BUGFIX: Index by alias, treated content (#203)

* BUGFIX:  Do not throw an error if index is not found

* BUGFIX Return an empty array if treatedContent is not an array

Author: sruegg

Classes/Driver/Version1/IndexDriver.php

@@ -52,10 +52,12 @@ public function deleteIndex($index)
     public function indexesByAlias($alias)
     {
         $response = $this->searchClient->request('GET', '/_alias/' . $alias);
-        if ($response->getStatusCode() !== 200) {
+        if ($response->getStatusCode() !== 200 && $response->getStatusCode() !== 404) {
             throw new Exception('The alias "' . $alias . '" was not found with some unexpected error... (return code: ' . $response->getStatusCode() . ')', 1383650137);
         }
 
-        return array_keys($response->getTreatedContent());
+        // return empty array if content from response cannot be read as an array
+        $treatedContent = $response->getTreatedContent();
+        return is_array($treatedContent) ? array_keys($treatedContent) : [];
     }
 }