diff --git a/changelog.md b/changelog.md
index 42da62c..0a7c16d 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,7 @@
+# v0.4.0
+## Add
+1. Add the property of `_res_data` to `http.ServerResponse` when come across proxy request error, such as the request is timeout or the backend is broken.
+
 # v0.3.0
 ## Add
 1. Add the parameter of `agent` to enable `keep-alive` in http request.
diff --git a/lib/proxy.js b/lib/proxy.js
index 5dc44e8..6fc6b38 100644
--- a/lib/proxy.js
+++ b/lib/proxy.js
@@ -69,17 +69,25 @@ const checkUrl = function(req, urlsToProxy, urlKeys, callback) {
  * @property {http.Agent=} agent The instance of the class of http.Agent. 
  */
 
+const _sendStatus = function(res, statusCode, message) {
+    res._res_code = message;
+    res.status(statusCode).end(message);
+};
 
 const DEFAULT_INIT_CONFIG = {
+    // eslint-disable-next-line no-unused-vars
     onError: function(err, agentUrl) {
         
     },
     dataPrepare: function(data) {
         return data;
     },
+    // eslint-disable-next-line no-unused-vars
     headerPrepare: function(req) {
         return {};
     },
+    beforeRequest: function() {},
+    afterRequest: function() {},
     timeout: 10000,
     jsonDisabled: false
 };
@@ -119,11 +127,11 @@ const _doProxy = function(options, agentUrl, req, res) {
         proxyReq.setNoDelay(true);
         proxyReq.setTimeout(timeout, function() {
             proxyReq.abort();
-            res.status(504).end('proxy ' + agentUrl +' timeout');
+            _sendStatus(res, 504, 'proxy ' + agentUrl +' timeout');
         });
         proxyReq.on('error', function(err) {//TODO check
             slogger.error('proxy ' + agentUrl +' error',err);
-            res.status(500).end('proxy ' + agentUrl +' error');
+            _sendStatus(res, 500, 'proxy ' + agentUrl +' error');
         });
 
         req.pipe(proxyReq);
@@ -178,7 +186,7 @@ const _doProxy = function(options, agentUrl, req, res) {
     apiGateWayReq.on('error', function(err) {
         slogger.error('request proxy http interface failed', err, reqOptions);
         if (err.code === 'ESOCKETTIMEDOUT' || err.code === 'ETIMEDOUT' ) { //request timeout
-            return res.status(504).end('proxy ' + agentUrl +' timeout');
+            return _sendStatus(res, 504, 'proxy ' + agentUrl +' timeout');
         }
         onError(err, agentUrl);
     });
@@ -204,7 +212,7 @@ module.exports = function doProxy(options) {
             if (err) {
                 const path = req.path;
                 slogger.error('proxy ' + path +' failed:', err);
-                return res.status(502).end('proxy ' + path +' failed: ' + err);
+                return _sendStatus(res, 502, 'proxy ' + path +' failed: ' + err);
             }
             if (!backUrl) {
                 return next();
diff --git a/package.json b/package.json
index 8f39783..a937d09 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "http-request-proxy",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "The middleware for proxying request in express",
   "main": "index.js",
   "directories": {