23 files changed, 1126 insertions, 19 deletions

diff --git a/.htaccess b/.htaccess
new file mode 100644
index 00000000..66ef8f69
--- /dev/null
+++ b/.htaccess
@@ -0,0 +1,4 @@
+RewriteEngine On
+RewriteCond %{REQUEST_FILENAME} !-f
+RewriteCond %{REQUEST_FILENAME} !-d
+RewriteRule ^ index.php [QSA,L]
diff --git a/.travis.yml b/.travis.yml
index 6ff1b20f..03071a47 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,8 +8,6 @@ php:
   - 7.0
   - 5.6
   - 5.5
-  - 5.4
-  - 5.3
 install:
   - composer self-update
   - composer install --prefer-dist
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 21d5436c..fe775b3e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,8 +7,12 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [v0.9.0](https://github.com/shaarli/Shaarli/releases/tag/v0.9.0) - UNPUBLISHED
 
+**WARNING**: Shaarli now requires PHP 5.5+. 
+
 ### Added
 
+- REST API: see [Shaarli API documentation](http://shaarli.github.io/api-documentation/)
+
 ### Changed
 
 ### Fixed
diff --git a/application/Updater.php b/application/Updater.php
index f0d02814..38de3350 100644
--- a/application/Updater.php
+++ b/application/Updater.php
@@ -256,6 +256,29 @@ class Updater
 
         return true;
     }
+
+    /**
+     * Initialize API settings:
+     *   - api.enabled: true
+     *   - api.secret: generated secret
+     */
+    public function updateMethodApiSettings()
+    {
+        if ($this->conf->exists('api.secret')) {
+            return true;
+        }
+
+        $this->conf->set('api.enabled', true);
+        $this->conf->set(
+            'api.secret',
+            generate_api_secret(
+                $this->conf->get('credentials.login'),
+                $this->conf->get('credentials.salt')
+            )
+        );
+        $this->conf->write($this->isLoggedIn);
+        return true;
+    }
 }
 
 /**
diff --git a/application/Utils.php b/application/Utils.php
index 0a5b476e..62902341 100644
--- a/application/Utils.php
+++ b/application/Utils.php
@@ -231,3 +231,29 @@ function autoLocale($headerLocale)
     }
     setlocale(LC_ALL, $attempts);
 }
+
+/**
+ * Generates a default API secret.
+ *
+ * Note that the random-ish methods used in this function are predictable,
+ * which makes them NOT suitable for crypto.
+ * BUT the random string is salted with the salt and hashed with the username.
+ * It makes the generated API secret secured enough for Shaarli.
+ *
+ * PHP 7 provides random_int(), designed for cryptography.
+ * More info: http://stackoverflow.com/questions/4356289/php-random-string-generator
+
+ * @param string $username Shaarli login username
+ * @param string $salt     Shaarli password hash salt
+ *
+ * @return string|bool Generated API secret, 12 char length.
+ *                     Or false if invalid parameters are provided (which will make the API unusable).
+ */
+function generate_api_secret($username, $salt)
+{
+    if (empty($username) || empty($salt)) {
+        return false;
+    }
+
+    return str_shuffle(substr(hash_hmac('sha512', uniqid($salt), $username), 10, 12));
+}
diff --git a/application/api/ApiMiddleware.php b/application/api/ApiMiddleware.php
new file mode 100644
index 00000000..162e88e0
--- /dev/null
+++ b/application/api/ApiMiddleware.php
@@ -0,0 +1,132 @@
+<?php
+
+namespace Shaarli\Api;
+
+use Shaarli\Api\Exceptions\ApiException;
+use Shaarli\Api\Exceptions\ApiAuthorizationException;
+use Slim\Container;
+use Slim\Http\Request;
+use Slim\Http\Response;
+
+/**
+ * Class ApiMiddleware
+ *
+ * This will be called before accessing any API Controller.
+ * Its role is to make sure that the API is enabled, configured, and to validate the JWT token.
+ *
+ * If the request is validated, the controller is called, otherwise a JSON error response is returned.
+ *
+ * @package Api
+ */
+class ApiMiddleware
+{
+    /**
+     * @var int JWT token validity in seconds (9 min).
+     */
+    public static $TOKEN_DURATION = 540;
+
+    /**
+     * @var Container: contains conf, plugins, etc.
+     */
+    protected $container;
+
+    /**
+     * @var \ConfigManager instance.
+     */
+    protected $conf;
+
+    /**
+     * ApiMiddleware constructor.
+     *
+     * @param Container $container instance.
+     */
+    public function __construct($container)
+    {
+        $this->container = $container;
+        $this->conf = $this->container->get('conf');
+        $this->setLinkDb($this->conf);
+    }
+
+    /**
+     * Middleware execution:
+     *   - check the API request
+     *   - execute the controller
+     *   - return the response
+     *
+     * @param  Request  $request  Slim request
+     * @param  Response $response Slim response
+     * @param  callable $next     Next action
+     *
+     * @return Response response.
+     */
+    public function __invoke($request, $response, $next)
+    {
+        try {
+            $this->checkRequest($request);
+            $response = $next($request, $response);
+        } catch(ApiException $e) {
+            $e->setResponse($response);
+            $e->setDebug($this->conf->get('dev.debug', false));
+            $response = $e->getApiResponse();
+        }
+
+        return $response;
+    }
+
+    /**
+     * Check the request validity (HTTP method, request value, etc.),
+     * that the API is enabled, and the JWT token validity.
+     *
+     * @param  Request $request  Slim request
+     *
+     * @throws ApiAuthorizationException The API is disabled or the token is invalid.
+     */
+    protected function checkRequest($request)
+    {
+        if (! $this->conf->get('api.enabled', true)) {
+            throw new ApiAuthorizationException('API is disabled');
+        }
+        $this->checkToken($request);
+    }
+
+    /**
+     * Check that the JWT token is set and valid.
+     * The API secret setting must be set.
+     *
+     * @param  Request $request  Slim request
+     *
+     * @throws ApiAuthorizationException The token couldn't be validated.
+     */
+    protected function checkToken($request) {
+        $jwt = $request->getHeaderLine('jwt');
+        if (empty($jwt)) {
+            throw new ApiAuthorizationException('JWT token not provided');
+        }
+
+        if (empty($this->conf->get('api.secret'))) {
+            throw new ApiAuthorizationException('Token secret must be set in Shaarli\'s administration');
+        }
+
+        ApiUtils::validateJwtToken($jwt, $this->conf->get('api.secret'));
+    }
+
+    /**
+     * Instantiate a new LinkDB including private links,
+     * and load in the Slim container.
+     *
+     * FIXME! LinkDB could use a refactoring to avoid this trick.
+     *
+     * @param \ConfigManager $conf instance.
+     */
+    protected function setLinkDb($conf)
+    {
+        $linkDb = new \LinkDB(
+            $conf->get('resource.datastore'),
+            true,
+            $conf->get('privacy.hide_public_links'),
+            $conf->get('redirector.url'),
+            $conf->get('redirector.encode_url')
+        );
+        $this->container['db'] = $linkDb;
+    }
+}
diff --git a/application/api/ApiUtils.php b/application/api/ApiUtils.php
new file mode 100644
index 00000000..fbb1e72f
--- /dev/null
+++ b/application/api/ApiUtils.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace Shaarli\Api;
+
+use Shaarli\Api\Exceptions\ApiAuthorizationException;
+
+/**
+ * Class ApiUtils
+ *
+ * Utility functions for the API.
+ */
+class ApiUtils
+{
+    /**
+     * Validates a JWT token authenticity.
+     *
+     * @param string $token  JWT token extracted from the headers.
+     * @param string $secret API secret set in the settings.
+     *
+     * @throws ApiAuthorizationException the token is not valid.
+     */
+    public static function validateJwtToken($token, $secret)
+    {
+        $parts = explode('.', $token);
+        if (count($parts) != 3 || strlen($parts[0]) == 0 || strlen($parts[1]) == 0) {
+            throw new ApiAuthorizationException('Malformed JWT token');
+        }
+
+        $genSign = hash_hmac('sha512', $parts[0] .'.'. $parts[1], $secret);
+        if ($parts[2] != $genSign) {
+            throw new ApiAuthorizationException('Invalid JWT signature');
+        }
+
+        $header = json_decode(base64_decode($parts[0]));
+        if ($header === null) {
+            throw new ApiAuthorizationException('Invalid JWT header');
+        }
+
+        $payload = json_decode(base64_decode($parts[1]));
+        if ($payload === null) {
+            throw new ApiAuthorizationException('Invalid JWT payload');
+        }
+
+        if (empty($payload->iat)
+            || $payload->iat > time()
+            || time() - $payload->iat > ApiMiddleware::$TOKEN_DURATION
+        ) {
+            throw new ApiAuthorizationException('Invalid JWT issued time');
+        }
+    }
+}
diff --git a/application/api/controllers/ApiController.php b/application/api/controllers/ApiController.php
new file mode 100644
index 00000000..1dd47f17
--- /dev/null
+++ b/application/api/controllers/ApiController.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace Shaarli\Api\Controllers;
+
+use \Slim\Container;
+
+/**
+ * Abstract Class ApiController
+ *
+ * Defines REST API Controller dependencies injected from the container.
+ *
+ * @package Api\Controllers
+ */
+abstract class ApiController
+{
+    /**
+     * @var Container
+     */
+    protected $ci;
+
+    /**
+     * @var \ConfigManager
+     */
+    protected $conf;
+
+    /**
+     * @var \LinkDB
+     */
+    protected $linkDb;
+
+    /**
+     * @var int|null JSON style option.
+     */
+    protected $jsonStyle;
+
+    /**
+     * ApiController constructor.
+     * 
+     * Note: enabling debug mode displays JSON with readable formatting.
+     *
+     * @param Container $ci Slim container.
+     */
+    public function __construct(Container $ci)
+    {
+        $this->ci = $ci;
+        $this->conf = $ci->get('conf');
+        $this->linkDb = $ci->get('db');
+        if ($this->conf->get('dev.debug', false)) {
+            $this->jsonStyle = JSON_PRETTY_PRINT;
+        } else {
+            $this->jsonStyle = null;
+        }
+    }
+}
diff --git a/application/api/controllers/Info.php b/application/api/controllers/Info.php
new file mode 100644
index 00000000..25433f72
--- /dev/null
+++ b/application/api/controllers/Info.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace Shaarli\Api\Controllers;
+
+use Slim\Http\Request;
+use Slim\Http\Response;
+
+/**
+ * Class Info
+ * 
+ * REST API Controller: /info
+ *
+ * @package Api\Controllers
+ * @see http://shaarli.github.io/api-documentation/#links-instance-information-get
+ */
+class Info extends ApiController
+{
+    /**
+     * Service providing various information about Shaarli instance.
+     * 
+     * @param Request  $request  Slim request.
+     * @param Response $response Slim response.
+     *
+     * @return Response response.
+     */
+    public function getInfo($request, $response)
+    {
+        $info = [
+            'global_counter' => count($this->linkDb),
+            'private_counter' => count_private($this->linkDb),
+            'settings' => array(
+                '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/exceptions/ApiAuthorizationException.php b/application/api/exceptions/ApiAuthorizationException.php
new file mode 100644
index 00000000..0e3f4776
--- /dev/null
+++ b/application/api/exceptions/ApiAuthorizationException.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Shaarli\Api\Exceptions;
+
+/**
+ * Class ApiAuthorizationException
+ *
+ * Request not authorized, return a 401 HTTP code.
+ */
+class ApiAuthorizationException extends ApiException
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getApiResponse()
+    {
+        $this->setMessage('Not authorized');
+        return $this->buildApiResponse(401);
+    }
+
+    /**
+     * Set the exception message.
+     *
+     * We only return a generic error message in production mode to avoid giving
+     * to much security information.
+     *
+     * @param $message string the exception message.
+     */
+    public function setMessage($message)
+    {
+        $original = $this->debug === true ? ': '. $this->getMessage() : '';
+        $this->message = $message . $original;
+    }
+}
diff --git a/application/api/exceptions/ApiBadParametersException.php b/application/api/exceptions/ApiBadParametersException.php
new file mode 100644
index 00000000..e5cc19ea
--- /dev/null
+++ b/application/api/exceptions/ApiBadParametersException.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Shaarli\Api\Exceptions;
+
+/**
+ * Class ApiBadParametersException
+ *
+ * Invalid request exception, return a 400 HTTP code.
+ */
+class ApiBadParametersException extends ApiException
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getApiResponse()
+    {
+        return $this->buildApiResponse(400);
+    }
+}
diff --git a/application/api/exceptions/ApiException.php b/application/api/exceptions/ApiException.php
new file mode 100644
index 00000000..c8490e0c
--- /dev/null
+++ b/application/api/exceptions/ApiException.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace Shaarli\Api\Exceptions;
+
+use Slim\Http\Response;
+
+/**
+ * Abstract class ApiException
+ *
+ * Parent Exception related to the API, able to generate a valid Response (ResponseInterface).
+ * Also can include various information in debug mode.
+ */
+abstract class ApiException extends \Exception {
+
+    /**
+     * @var Response instance from Slim.
+     */
+    protected $response;
+
+    /**
+     * @var bool Debug mode enabled/disabled.
+     */
+    protected $debug;
+
+    /**
+     * Build the final response.
+     *
+     * @return Response Final response to give.
+     */
+    public abstract function getApiResponse();
+
+    /**
+     * Creates ApiResponse body.
+     * In production mode, it will only return the exception message,
+     * but in dev mode, it includes additional information in an array.
+     *
+     * @return array|string response body
+     */
+    protected function getApiResponseBody() {
+        if ($this->debug !== true) {
+            return $this->getMessage();
+        }
+        return [
+            'message' => $this->getMessage(),
+            'stacktrace' => get_class($this) .': '. $this->getTraceAsString()
+        ];
+    }
+
+    /**
+     * Build the Response object to return.
+     *
+     * @param int $code HTTP status.
+     *
+     * @return Response with status + body.
+     */
+    protected function buildApiResponse($code)
+    {
+        $style = $this->debug ? JSON_PRETTY_PRINT : null;
+        return $this->response->withJson($this->getApiResponseBody(), $code, $style);
+    }
+
+    /**
+     * @param Response $response
+     */
+    public function setResponse($response)
+    {
+        $this->response = $response;
+    }
+
+    /**
+     * @param bool $debug
+     */
+    public function setDebug($debug)
+    {
+        $this->debug = $debug;
+    }
+}
diff --git a/application/api/exceptions/ApiInternalException.php b/application/api/exceptions/ApiInternalException.php
new file mode 100644
index 00000000..1cb05532
--- /dev/null
+++ b/application/api/exceptions/ApiInternalException.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Shaarli\Api\Exceptions;
+
+/**
+ * Class ApiInternalException
+ *
+ * Generic exception, return a 500 HTTP code.
+ */
+class ApiInternalException extends ApiException
+{
+    /**
+     * @inheritdoc
+     */
+    public function getApiResponse()
+    {
+        return $this->buildApiResponse(500);
+    }
+}
diff --git a/application/config/ConfigManager.php b/application/config/ConfigManager.php
index f5f753f8..ca8918b5 100644
--- a/application/config/ConfigManager.php
+++ b/application/config/ConfigManager.php
@@ -20,6 +20,8 @@ class ConfigManager
      */
     protected static $NOT_FOUND = 'NOT_FOUND';
 
+    public static $DEFAULT_PLUGINS = array('qrcode');
+
     /**
      * @var string Config folder.
      */
@@ -308,7 +310,7 @@ class ConfigManager
 
         $this->setEmpty('general.header_link', '?');
         $this->setEmpty('general.links_per_page', 20);
-        $this->setEmpty('general.enabled_plugins', array('qrcode'));
+        $this->setEmpty('general.enabled_plugins', self::$DEFAULT_PLUGINS);
 
         $this->setEmpty('updates.check_updates', false);
         $this->setEmpty('updates.check_updates_branch', 'stable');
diff --git a/composer.json b/composer.json
index f7d26a31..4786fe94 100644
--- a/composer.json
+++ b/composer.json
@@ -10,14 +10,22 @@
     },
     "keywords": ["bookmark", "link", "share", "web"],
     "require": {
-        "php": ">=5.3.4",
+        "php": ">=5.5",
         "shaarli/netscape-bookmark-parser": "1.*",
-        "erusev/parsedown": "1.6"
+        "erusev/parsedown": "1.6",
+        "slim/slim": "^3.0"
     },
     "require-dev": {
         "phpmd/phpmd" : "@stable",
         "phpunit/phpunit": "4.8.*",
         "sebastian/phpcpd": "*",
         "squizlabs/php_codesniffer": "2.*"
+    },
+    "autoload": {
+        "psr-4": {
+            "Shaarli\\Api\\": "application/api/",
+            "Shaarli\\Api\\Controllers\\": "application/api/controllers",
+            "Shaarli\\Api\\Exceptions\\": "application/api/exceptions"
+        }
     }
 }
diff --git a/index.php b/index.php
index a0a3a8c7..eb73941d 100644
--- a/index.php
+++ b/index.php
@@ -175,7 +175,6 @@ define('STAY_SIGNED_IN_TOKEN', sha1($conf->get('credentials.hash') . $_SERVER['R
 if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
     autoLocale($_SERVER['HTTP_ACCEPT_LANGUAGE']);
 }
-header('Content-Type: text/html; charset=utf-8'); // We use UTF-8 for proper international characters handling.
 
 /**
  * Checking session state (i.e. is the user still logged in)
@@ -731,17 +730,10 @@ function showLinkList($PAGE, $LINKSDB, $conf, $pluginManager) {
  *
  * @param ConfigManager $conf          Configuration Manager instance.
  * @param PluginManager $pluginManager Plugin Manager instance,
+ * @param LinkDB        $LINKSDB
  */
-function renderPage($conf, $pluginManager)
+function renderPage($conf, $pluginManager, $LINKSDB)
 {
-    $LINKSDB = new LinkDB(
-        $conf->get('resource.datastore'),
-        isLoggedIn(),
-        $conf->get('privacy.hide_public_links'),
-        $conf->get('redirector.url'),
-        $conf->get('redirector.encode_url')
-    );
-
     $updater = new Updater(
         read_updates_file($conf->get('resource.updates')),
         $LINKSDB,
@@ -938,7 +930,7 @@ function renderPage($conf, $pluginManager)
         exit;
     }
 
-    // Display openseach plugin (XML)
+    // Display opensearch plugin (XML)
     if ($targetPage == Router::$PAGE_OPENSEARCH) {
         header('Content-Type: application/xml; charset=utf-8');
         $PAGE->assign('serverurl', index_url($_SERVER));
@@ -1142,6 +1134,8 @@ function renderPage($conf, $pluginManager)
             $conf->set('feed.rss_permalinks', !empty($_POST['enableRssPermalinks']));
             $conf->set('updates.check_updates', !empty($_POST['updateCheck']));
             $conf->set('privacy.hide_public_links', !empty($_POST['hidePublicLinks']));
+            $conf->set('api.enabled', !empty($_POST['apiEnabled']));
+            $conf->set('api.secret', escape($_POST['apiSecret']));
             try {
                 $conf->write(isLoggedIn());
             }
@@ -1170,6 +1164,8 @@ function renderPage($conf, $pluginManager)
             $PAGE->assign('enable_rss_permalinks', $conf->get('feed.rss_permalinks', false));
             $PAGE->assign('enable_update_check', $conf->get('updates.check_updates', true));
             $PAGE->assign('hide_public_links', $conf->get('privacy.hide_public_links', false));
+            $PAGE->assign('api_enabled', $conf->get('api.enabled', true));
+            $PAGE->assign('api_secret', $conf->get('api.secret'));
             $PAGE->renderPage('configure');
             exit;
         }
@@ -1954,6 +1950,14 @@ function install($conf)
             $conf->set('general.title', 'Shared links on '.escape(index_url($_SERVER)));
         }
         $conf->set('updates.check_updates', !empty($_POST['updateCheck']));
+        $conf->set('api.enabled', !empty($_POST['enableApi']));
+        $conf->set(
+            'api.secret',
+            generate_api_secret(
+                $this->conf->get('credentials.login'),
+                $this->conf->get('credentials.salt')
+            )
+        );
         try {
             // Everything is ok, let's create config file.
             $conf->write(isLoggedIn());
@@ -2216,4 +2220,32 @@ if (isset($_SERVER['QUERY_STRING']) && startsWith($_SERVER['QUERY_STRING'], 'do=
 if (!isset($_SESSION['LINKS_PER_PAGE'])) {
     $_SESSION['LINKS_PER_PAGE'] = $conf->get('general.links_per_page', 20);
 }
-renderPage($conf, $pluginManager);
+
+$linkDb = new LinkDB(
+    $conf->get('resource.datastore'),
+    isLoggedIn(),
+    $conf->get('privacy.hide_public_links'),
+    $conf->get('redirector.url'),
+    $conf->get('redirector.encode_url')
+);
+
+$container = new \Slim\Container();
+$container['conf'] = $conf;
+$container['plugins'] = $pluginManager;
+$app = new \Slim\App($container);
+
+// REST API routes
+$app->group('/api/v1', function() {
+    $this->get('/info', '\Api\Controllers\Info:getInfo');
+})->add('\Api\ApiMiddleware');
+
+$response = $app->run(true);
+// Hack to make Slim and Shaarli router work together:
+// If a Slim route isn't found, we call renderPage().
+if ($response->getStatusCode() == 404) {
+    // We use UTF-8 for proper international characters handling.
+    header('Content-Type: text/html; charset=utf-8');
+    renderPage($conf, $pluginManager, $linkDb);
+} else {
+    $app->respond($response);
+}
diff --git a/tests/Updater/UpdaterTest.php b/tests/Updater/UpdaterTest.php
index 4948fe52..0171daad 100644
--- a/tests/Updater/UpdaterTest.php
+++ b/tests/Updater/UpdaterTest.php
@@ -271,7 +271,7 @@ $GLOBALS[\'privateLinkByDefault\'] = true;';
     public function testEscapeConfig()
     {
         $sandbox = 'sandbox/config';
-        copy(self::$configFile .'.json.php', $sandbox .'.json.php');
+        copy(self::$configFile . '.json.php', $sandbox . '.json.php');
         $this->conf = new ConfigManager($sandbox);
         $title = '<script>alert("title");</script>';
         $headerLink = '<script>alert("header_link");</script>';
@@ -286,7 +286,43 @@ $GLOBALS[\'privateLinkByDefault\'] = true;';
         $this->assertEquals(escape($title), $this->conf->get('general.title'));
         $this->assertEquals(escape($headerLink), $this->conf->get('general.header_link'));
         $this->assertEquals(escape($redirectorUrl), $this->conf->get('redirector.url'));
-        unlink($sandbox .'.json.php');
+        unlink($sandbox . '.json.php');
+    }
+
+    /**
+     * Test updateMethodApiSettings(): create default settings for the API (enabled + secret).
+     */
+    public function testUpdateApiSettings()
+    {
+        $confFile = 'sandbox/config';
+        copy(self::$configFile .'.json.php', $confFile .'.json.php');
+        $conf = new ConfigManager($confFile);
+        $updater = new Updater(array(), array(), $conf, true);
+
+        $this->assertFalse($conf->exists('api.enabled'));
+        $this->assertFalse($conf->exists('api.secret'));
+        $updater->updateMethodApiSettings();
+        $conf->reload();
+        $this->assertTrue($conf->get('api.enabled'));
+        $this->assertTrue($conf->exists('api.secret'));
+        unlink($confFile .'.json.php');
+    }
+
+    /**
+     * Test updateMethodApiSettings(): already set, do nothing.
+     */
+    public function testUpdateApiSettingsNothingToDo()
+    {
+        $confFile = 'sandbox/config';
+        copy(self::$configFile .'.json.php', $confFile .'.json.php');
+        $conf = new ConfigManager($confFile);
+        $conf->set('api.enabled', false);
+        $conf->set('api.secret', '');
+        $updater = new Updater(array(), array(), $conf, true);
+        $updater->updateMethodApiSettings();
+        $this->assertFalse($conf->get('api.enabled'));
+        $this->assertEmpty($conf->get('api.secret'));
+        unlink($confFile .'.json.php');
     }
 
     /**
diff --git a/tests/UtilsTest.php b/tests/UtilsTest.php
index 6a7870c4..0cf9a921 100644
--- a/tests/UtilsTest.php
+++ b/tests/UtilsTest.php
@@ -253,4 +253,21 @@ class UtilsTest extends PHPUnit_Framework_TestCase
             is_session_id_valid('c0ZqcWF3VFE2NmJBdm1HMVQ0ZHJ3UmZPbTFsNGhkNHI=')
         );
     }
+
+    /**
+     * Test generateSecretApi.
+     */
+    public function testGenerateSecretApi()
+    {
+        $this->assertEquals(12, strlen(generate_api_secret('foo', 'bar')));
+    }
+
+    /**
+     * Test generateSecretApi with invalid parameters.
+     */
+    public function testGenerateSecretApiInvalid()
+    {
+        $this->assertFalse(generate_api_secret('', ''));
+        $this->assertFalse(generate_api_secret(false, false));
+    }
 }
diff --git a/tests/api/ApiMiddlewareTest.php b/tests/api/ApiMiddlewareTest.php
new file mode 100644
index 00000000..4d4dd9b9
--- /dev/null
+++ b/tests/api/ApiMiddlewareTest.php
@@ -0,0 +1,184 @@
+<?php
+
+namespace Shaarli\Api;
+
+use Slim\Container;
+use Slim\Http\Environment;
+use Slim\Http\Request;
+use Slim\Http\Response;
+
+/**
+ * Class ApiMiddlewareTest
+ *
+ * Test the REST API Slim Middleware.
+ *
+ * Note that we can't test a valid use case here, because the middleware
+ * needs to call a valid controller/action during its execution.
+ *
+ * @package Api
+ */
+class ApiMiddlewareTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var string datastore to test write operations
+     */
+    protected static $testDatastore = 'sandbox/datastore.php';
+
+    /**
+     * @var \ConfigManager instance
+     */
+    protected $conf;
+
+    /**
+     * @var \ReferenceLinkDB instance.
+     */
+    protected $refDB = null;
+
+    /**
+     * @var Container instance.
+     */
+    protected $container;
+
+    /**
+     * Before every test, instantiate a new Api with its config, plugins and links.
+     */
+    public function setUp()
+    {
+        $this->conf = new \ConfigManager('tests/utils/config/configJson.json.php');
+        $this->conf->set('api.secret', 'NapoleonWasALizard');
+
+        $this->refDB = new \ReferenceLinkDB();
+        $this->refDB->write(self::$testDatastore);
+
+        $this->container = new Container();
+        $this->container['conf'] = $this->conf;
+    }
+
+    /**
+     * After every test, remove the test datastore.
+     */
+    public function tearDown()
+    {
+        @unlink(self::$testDatastore);
+    }
+
+    /**
+     * Invoke the middleware with the API disabled:
+     * should return a 401 error Unauthorized.
+     */
+    public function testInvokeMiddlewareApiDisabled()
+    {
+        $this->conf->set('api.enabled', false);
+        $mw = new ApiMiddleware($this->container);
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'GET',
+            'REQUEST_URI' => '/echo',
+        ]);
+        $request = Request::createFromEnvironment($env);
+        $response = new Response();
+        /** @var Response $response */
+        $response = $mw($request, $response, null);
+
+        $this->assertEquals(401, $response->getStatusCode());
+        $body = json_decode((string) $response->getBody());
+        $this->assertEquals('Not authorized', $body);
+    }
+
+    /**
+     * Invoke the middleware with the API disabled in debug mode:
+     * should return a 401 error Unauthorized - with a specific message and a stacktrace.
+     */
+    public function testInvokeMiddlewareApiDisabledDebug()
+    {
+        $this->conf->set('api.enabled', false);
+        $this->conf->set('dev.debug', true);
+        $mw = new ApiMiddleware($this->container);
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'GET',
+            'REQUEST_URI' => '/echo',
+        ]);
+        $request = Request::createFromEnvironment($env);
+        $response = new Response();
+        /** @var Response $response */
+        $response = $mw($request, $response, null);
+
+        $this->assertEquals(401, $response->getStatusCode());
+        $body = json_decode((string) $response->getBody());
+        $this->assertEquals('Not authorized: API is disabled', $body->message);
+        $this->assertContains('ApiAuthorizationException', $body->stacktrace);
+    }
+
+    /**
+     * Invoke the middleware without a token (debug):
+     * should return a 401 error Unauthorized - with a specific message and a stacktrace.
+     */
+    public function testInvokeMiddlewareNoTokenProvidedDebug()
+    {
+        $this->conf->set('dev.debug', true);
+        $mw = new ApiMiddleware($this->container);
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'GET',
+            'REQUEST_URI' => '/echo',
+        ]);
+        $request = Request::createFromEnvironment($env);
+        $response = new Response();
+        /** @var Response $response */
+        $response = $mw($request, $response, null);
+
+        $this->assertEquals(401, $response->getStatusCode());
+        $body = json_decode((string) $response->getBody());
+        $this->assertEquals('Not authorized: JWT token not provided', $body->message);
+        $this->assertContains('ApiAuthorizationException', $body->stacktrace);
+    }
+
+    /**
+     * Invoke the middleware without a secret set in settings (debug):
+     * should return a 401 error Unauthorized - with a specific message and a stacktrace.
+     */
+    public function testInvokeMiddlewareNoSecretSetDebug()
+    {
+        $this->conf->set('dev.debug', true);
+        $this->conf->set('api.secret', '');
+        $mw = new ApiMiddleware($this->container);
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'GET',
+            'REQUEST_URI' => '/echo',
+            'HTTP_JWT'=> 'jwt',
+        ]);
+        $request = Request::createFromEnvironment($env);
+        $response = new Response();
+        /** @var Response $response */
+        $response = $mw($request, $response, null);
+
+        $this->assertEquals(401, $response->getStatusCode());
+        $body = json_decode((string) $response->getBody());
+        $this->assertEquals('Not authorized: Token secret must be set in Shaarli\'s administration', $body->message);
+        $this->assertContains('ApiAuthorizationException', $body->stacktrace);
+    }
+
+    /**
+     * Invoke the middleware without an invalid JWT token (debug):
+     * should return a 401 error Unauthorized - with a specific message and a stacktrace.
+     *
+     * Note: specific JWT errors tests are handled in ApiUtilsTest.
+     */
+    public function testInvokeMiddlewareInvalidJwtDebug()
+    {
+        $this->conf->set('dev.debug', true);
+        $mw = new ApiMiddleware($this->container);
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'GET',
+            'REQUEST_URI' => '/echo',
+            'HTTP_JWT'=> 'bad jwt',
+        ]);
+        $request = Request::createFromEnvironment($env);
+        $response = new Response();
+        /** @var Response $response */
+        $response = $mw($request, $response, null);
+
+        $this->assertEquals(401, $response->getStatusCode());
+        $body = json_decode((string) $response->getBody());
+        $this->assertEquals('Not authorized: Malformed JWT token', $body->message);
+        $this->assertContains('ApiAuthorizationException', $body->stacktrace);
+    }
+}
diff --git a/tests/api/ApiUtilsTest.php b/tests/api/ApiUtilsTest.php
new file mode 100644
index 00000000..10da1459
--- /dev/null
+++ b/tests/api/ApiUtilsTest.php
@@ -0,0 +1,206 @@
+<?php
+
+namespace Shaarli\Api;
+
+/**
+ * Class ApiUtilsTest
+ */
+class ApiUtilsTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * Force the timezone for ISO datetimes.
+     */
+    public static function setUpBeforeClass()
+    {
+        date_default_timezone_set('UTC');
+    }
+
+    /**
+     * Generate a valid JWT token.
+     *
+     * @param string $secret API secret used to generate the signature.
+     *
+     * @return string Generated token.
+     */
+    public static function generateValidJwtToken($secret)
+    {
+        $header = base64_encode('{
+            "typ": "JWT",
+            "alg": "HS512"
+        }');
+        $payload = base64_encode('{
+            "iat": '. time() .'
+        }');
+        $signature = hash_hmac('sha512', $header .'.'. $payload , $secret);
+        return $header .'.'. $payload .'.'. $signature;
+    }
+
+    /**
+     * Generate a JWT token from given header and payload.
+     *
+     * @param string $header  Header in JSON format.
+     * @param string $payload Payload in JSON format.
+     * @param string $secret  API secret used to hash the signature.
+     *
+     * @return string JWT token.
+     */
+    public static function generateCustomJwtToken($header, $payload, $secret)
+    {
+        $header = base64_encode($header);
+        $payload = base64_encode($payload);
+        $signature = hash_hmac('sha512', $header . '.' . $payload, $secret);
+        return $header . '.' . $payload . '.' . $signature;
+    }
+
+    /**
+     * Test validateJwtToken() with a valid JWT token.
+     */
+    public function testValidateJwtTokenValid()
+    {
+        $secret = 'WarIsPeace';
+        ApiUtils::validateJwtToken(self::generateValidJwtToken($secret), $secret);
+    }
+
+    /**
+     * Test validateJwtToken() with a malformed JWT token.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Malformed JWT token
+     */
+    public function testValidateJwtTokenMalformed()
+    {
+        $token = 'ABC.DEF';
+        ApiUtils::validateJwtToken($token, 'foo');
+    }
+
+    /**
+     * Test validateJwtToken() with an empty JWT token.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Malformed JWT token
+     */
+    public function testValidateJwtTokenMalformedEmpty()
+    {
+        $token = false;
+        ApiUtils::validateJwtToken($token, 'foo');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token without header.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Malformed JWT token
+     */
+    public function testValidateJwtTokenMalformedEmptyHeader()
+    {
+        $token = '.payload.signature';
+        ApiUtils::validateJwtToken($token, 'foo');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token without payload
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Malformed JWT token
+     */
+    public function testValidateJwtTokenMalformedEmptyPayload()
+    {
+        $token = 'header..signature';
+        ApiUtils::validateJwtToken($token, 'foo');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token with an empty signature.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Invalid JWT signature
+     */
+    public function testValidateJwtTokenInvalidSignatureEmpty()
+    {
+        $token = 'header.payload.';
+        ApiUtils::validateJwtToken($token, 'foo');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token with an invalid signature.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Invalid JWT signature
+     */
+    public function testValidateJwtTokenInvalidSignature()
+    {
+        $token = 'header.payload.nope';
+        ApiUtils::validateJwtToken($token, 'foo');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token with a signature generated with the wrong API secret.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Invalid JWT signature
+     */
+    public function testValidateJwtTokenInvalidSignatureSecret()
+    {
+        ApiUtils::validateJwtToken(self::generateValidJwtToken('foo'), 'bar');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token with a an invalid header (not JSON).
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Invalid JWT header
+     */
+    public function testValidateJwtTokenInvalidHeader()
+    {
+        $token = $this->generateCustomJwtToken('notJSON', '{"JSON":1}', 'secret');
+        ApiUtils::validateJwtToken($token, 'secret');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token with a an invalid payload (not JSON).
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Invalid JWT payload
+     */
+    public function testValidateJwtTokenInvalidPayload()
+    {
+        $token = $this->generateCustomJwtToken('{"JSON":1}', 'notJSON', 'secret');
+        ApiUtils::validateJwtToken($token, 'secret');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token without issued time.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Invalid JWT issued time
+     */
+    public function testValidateJwtTokenInvalidTimeEmpty()
+    {
+        $token = $this->generateCustomJwtToken('{"JSON":1}', '{"JSON":1}', 'secret');
+        ApiUtils::validateJwtToken($token, 'secret');
+    }
+
+    /**
+     * Test validateJwtToken() with an expired JWT token.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Invalid JWT issued time
+     */
+    public function testValidateJwtTokenInvalidTimeExpired()
+    {
+        $token = $this->generateCustomJwtToken('{"JSON":1}', '{"iat":' . (time() - 600) . '}', 'secret');
+        ApiUtils::validateJwtToken($token, 'secret');
+    }
+
+    /**
+     * Test validateJwtToken() with a JWT token issued in the future.
+     *
+     * @expectedException \Shaarli\Api\Exceptions\ApiAuthorizationException
+     * @expectedExceptionMessage Invalid JWT issued time
+     */
+    public function testValidateJwtTokenInvalidTimeFuture()
+    {
+        $token = $this->generateCustomJwtToken('{"JSON":1}', '{"iat":' . (time() + 60) . '}', 'secret');
+        ApiUtils::validateJwtToken($token, 'secret');
+    }
+}
diff --git a/tests/api/controllers/InfoTest.php b/tests/api/controllers/InfoTest.php
new file mode 100644
index 00000000..2916eed8
--- /dev/null
+++ b/tests/api/controllers/InfoTest.php
@@ -0,0 +1,113 @@
+<?php
+
+namespace Shaarli\Api\Controllers;
+
+use Slim\Container;
+use Slim\Http\Environment;
+use Slim\Http\Request;
+use Slim\Http\Response;
+
+/**
+ * Class InfoTest
+ * 
+ * Test REST API controller Info.
+ * 
+ * @package Api\Controllers
+ */
+class InfoTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var string datastore to test write operations
+     */
+    protected static $testDatastore = 'sandbox/datastore.php';
+
+    /**
+     * @var \ConfigManager instance
+     */
+    protected $conf;
+
+    /**
+     * @var \ReferenceLinkDB instance.
+     */
+    protected $refDB = null;
+
+    /**
+     * @var Container instance.
+     */
+    protected $container;
+
+    /**
+     * @var Info controller instance.
+     */
+    protected $controller;
+
+    /**
+     * Before every test, instantiate a new Api with its config, plugins and links.
+     */
+    public function setUp()
+    {
+        $this->conf = new \ConfigManager('tests/utils/config/configJson.json.php');
+        $this->refDB = new \ReferenceLinkDB();
+        $this->refDB->write(self::$testDatastore);
+
+        $this->container = new Container();
+        $this->container['conf'] = $this->conf;
+        $this->container['db'] = new \LinkDB(self::$testDatastore, true, false);
+
+        $this->controller = new Info($this->container);
+    }
+
+    /**
+     * After every test, remove the test datastore.
+     */
+    public function tearDown()
+    {
+        @unlink(self::$testDatastore);
+    }
+
+    /**
+     * Test /info service.
+     */
+    public function testGetInfo()
+    {
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'GET',
+        ]);
+        $request = Request::createFromEnvironment($env);
+
+        $response = $this->controller->getInfo($request, new Response());
+        $this->assertEquals(200, $response->getStatusCode());
+        $data = json_decode((string) $response->getBody(), true);
+
+        $this->assertEquals(8, $data['global_counter']);
+        $this->assertEquals(2, $data['private_counter']);
+        $this->assertEquals('Shaarli', $data['settings']['title']);
+        $this->assertEquals('?', $data['settings']['header_link']);
+        $this->assertEquals('UTC', $data['settings']['timezone']);
+        $this->assertEquals(\ConfigManager::$DEFAULT_PLUGINS, $data['settings']['enabled_plugins']);
+        $this->assertEquals(false, $data['settings']['default_private_links']);
+
+        $title = 'My links';
+        $headerLink = 'http://shaarli.tld';
+        $timezone = 'Europe/Paris';
+        $enabledPlugins = array('foo', 'bar');
+        $defaultPrivateLinks = true;
+        $this->conf->set('general.title', $title);
+        $this->conf->set('general.header_link', $headerLink);
+        $this->conf->set('general.timezone', $timezone);
+        $this->conf->set('general.enabled_plugins', $enabledPlugins);
+        $this->conf->set('privacy.default_private_links', $defaultPrivateLinks);
+
+        $response = $this->controller->getInfo($request, new Response());
+        $this->assertEquals(200, $response->getStatusCode());
+        $data = json_decode((string) $response->getBody(), true);
+
+        $this->assertEquals(8, $data['global_counter']);
+        $this->assertEquals(2, $data['private_counter']);
+        $this->assertEquals($title, $data['settings']['title']);
+        $this->assertEquals($headerLink, $data['settings']['header_link']);
+        $this->assertEquals($timezone, $data['settings']['timezone']);
+        $this->assertEquals($enabledPlugins, $data['settings']['enabled_plugins']);
+        $this->assertEquals($defaultPrivateLinks, $data['settings']['default_private_links']);
+    }
+}
diff --git a/tpl/configure.html b/tpl/configure.html
index 983bcd08..b4197bf9 100644
--- a/tpl/configure.html
+++ b/tpl/configure.html
@@ -80,6 +80,20 @@
           <label for="updateCheck">&nbsp;Notify me when a new release is ready</label>
         </td>
       </tr>
+      <tr>
+        <td valign="top"><b>Enable REST API</b></td>
+        <td>
+          <input type="checkbox" name="apiEnabled" id="apiEnabled"
+                 {if="$api_enabled"}checked{/if}/>
+          <label for="apiEnabled">&nbsp;Allow third party software to use Shaarli such as mobile application.</label>
+        </td>
+      </tr>
+      <tr>
+        <td valign="top"><b>API secret</b></td>
+        <td>
+          <input type="text" name="apiSecret" id="apiSecret" size="50" value="{$api_secret}" />
+        </td>
+      </tr>
 
       <tr>
         <td></td>
diff --git a/tpl/install.html b/tpl/install.html
index 88eb540e..42874dcd 100644
--- a/tpl/install.html
+++ b/tpl/install.html
@@ -14,6 +14,18 @@
             <tr><td valign="top"><b>Update:</b></td><td>
                 <input type="checkbox" name="updateCheck" id="updateCheck" checked="checked"><label for="updateCheck">&nbsp;Notify me when a new release is ready</label></td>
             </tr>
+            <tr>
+                <td valign="top">
+                    <b>API:</b>
+                </td>
+                <td>
+                    <input type="checkbox" name="enableApi" id="enableApi" checked="checked">
+                    <label for="enableApi">
+                        &nbsp;Enable Shaarli's REST API.
+                        Allow third party software to use Shaarli such as mobile application.
+                    </label>
+                </td>
+            </tr>
             <tr><td colspan="2"><input type="submit" name="Save" value="Save config" class="bigbutton"></td></tr>
         </table>
     </form>