Updating websocket transport to be usable behind an haproxy load bala…

…ncer.

lib/socket.io/transports/websocket.js

@@ -29,6 +29,22 @@ WebSocket.prototype._onConnect = function(req, socket){
 	}
 
 	if (this.draft == 76){
+	/*  We need to send the 101 response immediately when using Draft 76 with
+		a load balancing proxy, such as HAProxy.  In order to protect an
+		unsuspecting non-websocket HTTP server, HAProxy will not send the
+		8-byte nonce through the connection until the Upgrade: WebSocket
+		request has been confirmed by the WebSocket server by a 101 response
+		indicating that the server can handle the upgraded protocol.  We
+		therefore must send the 101 response immediately, and then wait for
+		the nonce to be forwarded to us afterward in order to finish the
+		Draft 76 handshake.
+	*/
+
+		// If we don't have the nonce yet, wait for it.
+	    if (!(this.upgradeHead && this.upgradeHead.length >= 8)) {
+			this.waitingForNonce = true;
+	    }
+
 		var origin = this.request.headers.origin;
 
 		headers = [
@@ -51,12 +67,12 @@ WebSocket.prototype._onConnect = function(req, socket){
 			'WebSocket-Origin: ' + this.request.headers.origin,
 			'WebSocket-Location: ws://' + this.request.headers.host + this.request.url
 		];
-		
-		try {
-			this.connection.write(headers.concat('', '').join('\r\n'));
-		} catch(e){
-			this._onClose();
-		}
+	}
+
+	try {
+		this.connection.write(headers.concat('', '').join('\r\n'));
+	} catch(e){
+		this._onClose();
 	}
 
 	this.connection.addListener('end', function(){
@@ -67,12 +83,32 @@ WebSocket.prototype._onConnect = function(req, socket){
 		self._handle(data);
 	});
 
-	if (this._proveReception(headers)) this._payload();
+	if (this.waitingForNonce) {
+		// Since we will be receiving the binary nonce through the normal HTTP
+		// data event, set the connection to 'binary' temporarily
+		this.connection.setEncoding('binary');
+		this._headers = headers;
+	}
+	else {
+		if (this._proveReception(headers)) this._payload();
+	}
 };
 
 WebSocket.prototype._handle = function(data){
 	var chunk, chunks, chunk_count;
 	this.data += data;
+	if (this.waitingForNonce) {
+		if (this.data.length < 8) { return; }
+		// Restore the connection to utf8 encoding after receiving the nonce
+		this.connection.setEncoding('utf8');
+		this.waitingForNonce = false;
+		// Stuff the nonce into the location where it's expected to be
+		this.upgradeHead = this.data.substr(0,8);
+		this.data = this.data.substr(8);
+		if (this._proveReception(this._headers)) { this._payload(); }
+		return;
+	}
+
 	chunks = this.data.split('\ufffd');
 	chunk_count = chunks.length - 1;
 	for (var i = 0; i < chunk_count; i++){
@@ -117,7 +153,7 @@ WebSocket.prototype._proveReception = function(headers){
 		md5.update(this.upgradeHead.toString('binary'));
 
 		try {
-			this.connection.write(headers.concat('', '').join('\r\n') + md5.digest('binary'), 'binary');
+			this.connection.write(md5.digest('binary'), 'binary');
 		} catch(e){
 			this._onClose();
 		}