--- /dev/null
+# ws: a Node.js WebSocket library
+
+[](https://www.npmjs.com/package/ws)
+[](https://travis-ci.org/websockets/ws)
+[](https://ci.appveyor.com/project/lpinca/ws)
+[](https://coveralls.io/r/websockets/ws?branch=master)
+
+ws is a simple to use, blazing fast, and thoroughly tested WebSocket client
+and server implementation.
+
+Passes the quite extensive Autobahn test suite: [server][server-report],
+[client][client-report].
+
+**Note**: This module does not work in the browser. The client in the docs is a
+reference to a back end with the role of a client in the WebSocket
+communication. Browser clients must use the native
+[`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket) object.
+To make the same code work seamlessly on Node.js and the browser, you can use
+one of the many wrappers available on npm, like
+[isomorphic-ws](https://github.com/heineiuo/isomorphic-ws).
+
+## Table of Contents
+
+* [Protocol support](#protocol-support)
+* [Installing](#installing)
+ + [Opt-in for performance and spec compliance](#opt-in-for-performance-and-spec-compliance)
+* [API docs](#api-docs)
+* [WebSocket compression](#websocket-compression)
+* [Usage examples](#usage-examples)
+ + [Sending and receiving text data](#sending-and-receiving-text-data)
+ + [Sending binary data](#sending-binary-data)
+ + [Simple server](#simple-server)
+ + [External HTTP/S server](#external-https-server)
+ + [Multiple servers sharing a single HTTP/S server](#multiple-servers-sharing-a-single-https-server)
+ + [Server broadcast](#server-broadcast)
+ + [echo.websocket.org demo](#echowebsocketorg-demo)
+ + [Other examples](#other-examples)
+* [Error handling best practices](#error-handling-best-practices)
+* [FAQ](#faq)
+ + [How to get the IP address of the client?](#how-to-get-the-ip-address-of-the-client)
+ + [How to detect and close broken connections?](#how-to-detect-and-close-broken-connections)
+ + [How to connect via a proxy?](#how-to-connect-via-a-proxy)
+* [Changelog](#changelog)
+* [License](#license)
+
+## Protocol support
+
+* **HyBi drafts 07-12** (Use the option `protocolVersion: 8`)
+* **HyBi drafts 13-17** (Current default, alternatively option `protocolVersion: 13`)
+
+## Installing
+
+```
+npm install --save ws
+```
+
+### Opt-in for performance and spec compliance
+
+There are 2 optional modules that can be installed along side with the ws
+module. These modules are binary addons which improve certain operations.
+Prebuilt binaries are available for the most popular platforms so you don't
+necessarily need to have a C++ compiler installed on your machine.
+
+- `npm install --save-optional bufferutil`: Allows to efficiently perform
+ operations such as masking and unmasking the data payload of the WebSocket
+ frames.
+- `npm install --save-optional utf-8-validate`: Allows to efficiently check
+ if a message contains valid UTF-8 as required by the spec.
+
+## API docs
+
+See [`/doc/ws.md`](./doc/ws.md) for Node.js-like docs for the ws classes.
+
+## WebSocket compression
+
+ws supports the [permessage-deflate extension][permessage-deflate] 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 disabled by default on the server and enabled by default on
+the client. It adds a significant overhead in terms of performance and memory
+consumption so we suggest to enable it only if it is really needed.
+
+Note that Node.js has a variety of issues with high-performance compression,
+where increased concurrency, especially on Linux, can lead to
+[catastrophic memory fragmentation][node-zlib-bug] and slow performance.
+If you intend to use permessage-deflate in production, it is worthwhile to set
+up a test representative of your workload and ensure Node.js/zlib will handle
+it with acceptable performance and memory usage.
+
+Tuning of permessage-deflate can be done via the options defined below. You can
+also use `zlibDeflateOptions` and `zlibInflateOptions`, which is passed directly
+into the creation of [raw deflate/inflate streams][node-zlib-deflaterawdocs].
+
+See [the docs][ws-server-options] for more options.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({
+ port: 8080,
+ perMessageDeflate: {
+ zlibDeflateOptions: { // See zlib defaults.
+ chunkSize: 1024,
+ memLevel: 7,
+ level: 3,
+ },
+ zlibInflateOptions: {
+ chunkSize: 10 * 1024
+ },
+ // Other options settable:
+ clientNoContextTakeover: true, // Defaults to negotiated value.
+ serverNoContextTakeover: true, // Defaults to negotiated value.
+ clientMaxWindowBits: 10, // Defaults to negotiated value.
+ serverMaxWindowBits: 10, // Defaults to negotiated value.
+ // Below options specified as default values.
+ concurrencyLimit: 10, // Limits zlib concurrency for perf.
+ threshold: 1024, // Size (in bytes) below which messages
+ // should not be compressed.
+ }
+});
+```
+
+The client will only use the extension if it is supported and enabled on the
+server. To always disable the extension on the client set the
+`perMessageDeflate` option to `false`.
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://www.host.com/path', {
+ perMessageDeflate: false
+});
+```
+
+## Usage examples
+
+### Sending and receiving text data
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('open', function open() {
+ ws.send('something');
+});
+
+ws.on('message', function incoming(data) {
+ console.log(data);
+});
+```
+
+### Sending binary data
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://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);
+});
+```
+
+### Simple server
+
+```js
+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');
+});
+```
+
+### External HTTP/S server
+
+```js
+const fs = require('fs');
+const https = require('https');
+const WebSocket = require('ws');
+
+const server = new https.createServer({
+ cert: fs.readFileSync('/path/to/cert.pem'),
+ key: fs.readFileSync('/path/to/key.pem')
+});
+const wss = new WebSocket.Server({ server });
+
+wss.on('connection', function connection(ws) {
+ ws.on('message', function incoming(message) {
+ console.log('received: %s', message);
+ });
+
+ ws.send('something');
+});
+
+server.listen(8080);
+```
+
+### Multiple servers sharing a single HTTP/S server
+
+```js
+const http = require('http');
+const WebSocket = require('ws');
+
+const server = http.createServer();
+const wss1 = new WebSocket.Server({ noServer: true });
+const wss2 = new WebSocket.Server({ noServer: true });
+
+wss1.on('connection', function connection(ws) {
+ // ...
+});
+
+wss2.on('connection', function connection(ws) {
+ // ...
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+ const pathname = url.parse(request.url).pathname;
+
+ if (pathname === '/foo') {
+ wss1.handleUpgrade(request, socket, head, function done(ws) {
+ wss1.emit('connection', ws, request);
+ });
+ } else if (pathname === '/bar') {
+ wss2.handleUpgrade(request, socket, head, function done(ws) {
+ wss2.emit('connection', ws, request);
+ });
+ } else {
+ socket.destroy();
+ }
+});
+
+server.listen(8080);
+```
+
+### Server broadcast
+
+```js
+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);
+ }
+ });
+ });
+});
+```
+
+### echo.websocket.org demo
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('wss://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) {
+ console.log(`Roundtrip time: ${Date.now() - data} ms`);
+
+ setTimeout(function timeout() {
+ ws.send(Date.now());
+ }, 500);
+});
+```
+
+### Other examples
+
+For a full example with a browser client communicating with a ws server, see the
+examples folder.
+
+Otherwise, see the test cases.
+
+## Error handling best practices
+
+```js
+// 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 */ }
+```
+
+## FAQ
+
+### How to get the IP address of the client?
+
+The remote IP address can be obtained from the raw socket.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws, req) {
+ const ip = req.connection.remoteAddress;
+});
+```
+
+When the server runs behind a proxy like NGINX, the de-facto standard is to use
+the `X-Forwarded-For` header.
+
+```js
+wss.on('connection', function connection(ws, req) {
+ const ip = req.headers['x-forwarded-for'].split(/\s*,\s*/)[0];
+});
+```
+
+### How to detect and close broken connections?
+
+Sometimes the link between the server and the client can be interrupted in a
+way that keeps both the server and the client unaware of the broken state of the
+connection (e.g. when pulling the cord).
+
+In these cases ping messages can be used as a means to verify that the remote
+endpoint is still responsive.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+function noop() {}
+
+function heartbeat() {
+ this.isAlive = true;
+}
+
+wss.on('connection', function connection(ws) {
+ ws.isAlive = true;
+ ws.on('pong', heartbeat);
+});
+
+const interval = setInterval(function ping() {
+ wss.clients.forEach(function each(ws) {
+ if (ws.isAlive === false) return ws.terminate();
+
+ ws.isAlive = false;
+ ws.ping(noop);
+ });
+}, 30000);
+```
+
+Pong messages are automatically sent in response to ping messages as required
+by the spec.
+
+### How to connect via a proxy?
+
+Use a custom `http.Agent` implementation like [https-proxy-agent][] or
+[socks-proxy-agent][].
+
+## Changelog
+
+We're using the GitHub [releases][changelog] for changelog entries.
+
+## License
+
+[MIT](LICENSE)
+
+[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
+[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
+[client-report]: http://websockets.github.io/ws/autobahn/clients/
+[server-report]: http://websockets.github.io/ws/autobahn/servers/
+[permessage-deflate]: https://tools.ietf.org/html/rfc7692
+[changelog]: https://github.com/websockets/ws/releases
+[node-zlib-bug]: https://github.com/nodejs/node/issues/8871
+[node-zlib-deflaterawdocs]: https://nodejs.org/api/zlib.html#zlib_zlib_createdeflateraw_options
+[ws-server-options]: https://github.com/websockets/ws/blob/master/doc/ws.md#new-websocketserveroptions-callback
projects / VSoRC / .git / blobdiff