capaj / uwebsockets

Highly scalable WebSocket server library

`µWS` is one of the most lightweight, efficient & scalable WebSocket server implementations available. It features an easy-to-use, fully async object-oriented interface and scales to millions of connections using only a fraction of memory compared to the competition. License is zlib/libpng (very permissive & suits commercial applications).

• Linux, OS X & Windows support.
• Built-in load balancing and multi-core scalability.
• SSL/TLS support & integrates with foreign HTTPS servers.
• Permessage-deflate built-in.
• Node.js binding exposed as the well-known ws interface.
• Optional engine in projects like Socket.IO, Primus & SocketCluster.

Benchmarks table - validate

Implementation	Memory scaling	Connection performance	Short message throughput	Huge message throughput
libwebsockets master(1.7-1.8)	µWS is 14x as lightweight	µWS is equal in performance	µWS is 3x as performant	µWS is equal in performance
ws v1.1.0 + binary addons	µWS is 47x as lightweight	µWS is 18x as performant	µWS is 33x as performant	µWS is 2x as performant
WebSocket++ v0.7.0	µWS is 63x as lightweight	µWS is 4x as performant	µWS is 3x as performant	µWS is 2x as performant

Benchmarks are run with default settings in all libraries, except for ws which is run with the native performance addons. The libwebsockets benchmark is a little bit outdated, I'm going to fill in new data points with version 2.0.

Usage

Node.js

We built µWS with the existing Node.js infrastructure in mind. That's why we target the widespread ws interface, allowing us to seamlessly integrate with projects like SocketCluster, Socket.IO & Primus.

• Read the ws documentation
• Read the Primus transformer documentation

SocketCluster

Use the new wsEngine: 'uws' option like so:

var socketCluster = new SocketCluster({ wsEngine: 'uws' });

We've worked closely together with the SocketCluster team and aim to bring you µWS as the default WebSocket engine in SocketCluster 5.

Socket.IO

Use the new wsEngine: 'uws' option like so:

var io = require('socket.io')(80, { wsEngine: 'uws' });

This option has not yet been released, one alternative way of enabling uws in current versions of Socket.IO is:

var io = require('socket.io')(80);
io.engine.ws = new require('uws').Server({
    noServer: true,
    clientTracking: false,
    perMessageDeflate: false
});

Primus

Set 'uws' as transformer:

var primus = new Primus(server, { transformer: 'uws' });

ws

If your code directly relies on ws you can simply swap require('ws') with require('uws'):

var WebSocketServer = require('uws').Server; /* you replace 'ws' with 'uws' */
var wss = new WebSocketServer({ port: 8080 });

wss.on('connection', function (ws) {
    ws.on('message', function (message) {
        console.log('received: ' + message);
    });

    ws.send('something');
});

C++

For maximum performance and memory scaling the native interface is recommended. Look in the examples folder for threading and load balancing examples. There is no documentation written yet but a bright person like you will have no problem just reading the header file.

int main()
{
    /* this is an echo server that properly passes every supported Autobahn test */
    uWS::Server server(3000);
    server.onConnection([](uWS::Socket socket) {
        cout << "[Connection] clients: " << ++connections << endl;
    });

    server.onMessage([](uWS::Socket socket, const char *message, size_t length, uWS::OpCode opCode) {
        socket.send((char *) message, length, opCode);
    });

    server.onDisconnection([](uWS::Socket socket) {
        cout << "[Disconnection] clients: " << --connections << endl;
    });

    server.run();
}

Quality control

• Valgrind clean.
• Autobahn tests all pass.
• All Primus transformer integration tests pass.
• All Engine.IO server tests pass.
• Small & efficient code base.

Installation

Node.js

npm install --save uws

• Node.js 4.x, 5.x & 6.x supported
• Linux & Mac OS X 10.7+

Node.js is broken on Windows and needs to be fixed for us to support the platform

Manual compilation

If you for some reason want and/or need to build the Node.js addon from source:

• Jump to nodejs folder:
  • cd uWebSockets/nodejs
• Compile the project:
  • make

This populates the nodejs/dist folder with binaries.

Native developers

Dependencies

First of all you need to install the required dependencies. On Unix systems this is typically done via package managers, like homebrew in the case of OS X or dnf in the case of Fedora Linux. On Windows you need to search the web for pre-compiled binaries or simply compile the dependencies yourself.

• libuv 1.x
• OpenSSL 1.0.x
• CMake 3.x

Compilation

Obviously you will need to clone this repo to get the sources. We use CMake as build system.

• git clone https://github.com/alexhultman/uWebSockets.git && cd uWebSockets
• cmake .

Now, on Unix systems it should work by simply running make. Run [sudo] make install as you wish.

Windows, in all its glory

If you are running Windows you should now have a bunch of Visual Studio project files and one solution file. Open the solution file, now you need to make sure the header include paths and library paths are all set according to where you installed the dependencies. You might also need to change the names of the libraries being linked against, all according to the names of the installed library files. You know the drill.