mqtt stuff added
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node_modules/ws/README.md
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# ws: a Node.js WebSocket library
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[](https://www.npmjs.com/package/ws)
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[](https://travis-ci.org/websockets/ws)
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[](https://ci.appveyor.com/project/lpinca/ws)
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[](https://coveralls.io/r/websockets/ws?branch=master)
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ws is a simple to use, blazing fast, and thoroughly tested WebSocket client
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and server implementation.
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Passes the quite extensive Autobahn test suite: [server][server-report],
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[client][client-report].
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**Note**: This module does not work in the browser. The client in the docs is a
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reference to a back end with the role of a client in the WebSocket
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communication. Browser clients must use the native
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[`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket) object.
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## Table of Contents
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* [Protocol support](#protocol-support)
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* [Installing](#installing)
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+ [Opt-in for performance and spec compliance](#opt-in-for-performance-and-spec-compliance)
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* [API docs](#api-docs)
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* [WebSocket compression](#websocket-compression)
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* [Usage examples](#usage-examples)
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+ [Sending and receiving text data](#sending-and-receiving-text-data)
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+ [Sending binary data](#sending-binary-data)
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+ [Server example](#server-example)
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+ [Broadcast example](#broadcast-example)
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+ [ExpressJS example](#expressjs-example)
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+ [echo.websocket.org demo](#echowebsocketorg-demo)
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+ [Other examples](#other-examples)
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* [Error handling best practices](#error-handling-best-practices)
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* [FAQ](#faq)
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+ [How to get the IP address of the client?](#how-to-get-the-ip-address-of-the-client)
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+ [How to detect and close broken connections?](#how-to-detect-and-close-broken-connections)
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+ [How to connect via a proxy?](#how-to-connect-via-a-proxy)
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* [Changelog](#changelog)
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* [License](#license)
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## Protocol support
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* **HyBi drafts 07-12** (Use the option `protocolVersion: 8`)
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* **HyBi drafts 13-17** (Current default, alternatively option `protocolVersion: 13`)
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## Installing
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```
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npm install --save ws
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```
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### Opt-in for performance and spec compliance
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There are 2 optional modules that can be installed along side with the ws
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module. These modules are binary addons which improve certain operations.
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Prebuilt binaries are available for the most popular platforms so you don't
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necessarily need to have a C++ compiler installed on your machine.
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- `npm install --save-optional bufferutil`: Allows to efficiently perform
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operations such as masking and unmasking the data payload of the WebSocket
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frames.
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- `npm install --save-optional utf-8-validate`: Allows to efficiently check
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if a message contains valid UTF-8 as required by the spec.
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## API docs
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See [`/doc/ws.md`](./doc/ws.md) for Node.js-like docs for the ws classes.
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## WebSocket compression
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ws supports the [permessage-deflate extension][permessage-deflate] which
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enables the client and server to negotiate a compression algorithm and its
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parameters, and then selectively apply it to the data payloads of each
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WebSocket message.
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The extension is disabled by default on the server and enabled by default on
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the client. It adds a significant overhead in terms of performance and memory
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consumption so we suggest to enable it only if it is really needed.
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The client will only use the extension if it is supported and enabled on the
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server. To always disable the extension on the client set the
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`perMessageDeflate` option to `false`.
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```js
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const WebSocket = require('ws');
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const ws = new WebSocket('ws://www.host.com/path', {
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perMessageDeflate: false
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});
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```
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## Usage examples
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### Sending and receiving text data
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```js
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const WebSocket = require('ws');
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const ws = new WebSocket('ws://www.host.com/path');
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ws.on('open', function open() {
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ws.send('something');
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});
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ws.on('message', function incoming(data) {
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console.log(data);
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});
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```
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### Sending binary data
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```js
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const WebSocket = require('ws');
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const ws = new WebSocket('ws://www.host.com/path');
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ws.on('open', function open() {
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const array = new Float32Array(5);
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for (var i = 0; i < array.length; ++i) {
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array[i] = i / 2;
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}
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ws.send(array);
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});
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```
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### Server example
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```js
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const WebSocket = require('ws');
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const wss = new WebSocket.Server({ port: 8080 });
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wss.on('connection', function connection(ws) {
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ws.on('message', function incoming(message) {
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console.log('received: %s', message);
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});
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ws.send('something');
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});
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```
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### Broadcast example
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```js
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const WebSocket = require('ws');
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const wss = new WebSocket.Server({ port: 8080 });
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// Broadcast to all.
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wss.broadcast = function broadcast(data) {
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wss.clients.forEach(function each(client) {
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if (client.readyState === WebSocket.OPEN) {
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client.send(data);
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}
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});
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};
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wss.on('connection', function connection(ws) {
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ws.on('message', function incoming(data) {
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// Broadcast to everyone else.
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wss.clients.forEach(function each(client) {
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if (client !== ws && client.readyState === WebSocket.OPEN) {
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client.send(data);
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}
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});
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});
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});
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```
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### ExpressJS example
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```js
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const express = require('express');
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const http = require('http');
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const url = require('url');
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const WebSocket = require('ws');
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const app = express();
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app.use(function (req, res) {
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res.send({ msg: "hello" });
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});
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const server = http.createServer(app);
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const wss = new WebSocket.Server({ server });
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wss.on('connection', function connection(ws, req) {
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const location = url.parse(req.url, true);
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// You might use location.query.access_token to authenticate or share sessions
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// or req.headers.cookie (see http://stackoverflow.com/a/16395220/151312)
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ws.on('message', function incoming(message) {
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console.log('received: %s', message);
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});
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ws.send('something');
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});
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server.listen(8080, function listening() {
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console.log('Listening on %d', server.address().port);
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});
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```
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### echo.websocket.org demo
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```js
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const WebSocket = require('ws');
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const ws = new WebSocket('wss://echo.websocket.org/', {
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origin: 'https://websocket.org'
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});
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ws.on('open', function open() {
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console.log('connected');
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ws.send(Date.now());
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});
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ws.on('close', function close() {
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console.log('disconnected');
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});
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ws.on('message', function incoming(data) {
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console.log(`Roundtrip time: ${Date.now() - data} ms`);
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setTimeout(function timeout() {
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ws.send(Date.now());
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}, 500);
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});
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```
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### Other examples
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For a full example with a browser client communicating with a ws server, see the
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examples folder.
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Otherwise, see the test cases.
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## Error handling best practices
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```js
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// If the WebSocket is closed before the following send is attempted
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ws.send('something');
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// Errors (both immediate and async write errors) can be detected in an optional
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// callback. The callback is also the only way of being notified that data has
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// actually been sent.
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ws.send('something', function ack(error) {
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// If error is not defined, the send has been completed, otherwise the error
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// object will indicate what failed.
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});
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// Immediate errors can also be handled with `try...catch`, but **note** that
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// since sends are inherently asynchronous, socket write failures will *not* be
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// captured when this technique is used.
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try { ws.send('something'); }
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catch (e) { /* handle error */ }
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```
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## FAQ
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### How to get the IP address of the client?
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The remote IP address can be obtained from the raw socket.
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```js
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const WebSocket = require('ws');
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const wss = new WebSocket.Server({ port: 8080 });
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wss.on('connection', function connection(ws, req) {
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const ip = req.connection.remoteAddress;
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});
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```
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When the server runs behind a proxy like NGINX, the de-facto standard is to use
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the `X-Forwarded-For` header.
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```js
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wss.on('connection', function connection(ws, req) {
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const ip = req.headers['x-forwarded-for'];
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});
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```
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### How to detect and close broken connections?
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Sometimes the link between the server and the client can be interrupted in a
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way that keeps both the server and the client unaware of the broken state of the
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connection (e.g. when pulling the cord).
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In these cases ping messages can be used as a means to verify that the remote
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endpoint is still responsive.
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```js
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const WebSocket = require('ws');
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const wss = new WebSocket.Server({ port: 8080 });
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function heartbeat() {
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this.isAlive = true;
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}
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wss.on('connection', function connection(ws) {
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ws.isAlive = true;
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ws.on('pong', heartbeat);
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});
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const interval = setInterval(function ping() {
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wss.clients.forEach(function each(ws) {
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if (ws.isAlive === false) return ws.terminate();
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ws.isAlive = false;
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ws.ping('', false, true);
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});
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}, 30000);
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```
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Pong messages are automatically sent in response to ping messages as required
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by the spec.
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### How to connect via a proxy?
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Use a custom `http.Agent` implementation like [https-proxy-agent][] or
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[socks-proxy-agent][].
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## Changelog
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We're using the GitHub [releases][changelog] for changelog entries.
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## License
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[MIT](LICENSE)
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[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
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[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
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[client-report]: http://websockets.github.io/ws/autobahn/clients/
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[server-report]: http://websockets.github.io/ws/autobahn/servers/
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[permessage-deflate]: https://tools.ietf.org/html/rfc7692
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[changelog]: https://github.com/websockets/ws/releases
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