diff --git a/src/serve_style.js b/src/serve_style.js
index a0d7629..aa17edb 100644
--- a/src/serve_style.js
+++ b/src/serve_style.js
@@ -21,6 +21,21 @@ const fixUrl = (req, url, publicUrl, opt_nokey) => {
 };
 
 
+// Return the query suffix from the original request
+const getQuery = (req, opt_nokey) => {
+  const queryParams = [];
+  if (!opt_nokey && req.query.key) {
+    queryParams.unshift(`key=${encodeURIComponent(req.query.key)}`);
+  }
+
+  let query = '';
+  if (queryParams.length) {
+    query = `?${queryParams.join('&')}`;
+  }
+
+  return query;
+}
+
 // Return the query suffix from the original request
 const getQuery = (req, opt_nokey) => {
   const queryParams = [];