match('#^[a-z\d/\.\-_]+$#', $input['route'])) {
+            return false;
+        }
+        if (!array_key_exists('callable', $input)) {
+            return false;
+        }
+        return true;
+    }
 }
diff --git a/application/plugin/exception/PluginFileNotFoundException.php b/application/plugin/exception/PluginFileNotFoundException.php
index e5386f02..21ac6604 100644
--- a/application/plugin/exception/PluginFileNotFoundException.php
+++ b/application/plugin/exception/PluginFileNotFoundException.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Plugin\Exception;
 use Exception;
diff --git a/application/plugin/exception/PluginInvalidRouteException.php b/application/plugin/exception/PluginInvalidRouteException.php
new file mode 100644
index 00000000..6ba9bc43
--- /dev/null
+++ b/application/plugin/exception/PluginInvalidRouteException.php
@@ -0,0 +1,26 @@
+<?php
+declare(strict_types=1);
+namespace Shaarli\Plugin\Exception;
+use Exception;
+/**
+ * Class PluginFileNotFoundException
+ *
+ * Raise when plugin files can't be found.
+ */
+class PluginInvalidRouteException extends Exception
+{
+    /**
+     * Construct exception with plugin name.
+     * Generate message.
+     *
+     * @param string $pluginName name of the plugin not found
+     */
+    public function __construct()
+    {
+        $this->message = 'trying to register invalid route.';
+    }
+}
diff --git a/application/render/PageBuilder.php b/application/render/PageBuilder.php
index 2d6d2dbe..bf0ae326 100644
--- a/application/render/PageBuilder.php
+++ b/application/render/PageBuilder.php
@@ -3,11 +3,11 @@
 namespace Shaarli\Render;
 use Exception;
-use exceptions\MissingBasePathException;
+use Psr\Log\LoggerInterface;
 use RainTPL;
-use Shaarli\ApplicationUtils;
 use Shaarli\Bookmark\BookmarkServiceInterface;
 use Shaarli\Config\ConfigManager;
+use Shaarli\Helper\ApplicationUtils;
 use Shaarli\Security\SessionManager;
 use Shaarli\Thumbnailer;
@@ -35,6 +35,9 @@ class PageBuilder
     */
    protected $session;
+    /** @var LoggerInterface */
+    protected $logger;
    /**
     * @var BookmarkServiceInterface $bookmarkService instance.
     */
@@ -54,17 +57,25 @@ class PageBuilder
     * PageBuilder constructor.
     * $tpl is initialized at false for lazy loading.
     *
-     * @param ConfigManager            $conf    Configuration Manager instance (reference).
+     * @param ConfigManager $conf Configuration Manager instance (reference).
-     * @param array                    $session $_SESSION array
+     * @param array $session $_SESSION array
-     * @param BookmarkServiceInterface $linkDB  instance.
+     * @param LoggerInterface $logger
-     * @param string                   $token   Session token
+     * @param null $linkDB instance.
-     * @param bool                     $isLoggedIn
+     * @param null $token Session token
+     * @param bool $isLoggedIn
     */
-    public function __construct(&$conf, $session, $linkDB = null, $token = null, $isLoggedIn = false)
+    public function __construct(
-    {
+        ConfigManager &$conf,
+        array $session,
+        LoggerInterface $logger,
+        $linkDB = null,
+        $token = null,
+        $isLoggedIn = false
+    ) {
        $this->tpl = false;
        $this->conf = $conf;
        $this->session = $session;
+        $this->logger = $logger;
        $this->bookmarkService = $linkDB;
        $this->token = $token;
        $this->isLoggedIn = $isLoggedIn;
@@ -98,7 +109,7 @@ class PageBuilder
            $this->tpl->assign('newVersion', escape($version));
            $this->tpl->assign('versionError', '');
        } catch (Exception $exc) {
-            logm($this->conf->get('resource.log'), $_SERVER['REMOTE_ADDR'], $exc->getMessage());
+            $this->logger->error(format_log('Error: ' . $exc->getMessage(), client_ip_id($_SERVER)));
            $this->tpl->assign('newVersion', '');
            $this->tpl->assign('versionError', escape($exc->getMessage()));
        }
@@ -149,7 +160,8 @@ class PageBuilder
        $this->tpl->assign('formatter', $this->conf->get('formatter', 'default'));
-        $this->tpl->assign('links_per_page', $this->session['LINKS_PER_PAGE']);
+        $this->tpl->assign('links_per_page', $this->session['LINKS_PER_PAGE'] ?? 20);
+        $this->tpl->assign('tags_separator', $this->conf->get('general.tags_separator', ' '));
        // To be removed with a proper theme configuration.
        $this->tpl->assign('conf', $this->conf);
diff --git a/application/render/PageCacheManager.php b/application/render/PageCacheManager.php
index 97805c35..fe74bf27 100644
--- a/application/render/PageCacheManager.php
+++ b/application/render/PageCacheManager.php
@@ -2,6 +2,7 @@
 namespace Shaarli\Render;
+use DatePeriod;
 use Shaarli\Feed\CachedPage;
 /**
@@ -49,12 +50,21 @@ class PageCacheManager
        $this->purgeCachedPages();
    }
-    public function getCachePage(string $pageUrl): CachedPage
+    /**
+     * Get CachedPage instance for provided URL.
+     *
+     * @param string      $pageUrl
+     * @param ?DatePeriod $validityPeriod Optionally specify a time limit on requested cache
+     *
+     * @return CachedPage
+     */
+    public function getCachePage(string $pageUrl, DatePeriod $validityPeriod = null): CachedPage
    {
        return new CachedPage(
            $this->pageCacheDir,
            $pageUrl,
-            false === $this->isLoggedIn
+            false === $this->isLoggedIn,
+            $validityPeriod
        );
    }
 }
diff --git a/application/render/TemplatePage.php b/application/render/TemplatePage.php
index 8af8228a..03b424f3 100644
--- a/application/render/TemplatePage.php
+++ b/application/render/TemplatePage.php
@@ -14,6 +14,7 @@ interface TemplatePage
    public const DAILY = 'daily';
    public const DAILY_RSS = 'dailyrss';
    public const EDIT_LINK = 'editlink';
+    public const EDIT_LINK_BATCH = 'editlink.batch';
    public const ERROR = 'error';
    public const EXPORT = 'export';
    public const NETSCAPE_EXPORT_BOOKMARKS = 'export.bookmarks';
diff --git a/application/render/ThemeUtils.php b/application/render/ThemeUtils.php
index 86096c64..18471f0a 100644
--- a/application/render/ThemeUtils.php
+++ b/application/render/ThemeUtils.php
@@ -23,10 +23,10 @@ class ThemeUtils
    public static function getThemes($tplDir)
    {
        $tplDir = rtrim($tplDir, '/');
-        $allTheme = glob($tplDir.'/*', GLOB_ONLYDIR);
+        $allTheme = glob($tplDir . '/*', GLOB_ONLYDIR);
        $themes = [];
        foreach ($allTheme as $value) {
-            $themes[] = str_replace($tplDir.'/', '', $value);
+            $themes[] = str_replace($tplDir . '/', '', $value);
        }
        return $themes;
diff --git a/application/security/BanManager.php b/application/security/BanManager.php
index 68190c54..7077af5b 100644
--- a/application/security/BanManager.php
+++ b/application/security/BanManager.php
@@ -1,9 +1,9 @@
 <?php
 namespace Shaarli\Security;
-use Shaarli\FileUtils;
+use Psr\Log\LoggerInterface;
+use Shaarli\Helper\FileUtils;
 /**
 * Class BanManager
@@ -28,8 +28,8 @@ class BanManager
    /** @var string Path to the file containing IP bans and failures */
    protected $banFile;
-    /** @var string Path to the log file, used to log bans */
+    /** @var LoggerInterface Path to the log file, used to log bans */
-    protected $logFile;
+    protected $logger;
    /** @var array List of IP with their associated number of failed attempts */
    protected $failures = [];
@@ -40,18 +40,20 @@ class BanManager
    /**
     * BanManager constructor.
     *
-     * @param array  $trustedProxies List of allowed proxies IP
+     * @param array           $trustedProxies List of allowed proxies IP
-     * @param int    $nbAttempts     Number of allowed failed attempt before the ban
+     * @param int             $nbAttempts     Number of allowed failed attempt before the ban
-     * @param int    $banDuration    Ban duration in seconds
+     * @param int             $banDuration    Ban duration in seconds
-     * @param string $banFile        Path to the file containing IP bans and failures
+     * @param string          $banFile        Path to the file containing IP bans and failures
-     * @param string $logFile        Path to the log file, used to log bans
+     * @param LoggerInterface $logger         PSR-3 logger to save login attempts in log directory
     */
-    public function __construct($trustedProxies, $nbAttempts, $banDuration, $banFile, $logFile) {
+    public function __construct($trustedProxies, $nbAttempts, $banDuration, $banFile, LoggerInterface $logger)
+    {
        $this->trustedProxies = $trustedProxies;
        $this->nbAttempts = $nbAttempts;
        $this->banDuration = $banDuration;
        $this->banFile = $banFile;
-        $this->logFile = $logFile;
+        $this->logger = $logger;
        $this->readBanFile();
    }
@@ -78,11 +80,7 @@ class BanManager
        if ($this->failures[$ip] >= $this->nbAttempts) {
            $this->bans[$ip] = time() + $this->banDuration;
-            logm(
+            $this->logger->info(format_log('IP address banned from login: ' . $ip, $ip));
-                $this->logFile,
-                $server['REMOTE_ADDR'],
-                'IP address banned from login: '. $ip
-            );
        }
        $this->writeBanFile();
    }
@@ -138,7 +136,7 @@ class BanManager
            unset($this->failures[$ip]);
        }
        unset($this->bans[$ip]);
-        logm($this->logFile, $server['REMOTE_ADDR'], 'Ban lifted for: '. $ip);
+        $this->logger->info(format_log('Ban lifted for: ' . $ip, $ip));
        $this->writeBanFile();
        return false;
diff --git a/application/security/LoginManager.php b/application/security/LoginManager.php
index 65048f10..b795b80e 100644
--- a/application/security/LoginManager.php
+++ b/application/security/LoginManager.php
@@ -1,7 +1,9 @@
 <?php
 namespace Shaarli\Security;
 use Exception;
+use Psr\Log\LoggerInterface;
 use Shaarli\Config\ConfigManager;
 /**
@@ -31,26 +33,30 @@ class LoginManager
    protected $staySignedInToken = '';
    /** @var CookieManager */
    protected $cookieManager;
+    /** @var LoggerInterface */
+    protected $logger;
    /**
     * Constructor
     *
-     * @param ConfigManager  $configManager  Configuration Manager instance
+     * @param ConfigManager $configManager Configuration Manager instance
     * @param SessionManager $sessionManager SessionManager instance
-     * @param CookieManager  $cookieManager  CookieManager instance
+     * @param CookieManager $cookieManager CookieManager instance
+     * @param BanManager $banManager
+     * @param LoggerInterface $logger Used to log login attempts
     */
-    public function __construct($configManager, $sessionManager, $cookieManager)
+    public function __construct(
-    {
+        ConfigManager $configManager,
+        SessionManager $sessionManager,
+        CookieManager $cookieManager,
+        BanManager $banManager,
+        LoggerInterface $logger
+    ) {
        $this->configManager = $configManager;
        $this->sessionManager = $sessionManager;
        $this->cookieManager = $cookieManager;
-        $this->banManager = new BanManager(
+        $this->banManager = $banManager;
-            $this->configManager->get('security.trusted_proxies', []),
+        $this->logger = $logger;
-            $this->configManager->get('security.ban_after'),
-            $this->configManager->get('security.ban_duration'),
-            $this->configManager->get('resource.ban_file', 'data/ipbans.php'),
-            $this->configManager->get('resource.log')
-        );
        if ($this->configManager->get('security.open_shaarli') === true) {
            $this->openShaarli = true;
@@ -101,7 +107,8 @@ class LoginManager
            // The user client has a valid stay-signed-in cookie
            // Session information is updated with the current client information
            $this->sessionManager->storeLoginInfo($clientIpId);
-        } elseif ($this->sessionManager->hasSessionExpired()
+        } elseif (
+            $this->sessionManager->hasSessionExpired()
            || $this->sessionManager->hasClientIpChanged($clientIpId)
        ) {
            $this->sessionManager->logout();
@@ -129,48 +136,35 @@ class LoginManager
    /**
     * Check user credentials are valid
     *
-     * @param string $remoteIp   Remote client IP address
     * @param string $clientIpId Client IP address identifier
     * @param string $login      Username
     * @param string $password   Password
     *
     * @return bool true if the provided credentials are valid, false otherwise
     */
-    public function checkCredentials($remoteIp, $clientIpId, $login, $password)
+    public function checkCredentials($clientIpId, $login, $password)
    {
-        // Check login matches config
-        if ($login !== $this->configManager->get('credentials.login')) {
-            return false;
-        }
        // Check credentials
        try {
            $useLdapLogin = !empty($this->configManager->get('ldap.host'));
-            if ((false === $useLdapLogin && $this->checkCredentialsFromLocalConfig($login, $password))
+            if (
-                || (true === $useLdapLogin && $this->checkCredentialsFromLdap($login, $password))
+                $login === $this->configManager->get('credentials.login')
+                && (
+                    (false === $useLdapLogin && $this->checkCredentialsFromLocalConfig($login, $password))
+                    || (true === $useLdapLogin && $this->checkCredentialsFromLdap($login, $password))
+                )
            ) {
-                    $this->sessionManager->storeLoginInfo($clientIpId);
+                $this->sessionManager->storeLoginInfo($clientIpId);
-                    logm(
+                $this->logger->info(format_log('Login successful', $clientIpId));
-                        $this->configManager->get('resource.log'),
-                        $remoteIp,
+                return true;
-                        'Login successful'
-                    );
-                    return true;
            }
-        }
+        } catch (Exception $exception) {
-        catch(Exception $exception) {
+            $this->logger->info(format_log('Exception while checking credentials: ' . $exception, $clientIpId));
-            logm(
-                $this->configManager->get('resource.log'),
-                $remoteIp,
-                'Exception while checking credentials: ' . $exception
-            );
        }
-        logm(
+        $this->logger->info(format_log('Login failed for user ' . $login, $clientIpId));
-            $this->configManager->get('resource.log'),
-            $remoteIp,
-            'Login failed for user ' . $login
-        );
        return false;
    }
@@ -183,7 +177,8 @@ class LoginManager
     *
     * @return bool true if the provided credentials are valid, false otherwise
     */
-    public function checkCredentialsFromLocalConfig($login, $password) {
+    public function checkCredentialsFromLocalConfig($login, $password)
+    {
        $hash = sha1($password . $login . $this->configManager->get('credentials.salt'));
        return $login == $this->configManager->get('credentials.login')
@@ -202,14 +197,14 @@ class LoginManager
     */
    public function checkCredentialsFromLdap($login, $password, $connect = null, $bind = null)
    {
-        $connect = $connect ?? function($host) {
+        $connect = $connect ?? function ($host) {
            $resource = ldap_connect($host);
            ldap_set_option($resource, LDAP_OPT_PROTOCOL_VERSION, 3);
            return $resource;
        };
-        $bind = $bind ?? function($handle, $dn, $password) {
+        $bind = $bind ?? function ($handle, $dn, $password) {
            return ldap_bind($handle, $dn, $password);
        };
diff --git a/application/security/SessionManager.php b/application/security/SessionManager.php
index 36df8c1c..f957b91a 100644
--- a/application/security/SessionManager.php
+++ b/application/security/SessionManager.php
@@ -1,4 +1,5 @@
 <?php
 namespace Shaarli\Security;
 use Shaarli\Config\ConfigManager;
@@ -79,7 +80,7 @@ class SessionManager
     */
    public function generateToken()
    {
-        $token = sha1(uniqid('', true) .'_'. mt_rand() . $this->conf->get('credentials.salt'));
+        $token = sha1(uniqid('', true) . '_' . mt_rand() . $this->conf->get('credentials.salt'));
        $this->session['tokens'][$token] = 1;
        return $token;
    }
@@ -293,9 +294,12 @@ class SessionManager
        return session_start();
    }
-    public function cookieParameters(int $lifeTime, string $path, string $domain): bool
+    /**
+     * Be careful, return type of session_set_cookie_params() changed between PHP 7.1 and 7.2.
+     */
+    public function cookieParameters(int $lifeTime, string $path, string $domain): void
    {
-        return session_set_cookie_params($lifeTime, $path, $domain);
+        session_set_cookie_params($lifeTime, $path, $domain);
    }
    public function regenerateId(bool $deleteOldSession = false): bool
diff --git a/application/updater/Updater.php b/application/updater/Updater.php
index 88a7bc7b..4f557d0f 100644
--- a/application/updater/Updater.php
+++ b/application/updater/Updater.php
@@ -88,7 +88,8 @@ class Updater
        foreach ($this->methods as $method) {
            // Not an update method or already done, pass.
-            if (! startsWith($method->getName(), 'updateMethod')
+            if (
+                ! startsWith($method->getName(), 'updateMethod')
                || in_array($method->getName(), $this->doneUpdates)
            ) {
                continue;
@@ -121,12 +122,12 @@ class Updater
    public function readUpdates(string $updatesFilepath): array
    {
-        return UpdaterUtils::read_updates_file($updatesFilepath);
+        return UpdaterUtils::readUpdatesFile($updatesFilepath);
    }
    public function writeUpdates(string $updatesFilepath, array $updates): void
    {
-        UpdaterUtils::write_updates_file($updatesFilepath, $updates);
+        UpdaterUtils::writeUpdatesFile($updatesFilepath, $updates);
    }
    /**
@@ -152,7 +153,8 @@ class Updater
        $updated = false;
        foreach ($this->bookmarkService->search() as $bookmark) {
-            if ($bookmark->isNote()
+            if (
+                $bookmark->isNote()
                && startsWith($bookmark->getUrl(), '?')
                && 1 === preg_match('/^\?([a-zA-Z0-9-_@]{6})($|&|#)/', $bookmark->getUrl(), $match)
            ) {
diff --git a/application/updater/UpdaterUtils.php b/application/updater/UpdaterUtils.php
index 828a49fc..206f826e 100644
--- a/application/updater/UpdaterUtils.php
+++ b/application/updater/UpdaterUtils.php
@@ -11,7 +11,7 @@ class UpdaterUtils
     *
     * @return array Already done update methods.
     */
-    public static function read_updates_file($updatesFilepath)
+    public static function readUpdatesFile($updatesFilepath)
    {
        if (! empty($updatesFilepath) && is_file($updatesFilepath)) {
            $content = file_get_contents($updatesFilepath);
@@ -19,7 +19,7 @@ class UpdaterUtils
                return explode(';', $content);
            }
        }
-        return array();
+        return [];
    }
    /**
@@ -30,7 +30,7 @@ class UpdaterUtils
     *
     * @throws \Exception Couldn't write version number.
     */
-    public static function write_updates_file($updatesFilepath, $updates)
+    public static function writeUpdatesFile($updatesFilepath, $updates)
    {
        if (empty($updatesFilepath)) {
            throw new \Exception('Updates file path is not set, can\'t write updates.');
@@ -38,7 +38,7 @@ class UpdaterUtils
        $res = file_put_contents($updatesFilepath, implode(';', $updates));
        if ($res === false) {
-            throw new \Exception('Unable to write updates in '. $updatesFilepath . '.');
+            throw new \Exception('Unable to write updates in ' . $updatesFilepath . '.');
        }
    }
 }