Add flow control

Author: indexzero

lib/node-http-proxy/http-proxy.js

@@ -224,12 +224,22 @@ HttpProxy.prototype.proxyRequest = function (req, res, buffer) {
     response.on('data', function (chunk) {
       if (req.method !== 'HEAD' && res.writable) {
         try {
-          res.write(chunk);
+          var flushed = res.write(chunk);
         } 
         catch (ex) {
           console.error("res.write error: %s", ex.message);
+          
           try { res.end() } 
-          catch (ex) { console.error("res.write error: %s", ex.message) }
+          catch (ex) { console.error("res.end error: %s", ex.message) }
+          
+          return;
+        }
+        
+        if (!flushed) {
+          response.pause();
+          res.once('drain', function () {
+            response.resume();
+          });
         }
       }
     });
@@ -265,7 +275,13 @@ HttpProxy.prototype.proxyRequest = function (req, res, buffer) {
   //
   req.on('data', function (chunk) {
     if (!errState) {
-      reverseProxy.write(chunk);
+      var flushed = reverseProxy.write(chunk);
+      if (!flushed) {
+        req.pause();
+        reverseProxy.once('drain', function () {
+          req.resume();
+        });
+      }
     }
   });
 
@@ -334,8 +350,14 @@ HttpProxy.prototype._forwardRequest = function (req) {
   // the proxied request come in
   //
   req.on('data', function (chunk) {
-    forwardProxy.write(chunk);
-  })
+    var flushed = forwardProxy.write(chunk);
+    if (!flushed) {
+      req.pause();
+      forwardProxy.once('drain', function () {
+        req.resume();
+      });
+    }
+  });
 
   //
   // At the end of the client request, we are going to 
@@ -357,7 +379,7 @@ HttpProxy.prototype._forwardRequest = function (req) {
 //
 HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer) {
   var self      = this,
-      outgoing  = new(this.target.base);
+      outgoing  = new(this.target.base),
       listeners = {},
       errState  = false,
       CRLF      = '\r\n';
@@ -420,7 +442,13 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
       if (reverseProxy.incoming.socket.writable) {
         try {
           self.emit('websocket:outgoing', req, socket, head, data);
-          reverseProxy.incoming.socket.write(data);
+          var flushed = reverseProxy.incoming.socket.write(data);
+          if (!flushed) {
+            proxySocket.pause();
+            reverseProxy.incoming.socket.once('drain', function () {
+              proxySocket.resume();
+            });
+          }
         }
         catch (ex) {
           detach();
@@ -437,7 +465,13 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
     reverseProxy.incoming.socket.on('data', listeners.onOutgoing = function (data) {
       try {
         self.emit('websocket:incoming', reverseProxy, reverseProxy.incoming, head, data);
-        proxySocket.write(data);
+        var flushed = proxySocket.write(data);
+        if (!flushed) {
+          reverseProxy.incoming.socket.pause();
+          proxySocket.once('drain', function () {
+            reverseProxy.incoming.socket.resume();
+          });
+        }
       }
       catch (ex) {
         detach();
@@ -595,7 +629,13 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
         //
         self.emit('websocket:handshake', req, socket, head, sdata, data);
         socket.write(sdata);
-        socket.write(data);
+        var flushed = socket.write(data);
+        if (!flushed) {
+          reverseProxy.socket.pause();
+          socket.once('drain', function () {
+            reverseProxy.socket.resume();
+          });
+        }
       }
       catch (ex) {
         //
@@ -620,7 +660,9 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
 
   try {
     //
-    // Attempt to write the upgrade-head to the reverseProxy request.
+    // Attempt to write the upgrade-head to the reverseProxy 
+    // request. This is small, and there's only ever one of 
+    // it; no need for pause/resume.
     //
     reverseProxy.write(head);
   }