Prevent ServiceModule::Execute from compacting empty url

- Stop it from throwing warnings and notices all over the place.

classes/modules/ServiceModule.php

@@ -204,27 +204,31 @@ final class ServiceModule implements ModuleInterface
             $prefixHeader = array();
 
             for ($i = 0; $i < sizeof($params); $i++) {
-                if (Utils::mirror_external_uris($conf)) {
+                if ($params[$i] && Utils::mirror_external_uris($conf)) {
                     $params[$i] = Utils::uri2curie($this->altUri($params, $i));
                 }
             }
 
             $segmentConnector = "";
             for ($i = 0; $i < sizeof($params); $i++) {
-                Utils::curie2uri($params[$i]);
-                $auxPrefix = Utils::getPrefix($params[$i]);
-                if ($auxPrefix['ns'] != null) {
-                    $prefixHeader[] = $auxPrefix;
-                }
-                $args["arg" . $i] = $params[$i];
-                $args["all"] .= $segmentConnector . $params[$i];
-                if ($segmentConnector == "") {
-                    $segmentConnector = "/";
+                if ($params[$i]) {
+                    Utils::curie2uri($params[$i]);
+                    $auxPrefix = Utils::getPrefix($params[$i], $conf['ns']);
+
+                    if ($auxPrefix['ns'] != null) {
+                        $prefixHeader[] = $auxPrefix;
+                    }
+
+                    $args["arg" . $i] = $params[$i];
+                    $args["all"] .= $segmentConnector . $params[$i];
+
+                    if ($segmentConnector == "") {
+                        $segmentConnector = "/";
+                    }
                 }
             }
-            $results['params'] = $params;
-
 
+            $results['params'] = $params;
             $lodspk['home'] = $conf['basedir'];
             $lodspk['baseUrl'] = $conf['basedir'];
             $lodspk['module'] = 'service';