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

Author: Tofandel

lib/application.js

@@ -26,6 +26,8 @@ var resolve = require('path').resolve;
 var once = require('once')
 var Router = require('router');
 var setPrototypeOf = require('setprototypeof')
+var resProto = require('./response')
+var reqProto = require('./request')
 
 /**
  * Module variables.
@@ -48,6 +50,35 @@ var app = exports = module.exports = {};
 
 var trustProxyDefaultSymbol = '@@symbol:trust_proxy_default';
 
+function setPrototypeUntil(obj, proto, until) {
+  var currentProto = proto;
+  until = until || proto;
+  var last = Object.getPrototypeOf(until);
+  while (currentProto && currentProto !== last) {
+    Object.keys(currentProto).forEach((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: () => {
+      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: (v) => {
+      proto[key] = v
+    }
+  })
+}
 /**
  * Initialize the server.
  *
@@ -168,8 +199,8 @@ 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 +263,8 @@ 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);
       });
     });