diff --git a/node_modules/c9/urls.js b/node_modules/c9/urls.js
index e1e9362c..7484194b 100644
--- a/node_modules/c9/urls.js
+++ b/node_modules/c9/urls.js
@@ -34,7 +34,8 @@ plugin.getBaseUrl = function(req, sourceBaseUrlPattern, targetBaseUrlPattern) {
         || req.host
         || req.url && req.url.replace(/^https?:\/\/([^/]*).*/, "$1")
         || req;
-    assert(typeof sourceHost === "string", "Not a valid request object: " + JSON.stringify(req));
+    if (typeof sourceHost !== "string")
+        throw new Error("Not a valid request object: " + req);
 
     var sourceHostMatcher = sourceBaseUrlPattern
         .replace(/^https?:\/\//, "")