LearningWebRTC实例源码

# 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. See http://websockets.github.io/ws/ for the full reports. ## 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 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. ## API Docs See [`/doc/ws.md`](https://github.com/websockets/ws/blob/master/doc/ws.md) for Node.js-like docs for the ws classes. ## WebSocket compression `ws` supports the [permessage-deflate extension][permessage-deflate] 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: ```js const WebSocket = require('ws'); const wss = new WebSocket.Server({ perMessageDeflate: false, port: 8080 }); ``` On the client: ```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, flags) { // flags.binary will be set if a binary data is received. // flags.masked will be set if the data was masked. }); ``` ### 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); }); ``` ### Server example ```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'); }); ``` ### Broadcast example ```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); } }); }); }); ``` ### ExpressJS example ```js 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 http://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); }); ``` ### 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, flags) { console.log(`Roundtrip time: ${Date.now() - data} ms`, flags); 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 */ } ``` ## Changelog We're using the GitHub [`releases`](https://github.com/websockets/ws/releases) for changelog entries. ## License [MIT](LICENSE) [permessage-deflate]: https://tools.ietf.org/html/rfc7692