CDPT-2418 Remove trailing slash from document urls. (#805)

* CDPT-2418 Remove trailing slash from document urls.

* Revert ingress change

* Update ingress.tpl.yml

public/app/themes/clarity/inc/admin/plugins/wp-document-revisions.php

@@ -20,6 +20,7 @@ class WPDocumentRevisions
 
     private $home_url = '';
     private $site_url = '';
+    private $document_url_regex = '';
     private $wp_document_revisions = null;
 
     public function __construct()
@@ -28,13 +29,18 @@ public function __construct()
         $this->site_url = get_site_url();
         $this->home_url = get_home_url();
 
+        // Set the document URL regex - optional home_url, followed by /documents/.
+        $this->document_url_regex = '/^(' . preg_quote($this->home_url, '/') . ')?\/documents/';
+
         // load hooks here, inside WP ecosys...
         $this->hooks();
     }
 
     public function hooks(): void
     {
         add_filter('document_permalink', [$this, 'filterPermalink'], 10, 2);
+        // Filter to remove trailing slash from the document's URL.
+        add_filter('user_trailingslashit', [$this, 'filterTrailingSlash'], 10, 2);
         // Filter using gzip, always return false, let nginx handle gzipping where necessary.
         add_filter('document_serve_use_gzip', '__return_false', null, 2);
         // Filter to retry missing files.
@@ -60,6 +66,29 @@ public function filterPermalink(string $link, null|object|array $document)
         return str_replace($this->site_url, $this->home_url, $link);
     }
 
+    /**
+     * Remove trailing slash from the document's URL.
+     *
+     * This is required because the site-wide permalink structure is set to include a trailing slash.
+     * Here, that default is overridden to remove the trailing slash for the document post type.
+     * 
+     * This affects the URL in various places, e.g.
+     * - the document's URL on the document edit screen.
+     * - the URL for document downloads.
+     * - document URLs accessed with a trailing slash will be redirected to remove it.
+     * 
+     * @param string $string The URL.
+     * @return string The filtered URL.
+     */
+    public function filterTrailingSlash($string)
+    {
+        if (preg_match($this->document_url_regex, $string)) {
+            return untrailingslashit($string);
+        }
+
+        return $string;
+    }
+
     /**
      * Extract the date from the file path.
      * 
@@ -134,7 +163,7 @@ public function retryFilesNotFound($file, $attachment_id)
 
         // Let's replace the date with the one from the attachment's guid.
         $new_file = str_replace($dates['file'], $dates['guid'], $file);
-        
+
         // If the new file exists, return it.
         if (is_file($new_file)) {
             return $new_file;