From 2cc7d14c0bddfb6401b27e6a894ec664d6093da9 Mon Sep 17 00:00:00 2001
From: Aaron Zhang <aaronzhang1@gmail.com>
Date: Tue, 13 May 2014 14:18:36 -0400
Subject: [PATCH] Add express4 support to rearrangeMiddleware. Make sorting
 stable.

---
 README.md   |  3 +++
 lib/util.js | 19 +++++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 508e1a1..e1ebffe 100644
--- a/README.md
+++ b/README.md
@@ -154,6 +154,9 @@ exports = module.exports = server;
 exports.use = function() {
   app.use.apply(app, arguments);
 };
+
+// For Express 4, for grunt-express to access middleware stack
+exports._router = app._router;
 ```
 
 When `server` option is not set, `express` task will generate a plain `connect` object for you.
diff --git a/lib/util.js b/lib/util.js
index f324ffa..3c7351e 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -14,10 +14,25 @@ exports.makeServerTaskName = function makeServerTaskName(serverName, kind) {
   return 'express_' + serverName + '_' + kind;
 }
 
+// Sort middlewares by priority without changing order of middlewares
+// without specified priority.
 exports.rearrangeMiddleware = function rearrangeMiddleware(server) {
-  server.stack = (server.stack || []).sortBy(function(mw) {
-    return mw.handle.middlewarePriority || 99;
+  // middleware stack located at server._router for Express4
+  if (server._router) server = server._router;
+
+  var prioritySpecified = (server.stack || []).filter(function(mw) {
+    return (typeof mw.handle.middlewarePriority !== "undefined");
+  });
+
+  var priorityUnspecified = (server.stack || []).filter(function(mw) {
+    return (typeof mw.handle.middlewarePriority === "undefined");
   });
+
+  prioritySpecified = prioritySpecified.sortBy(function(mw) {
+    return mw.handle.middlewarePriority;
+  });
+
+  server.stack = prioritySpecified.concat(priorityUnspecified);
 }
 
 exports.watchModule = function watchModule(watcher) {