Check for hostname

You can enter the Djatoka URL as a relative path or full hostname. I did hostname and didn't get any errors. But this function assumes it is a path and sticks http(s)://<SERVER NAME> in front which causes you to get a blank Jpeg when downloading the clip.

islandora.module

@@ -1540,9 +1540,12 @@ function islandora_entity_property_info() {
  */
 function islandora_download_clip(AbstractObject $object) {
   if (isset($_GET['clip'])) {
+    $url = $_GET['clip'];
+    if (!preg_match('/^https?:\/\//',$url)) {
       $is_https = isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) == 'on';
       $http_protocol = $is_https ? 'https' : 'http';
-    $url = $http_protocol . '://' . $_SERVER['HTTP_HOST'] . $_GET['clip'];
+      $url = $http_protocol . '://' . $_SERVER['HTTP_HOST'] . $url;
+    }
     $filename = $object->label;
     header("Content-Disposition: attachment; filename=\"{$filename}.jpg\"");
     header("Content-type: image/jpeg");