[feature] Merge Engine.IO and Socket.IO handshake packets (#2833)

Author: darrachequesne

lib/index.js

@@ -245,18 +245,27 @@ Server.prototype.attach = function(srv, opts){
   // set origins verification
   opts.allowRequest = opts.allowRequest || this.checkRequest.bind(this);
 
-  // initialize engine
-  debug('creating engine.io instance with opts %j', opts);
-  this.eio = engine.attach(srv, opts);
+  var self = this;
+
+  var connectPacket = { type: parser.CONNECT, nsp: '/' };
+  this.encoder.encode(connectPacket, function (encodedPacket){
+    // the CONNECT packet will be merged with Engine.IO handshake,
+    // to reduce the number of round trips
+    opts.initialPacket = encodedPacket;
 
-  // attach static file serving
-  if (this._serveClient) this.attachServe(srv);
+    // initialize engine
+    debug('creating engine.io instance with opts %j', opts);
+    self.eio = engine.attach(srv, opts);
 
-  // Export http server
-  this.httpServer = srv;
+    // attach static file serving
+    if (self._serveClient) self.attachServe(srv);
 
-  // bind to engine events
-  this.bind(this.eio);
+    // Export http server
+    self.httpServer = srv;
+
+    // bind to engine events
+    self.bind(self.eio);
+  });
 
   return this;
 };

lib/socket.js

@@ -290,7 +290,11 @@ Socket.prototype.onconnect = function(){
   debug('socket connected - writing packet');
   this.nsp.connected[this.id] = this;
   this.join(this.id);
-  this.packet({ type: parser.CONNECT });
+  // the CONNECT packet for the default namespace
+  // has already been sent as an `initialPacket`
+  if (this.nsp.name !== '/') {
+    this.packet({ type: parser.CONNECT });
+  }
 };
 
 /**

test/socket.io.js

@@ -87,9 +87,6 @@ describe('socket.io', function(){
       srv.set('authorization', function(o, f) { f(null, false); });
 
       var socket = client(httpSrv);
-      socket.on('connect', function(){
-        expect().fail();
-      });
       socket.on('error', function(err) {
         expect(err).to.be('Not authorized');
         done();
@@ -2131,9 +2128,6 @@ describe('socket.io', function(){
       });
       srv.listen(function(){
         var socket = client(srv);
-        socket.on('connect', function(){
-          done(new Error('nope'));
-        });
         socket.on('error', function(err){
           expect(err).to.be('Authentication error');
           done();
@@ -2152,9 +2146,6 @@ describe('socket.io', function(){
       });
       srv.listen(function(){
         var socket = client(srv);
-        socket.on('connect', function(){
-          done(new Error('nope'));
-        });
         socket.on('error', function(err){
           expect(err).to.eql({ a: 'b', c: 3 });
           done();