ws
is a simple to use, blazing fast, and thoroughly tested WebSocket client
and server implementation.
Passes the quite extensive Autobahn test suite. See https://websockets.github.com/ws for the full reports.
- HyBi drafts 07-12 (Use the option
protocolVersion: 8
) - HyBi drafts 13-17 (Current default, alternatively option
protocolVersion: 13
)
npm install --save ws
There are 2 optional modules that can be installed along side with the ws
module. These modules are binary addons which improve certain operations, but as
they are binary addons they require compilation which can fail if no c++
compiler is installed on the host system.
npm install --save bufferutil
: Improves internal buffer operations which allows for faster processing of masked WebSocket frames and general buffer operations.npm install --save utf-8-validate
: The specification requires validation of invalid UTF-8 chars, some of these validations could not be done in JavaScript hence the need for a binary addon. In most cases you will already be validating the input that you receive for security purposes leading to double validation. But if you want to be 100% spec-conforming and have fast validation of UTF-8 then this module is a must.
See /doc/ws.md
for Node.js-like docs for the ws classes.
ws
supports the permessage-deflate extension extension
which enables the client and server to negotiate a compression algorithm and
its parameters, and then selectively apply it to the data payloads of each
WebSocket message.
The extension is enabled by default but adds a significant overhead in terms of performance and memory comsumption. We suggest to use WebSocket compression only if it is really needed.
To disable the extension you can set the perMessageDeflate
option to false
.
On the server:
const WebSocket = require('ws');
const wss = new WebSocket.Server({
perMessageDeflate: false,
port: 8080
});
On the client:
const WebSocket = require('ws');
const ws = new WebSocket('ws:https://www.host.com/path', {
perMessageDeflate: false
});
const WebSocket = require('ws');
const ws = new WebSocket('ws:https://www.host.com/path');
ws.on('open', function open() {
ws.send('something');
});
ws.on('message', function incoming(data, flags) {
// flags.binary will be set if a binary data is received.
// flags.masked will be set if the data was masked.
});
const WebSocket = require('ws');
const ws = new WebSocket('ws:https://www.host.com/path');
ws.on('open', function open() {
const array = new Float32Array(5);
for (var i = 0; i < array.length; ++i) {
array[i] = i / 2;
}
ws.send(array);
});
const WebSocket = require('ws');
const wss = new WebSocket.Server({ port: 8080 });
wss.on('connection', function connection(ws) {
ws.on('message', function incoming(message) {
console.log('received: %s', message);
});
ws.send('something');
});
const WebSocket = require('ws');
const wss = new WebSocket.Server({ port: 8080 });
// Broadcast to all.
wss.broadcast = function broadcast(data) {
wss.clients.forEach(function each(client) {
if (client.readyState === WebSocket.OPEN) {
client.send(data);
}
});
};
wss.on('connection', function connection(ws) {
ws.on('message', function incoming(data) {
// Broadcast to everyone else.
wss.clients.forEach(function each(client) {
if (client !== ws && client.readyState === WebSocket.OPEN) {
client.send(data);
}
});
});
});
const express = require('express');
const http = require('http');
const url = require('url');
const WebSocket = require('ws');
const app = express();
app.use(function (req, res) {
res.send({ msg: "hello" });
});
const server = http.createServer(app);
const wss = new WebSocket.Server({ server });
wss.on('connection', function connection(ws) {
const location = url.parse(ws.upgradeReq.url, true);
// You might use location.query.access_token to authenticate or share sessions
// or ws.upgradeReq.headers.cookie (see https://stackoverflow.com/a/16395220/151312)
ws.on('message', function incoming(message) {
console.log('received: %s', message);
});
ws.send('something');
});
server.listen(8080, function listening() {
console.log('Listening on %d', server.address().port);
});
const WebSocket = require('ws');
const ws = new WebSocket('wss:https://echo.websocket.org/', {
origin: 'https://websocket.org'
});
ws.on('open', function open() {
console.log('connected');
ws.send(Date.now());
});
ws.on('close', function close() {
console.log('disconnected');
});
ws.on('message', function incoming(data, flags) {
console.log(`Roundtrip time: ${Date.now() - data} ms`, flags);
setTimeout(function timeout() {
ws.send(Date.now());
}, 500);
});
For a full example with a browser client communicating with a ws server, see the examples folder.
Otherwise, see the test cases.
// If the WebSocket is closed before the following send is attempted
ws.send('something');
// Errors (both immediate and async write errors) can be detected in an optional
// callback. The callback is also the only way of being notified that data has
// actually been sent.
ws.send('something', function ack(error) {
// If error is not defined, the send has been completed, otherwise the error
// object will indicate what failed.
});
// Immediate errors can also be handled with `try...catch`, but **note** that
// since sends are inherently asynchronous, socket write failures will *not* be
// captured when this technique is used.
try { ws.send('something'); }
catch (e) { /* handle error */ }
We're using the GitHub releases
for changelog entries.