Add $config['attachments']['process_links'] to allow disabling processing of mentioned URL links for attachment info (oEmbed lookups) and dereferencing of redirects that we didn't have shortened ourselves.

This option may be useful for intranet sites that don't have direct access to the internet, as they may be unable to successfully fetch those resources.

classes/File_redirection.php

@@ -139,6 +139,7 @@ class File_redirection extends Memcached_DataObject
      * reached.
      *
      * @param string $in_url
+     * @param boolean $discover true to attempt dereferencing the redirect if we don't know it already
      * @return mixed one of:
      *         string - target URL, if this is a direct link or a known redirect
      *         array - redirect info if this is an *unknown* redirect:
@@ -150,7 +151,7 @@ class File_redirection extends Memcached_DataObject
      *                size (optional): byte size from Content-Length header
      *                time (optional): timestamp from Last-Modified header
      */
-    public function where($in_url) {
+    public function where($in_url, $discover=true) {
         // let's see if we know this...
         $a = File::staticGet('url', $in_url);
 
@@ -166,8 +167,13 @@ class File_redirection extends Memcached_DataObject
             }
         }
 
-        $ret = File_redirection::lookupWhere($in_url);
-        return $ret;
+        if ($discover) {
+            $ret = File_redirection::lookupWhere($in_url);
+            return $ret;
+        } else {
+            // No manual dereferencing; leave the unknown URL as is.
+            return $in_url;
+        }
     }
 
     /**