Fix inheritance should not overwrite the methods of http.ServerResponse and http.IncomingMessage

Author: Tofandel

lib/application.js

@@ -25,7 +25,10 @@ var merge = require('utils-merge');
 var resolve = require('path').resolve;
 var once = require('once')
 var Router = require('router');
+var setPrototypeUntil = require('./setPrototypeUntil')
 var setPrototypeOf = require('setprototypeof')
+var resProto = require('./response')
+var reqProto = require('./request')
 
 /**
  * Module variables.
@@ -117,8 +120,6 @@ app.defaultConfiguration = function defaultConfiguration() {
     }
 
     // inherit protos
-    setPrototypeOf(this.request, parent.request)
-    setPrototypeOf(this.response, parent.response)
     setPrototypeOf(this.engines, parent.engines)
     setPrototypeOf(this.settings, parent.settings)
   });
@@ -168,8 +169,8 @@ app.handle = function handle(req, res, callback) {
   res.req = req;
 
   // alter the prototypes
-  setPrototypeOf(req, this.request)
-  setPrototypeOf(res, this.response)
+  setPrototypeUntil(req, this.request, reqProto)
+  setPrototypeUntil(res, this.response, resProto)
 
   // setup locals
   if (!res.locals) {
@@ -232,8 +233,8 @@ app.use = function use(fn) {
     router.use(path, function mounted_app(req, res, next) {
       var orig = req.app;
       fn.handle(req, res, function (err) {
-        setPrototypeOf(req, orig.request)
-        setPrototypeOf(res, orig.response)
+        setPrototypeUntil(req, orig.request)
+        setPrototypeUntil(res, orig.response)
         next(err);
       });
     });

lib/setPrototypeUntil.js

@@ -0,0 +1,32 @@
+
+function setPrototypeUntil(obj, proto, until) {
+  var currentProto = proto;
+  until = until || proto;
+  var last = Object.getPrototypeOf(until);
+  while (currentProto && currentProto !== last) {
+    Object.keys(currentProto).forEach(function (key) {
+      setPrototypeKey(obj, proto, key, until)
+    });
+    currentProto = Object.getPrototypeOf(currentProto)
+  }
+}
+
+function setPrototypeKey(obj, proto, key, until) {
+  Object.defineProperty(obj, key, {
+    configurable: true,
+    enumerable: proto.propertyIsEnumerable(key),
+    get: function () {
+      var desc = Object.getOwnPropertyDescriptor(until, key)
+      if (desc && typeof desc.get === 'function') {
+        // property defined with defineGetter, we need to change the `this` of the getter accordingly
+        return desc.get.call(obj)
+      }
+      return proto[key]
+    },
+    set: function (v) {
+      proto[key] = v
+    }
+  })
+}
+
+module.exports = setPrototypeUntil

test/app.response.js

@@ -139,5 +139,28 @@ describe('app', function(){
         .get('/sub/foo')
         .expect(200, 'FOO', cb)
     })
+
+    it('should inherit parent app', function (done) {
+      var app1 = express()
+      var app2 = express()
+      var cb = after(1, done)
+
+      app2.request.foo = 'bar';
+      app1.response.shout = function (str) {
+        this.setHeader('foo', this.req.foo)
+        this.send(str.toUpperCase())
+      }
+
+      app1.use('/sub', app2)
+
+      app2.get('/', function (req, res) {
+        res.shout('foo')
+      })
+
+      request(app1)
+        .get('/sub')
+        .expect('foo', 'bar')
+        .expect(200, 'FOO', cb)
+    })
   })
 })