enable keepAlive

Author: felicienfrancois

lib/proxy.js

@@ -48,8 +48,8 @@ Proxy.prototype.listen = function(options, callback) {
   this.silent = !!options.silent;
   this.httpPort = options.port || 8080;
   this.timeout = options.timeout || 0;
-  this.httpAgent = options.httpAgent || new http.Agent();
-  this.httpsAgent = options.httpsAgent || new https.Agent();
+  this.httpAgent = options.httpAgent || new http.Agent({ keepAlive: true });
+  this.httpsAgent = options.httpsAgent || new https.Agent({ keepAlive: true });
   this.forceSNI = !!options.forceSNI;
   if (this.forceSNI && !this.silent) {
     console.log('SNI enabled. Clients not supporting SNI may fail');
@@ -703,7 +703,10 @@ Proxy.prototype._onHttpServerRequest = function(isSSL, clientToProxyRequest, pro
       }
       ctx.serverToProxyResponse.headers['transfer-encoding'] = 'chunked';
       delete ctx.serverToProxyResponse.headers['content-length'];
-      ctx.serverToProxyResponse.headers['connection'] = 'close';
+      if (!ctx.serverToProxyResponse.headers['connection']) {
+    	var keepAlive = ctx.clientToProxyRequest.headers && ctx.clientToProxyRequest.headers['connection'] && ctx.clientToProxyRequest.headers['connection'].trim().toLowerCase() === 'keep-alive';
+        ctx.serverToProxyResponse.headers['connection'] = keepAlive ? 'keep-alive' : 'close';
+      }
       return self._onResponseHeaders(ctx, function (err) {
         if (err) {
           return self._onError('ON_RESPONSEHEADERS_ERROR', ctx, err);