Add %%lookfor%% token support to search forwarding.

config/vufind/searchbox.ini

@@ -9,7 +9,10 @@ combinedHandlers = false
 ; of settings with the following keys:
 ;
 ; type[] = "VuFind" for an internal search module or "External" for an external URL
-; target[] = Search class ID for "VuFind" type, URL for "External" type
+; target[] = Search class ID for "VuFind" type, URL for "External" type; by default,
+;            the user's search terms will be appended to the end of the URL in
+;            "External" mode. You may use a %%lookfor%% placeholder string in the
+;            URL to force the query to be injected at a specific position.
 ; label[] = Label for this value (subject to translation)
 [CombinedHandlers]
 type[] = VuFind

module/VuFind/src/VuFind/Controller/CombinedController.php

@@ -245,7 +245,10 @@ class CombinedController extends AbstractSearch
             return $this->redirect()->toUrl($base . '?' . http_build_query($params));
         case 'External':
             $lookfor = $this->params()->fromQuery('lookfor');
-            return $this->redirect()->toUrl($target . urlencode($lookfor));
+            $finalTarget = (false === strpos($target, '%%lookfor%%'))
+                ? $target . urlencode($lookfor)
+                : str_replace('%%lookfor%%', urlencode($lookfor), $target);
+            return $this->redirect()->toUrl($finalTarget);
         default:
             // If parameters are completely missing, just redirect to home instead
             // of throwing an error; this is possibly a misbehaving crawler that