6 files changed, 134 insertions, 41 deletions

diff --git a/application/feed/FeedBuilder.php b/application/feed/FeedBuilder.php
index 3653c32f..f6def630 100644
--- a/application/feed/FeedBuilder.php
+++ b/application/feed/FeedBuilder.php
@@ -122,9 +122,9 @@ class FeedBuilder
         $data['language'] = $this->getTypeLanguage($feedType);
         $data['last_update'] = $this->getLatestDateFormatted($feedType);
         $data['show_dates'] = !$this->hideDates || $this->isLoggedIn;
-        // Remove leading slash from REQUEST_URI.
-        $data['self_link'] = escape(server_url($this->serverInfo))
-            . escape($this->serverInfo['REQUEST_URI']);
+        // Remove leading path from REQUEST_URI (already contained in $pageaddr).
+        $requestUri = preg_replace('#(.*?/)(feed.*)#', '$2', escape($this->serverInfo['REQUEST_URI']));
+        $data['self_link'] = $pageaddr . $requestUri;
         $data['index_url'] = $pageaddr;
         $data['usepermalinks'] = $this->usePermalinks === true;
         $data['links'] = $linkDisplayed;
diff --git a/application/http/HttpUtils.php b/application/http/HttpUtils.php
index 4fc4e3dc..9f414073 100644
--- a/application/http/HttpUtils.php
+++ b/application/http/HttpUtils.php
@@ -369,7 +369,11 @@ function server_url($server)
  */
 function index_url($server)
 {
-    $scriptname = $server['SCRIPT_NAME'] ?? '';
+    if (defined('SHAARLI_ROOT_URL') && null !== SHAARLI_ROOT_URL) {
+        return rtrim(SHAARLI_ROOT_URL, '/') . '/';
+    }
+
+    $scriptname = !empty($server['SCRIPT_NAME']) ? $server['SCRIPT_NAME'] : '/';
     if (endsWith($scriptname, 'index.php')) {
         $scriptname = substr($scriptname, 0, -9);
     }
@@ -392,7 +396,7 @@ function page_url($server)
         $scriptname = substr($scriptname, 0, -9);
     }
 
-    $route = ltrim($server['REQUEST_URI'] ?? '', $scriptname);
+    $route = preg_replace('@^' . $scriptname . '@', '', $server['REQUEST_URI'] ?? '');
     if (! empty($server['QUERY_STRING'])) {
         return index_url($server) . $route . '?' . $server['QUERY_STRING'];
     }
diff --git a/doc/md/Shaarli-configuration.md b/doc/md/Shaarli-configuration.md
index 14eec7b2..263fb761 100644
--- a/doc/md/Shaarli-configuration.md
+++ b/doc/md/Shaarli-configuration.md
@@ -7,7 +7,7 @@ Once your Shaarli instance is installed, the file `data/config.json.php` is gene
 - its values override those defined in `index.php`
 - it is wrapped in a PHP comment so that its contents are never served by the web server, regardless of configuration
 
-**Do not edit configuration options in index.php! Your changes would be lost.** 
+**Do not edit configuration options in index.php! Your changes would be lost.**
 
 ## Tools menu
 
@@ -135,71 +135,72 @@ Some settings can be configured directly from a web browser by accesing the `Too
 ## Settings
 
 ### Credentials
- 
+
 _These settings should not be edited_
 
-- **login**: Login username.  
-- **hash**: Generated password hash.  
+- **login**: Login username.
+- **hash**: Generated password hash.
 - **salt**: Password salt.
 
 ### General
 
-- **title**: Shaarli's instance title.  
-- **header_link**: Link to the homepage.  
-- **links_per_page**: Number of Shaares displayed per page.  
-- **timezone**: See [the list of supported timezones](http://php.net/manual/en/timezones.php).  
+- **title**: Shaarli's instance title.
+- **header_link**: Link to the homepage.
+- **links_per_page**: Number of Shaares displayed per page.
+- **timezone**: See [the list of supported timezones](http://php.net/manual/en/timezones.php).
 - **enabled_plugins**: List of enabled plugins.
 - **default_note_title**: Default title of a new note.
 - **retrieve_description** (boolean): If set to true, for every new Shaare Shaarli will try to retrieve the description and keywords from the HTML meta tags.
+- **root_url**: Overrides automatic discovery of Shaarli instance's URL (e.g.) `https://sub.domain.tld/shaarli-folder/`.
 
 ### Security
 
-- **session_protection_disabled**: Disable session cookie hijacking protection (not recommended). 
-  It might be useful if your IP adress often changes.  
-- **ban_after**: Failed login attempts before being IP banned.  
-- **ban_duration**: IP ban duration in seconds.  
-- **open_shaarli**: Anyone can add a new Shaare while logged out if enabled.  
-- **trusted_proxies**: List of trusted IP which won't be banned after failed login attemps. Useful if Shaarli is behind a reverse proxy.  
+- **session_protection_disabled**: Disable session cookie hijacking protection (not recommended).
+  It might be useful if your IP adress often changes.
+- **ban_after**: Failed login attempts before being IP banned.
+- **ban_duration**: IP ban duration in seconds.
+- **open_shaarli**: Anyone can add a new Shaare while logged out if enabled.
+- **trusted_proxies**: List of trusted IP which won't be banned after failed login attemps. Useful if Shaarli is behind a reverse proxy.
 - **allowed_protocols**: List of allowed protocols in shaare URLs or markdown-rendered descriptions. Useful if you want to store `javascript:` links (bookmarklets) in Shaarli (default: `["ftp", "ftps", "magnet"]`).
 
 ### Resources
 
-- **data_dir**: Data directory.  
-- **datastore**: Shaarli's Shaares database file path.  
+- **data_dir**: Data directory.
+- **datastore**: Shaarli's Shaares database file path.
 - **history**: Shaarli's operation history file path.
-- **updates**: File path for the ran updates file.  
-- **log**: Log file path.  
-- **update_check**: Last update check file path.  
-- **raintpl_tpl**: Templates directory.  
-- **raintpl_tmp**: Template engine cache directory.  
-- **thumbnails_cache**: Thumbnails cache directory.  
-- **page_cache**: Shaarli's internal cache directory.  
+- **updates**: File path for the ran updates file.
+- **log**: Log file path.
+- **update_check**: Last update check file path.
+- **raintpl_tpl**: Templates directory.
+- **raintpl_tmp**: Template engine cache directory.
+- **thumbnails_cache**: Thumbnails cache directory.
+- **page_cache**: Shaarli's internal cache directory.
 - **ban_file**: Banned IP file path.
 
 ### Translation
 
 - **language**: translation language (also see [Translations](Translations))
-    - **auto** (default): The translation language is chosen from the browser locale. 
-    It means that the language can be different for 2 different visitors depending on their locale.  
+    - **auto** (default): The translation language is chosen from the browser locale.
+    It means that the language can be different for 2 different visitors depending on their locale.
     - **en**: Use the English translation.
     - **fr**: Use the French translation.
-- **mode**: 
+- **mode**:
     - **auto** or **php** (default): Use the PHP implementation of gettext (slower)
-    - **gettext**: Use PHP builtin gettext extension 
+    - **gettext**: Use PHP builtin gettext extension
     (faster, but requires `php-gettext` to be installed and to reload the web server on update)
-- **extension**: Translation extensions for custom themes or plugins. 
+- **extension**: Translation extensions for custom themes or plugins.
 Must be an associative array: `translation domain => translation path`.
 
 ### Updates
 
-- **check_updates**: Enable or disable update check to the git repository.  
-- **check_updates_branch**: Git branch used to check updates (e.g. `stable` or `master`).  
+- **check_updates**: Enable or disable update check to the git repository.
+- **check_updates_branch**: Git branch used to check updates (e.g. `stable` or `master`).
 - **check_updates_interval**: Look for new version every N seconds (default: every day).
 
 ### Privacy
 
-- **default_private_links**: Check the private checkbox by default for every new Shaare.  
-- **hide_public_links**: All Shaares are hidden while logged out.  
+- **default_private_links**: Check the private checkbox by default for every new Shaare.
+- **hide_public_links**: All Shaares are hidden while logged out.
 - **force_login**: if **hide_public_links** and this are set to `true`, all anonymous users are redirected to the login page.
 - **hide_timestamps**: Timestamps are hidden.
 - **remember_user_default**: Default state of the login page's *remember me* checkbox
@@ -207,14 +208,14 @@ Must be an associative array: `translation domain => translation path`.
 
 ### Feed
 
-- **rss_permalinks**: Enable this to redirect RSS links to Shaarli's permalinks instead of shaared URL.  
+- **rss_permalinks**: Enable this to redirect RSS links to Shaarli's permalinks instead of shaared URL.
 - **show_atom**: Display ATOM feed button.
 
 ### Thumbnail
 
-- **enable_thumbnails**: Enable or disable thumbnail display.  
+- **enable_thumbnails**: Enable or disable thumbnail display.
 - **enable_localcache**: Enable or disable local cache.
 
 ## Plugins configuration
 
-See [Plugins](Plugins.md)
\ No newline at end of file
+See [Plugins](Plugins.md)
diff --git a/index.php b/index.php
index 869f42de..b10397dd 100644
--- a/index.php
+++ b/index.php
@@ -35,6 +35,9 @@ use Slim\App;
 
 $conf = new ConfigManager();
 
+// Manually override root URL for complex server configurations
+define('SHAARLI_ROOT_URL', $conf->get('general.root_url', null));
+
 // In dev mode, throw exception on any warning
 if ($conf->get('dev.debug', false)) {
     // See all errors (for debugging only)
diff --git a/tests/http/HttpUtils/IndexUrlTest.php b/tests/http/HttpUtils/IndexUrlTest.php
index 73d33cd4..cce45c51 100644
--- a/tests/http/HttpUtils/IndexUrlTest.php
+++ b/tests/http/HttpUtils/IndexUrlTest.php
@@ -5,12 +5,14 @@
 
 namespace Shaarli\Http;
 
+use PHPUnit\Framework\TestCase;
+
 require_once 'application/http/HttpUtils.php';
 
 /**
  * Unitary tests for index_url()
  */
-class IndexUrlTest extends \PHPUnit\Framework\TestCase
+class IndexUrlTest extends TestCase
 {
     /**
      * If on the main page, remove "index.php" from the URL resource
@@ -103,4 +105,36 @@ class IndexUrlTest extends \PHPUnit\Framework\TestCase
             )
         );
     }
+
+    /**
+     * The route is stored in REQUEST_URI and subfolder
+     */
+    public function testPageUrlWithRouteUnderSubfolder()
+    {
+        $this->assertEquals(
+            'http://host.tld/subfolder/picture-wall',
+            page_url(
+                array(
+                    'HTTPS' => 'Off',
+                    'SERVER_NAME' => 'host.tld',
+                    'SERVER_PORT' => '80',
+                    'SCRIPT_NAME' => '/subfolder/index.php',
+                    'REQUEST_URI' => '/subfolder/picture-wall',
+                )
+            )
+        );
+
+        $this->assertEquals(
+            'http://host.tld/subfolder/admin/picture-wall',
+            page_url(
+                array(
+                    'HTTPS' => 'Off',
+                    'SERVER_NAME' => 'host.tld',
+                    'SERVER_PORT' => '80',
+                    'SCRIPT_NAME' => '/subfolder/admin/index.php',
+                    'REQUEST_URI' => '/subfolder/admin/picture-wall',
+                )
+            )
+        );
+    }
 }
diff --git a/tests/http/HttpUtils/IndexUrlTestWithConstant.php b/tests/http/HttpUtils/IndexUrlTestWithConstant.php
new file mode 100644
index 00000000..15ca3d72
--- /dev/null
+++ b/tests/http/HttpUtils/IndexUrlTestWithConstant.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shaarli\Http;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Test index_url with SHAARLI_ROOT_URL defined to override automatic retrieval.
+ * This should stay in its dedicated class to make sure to not alter other tests of the suite.
+ */
+class IndexUrlTestWithConstant extends TestCase
+{
+    public static function setUpBeforeClass(): void
+    {
+        define('SHAARLI_ROOT_URL', 'http://other-host.tld/subfolder/');
+    }
+
+    /**
+     * The route is stored in REQUEST_URI and subfolder
+     */
+    public function testIndexUrlWithConstantDefined()
+    {
+        $this->assertEquals(
+            'http://other-host.tld/subfolder/',
+            index_url(
+                array(
+                    'HTTPS' => 'Off',
+                    'SERVER_NAME' => 'host.tld',
+                    'SERVER_PORT' => '80',
+                    'SCRIPT_NAME' => '/index.php',
+                    'REQUEST_URI' => '/picture-wall',
+                )
+            )
+        );
+
+        $this->assertEquals(
+            'http://other-host.tld/subfolder/',
+            index_url(
+                array(
+                    'HTTPS' => 'Off',
+                    'SERVER_NAME' => 'host.tld',
+                    'SERVER_PORT' => '80',
+                    'SCRIPT_NAME' => '/admin/index.php',
+                    'REQUEST_URI' => '/admin/picture-wall',
+                )
+            )
+        );
+    }
+}