Use HTML5 websockets using the Node Streams API.
This module works in Node or in Browsers that support WebSockets. You can use browserify to package this module for browser use.
var websocket = require('websocket-stream')
var ws = websocket('ws://echo.websocket.org')
process.stdin.pipe(ws)
ws.pipe(process.stdout)
In the example above ws
is a duplex stream. That means you can pipe output to anything that accepts streams. You can also pipe data into streams (such as a webcam feed or audio data).
The underlying WebSocket
instance is available as ws.socket
.
The available options differs depending on if you use this module in the browser or with node.js. Options can be passed in as the third or second argument - WebSocket(address, [protocols], [options])
.
How much to allow the socket.bufferedAmount to grow before starting to throttle writes. This option has no effect in node.js.
Default: 1024 * 512
(512KiB)
How long to wait before checking if the socket buffer has drained sufficently for another write. This option has no effect in node.js.
Default: 1000
(1 second)
Send each chunk on its own, and do not try to pack them in a single websocket frame.
Default: false
Always convert to Buffer
in Node.js before sending.
Forces options.objectMode
to false
.
Default: true
We recommend disabling the per message deflate extension to achieve the best throughput.
Default: true
on the client, false
on the server.
Example:
var websocket = require('websocket-stream')
var ws = websocket('ws://realtimecats.com', {
perMessageDeflate: false
})
Beware that this option is ignored by browser clients. To make sure that permessage-deflate is never used, disable it on the server.
When used in node.js see the ws.WebSocket documentation
Using the ws
module you can make a websocket server and use this module to get websocket streams on the server:
var websocket = require('websocket-stream')
var wss = websocket.createServer({server: someHTTPServer}, handle)
function handle(stream, request) {
// `request` is the upgrade request sent by the client.
fs.createReadStream('bigdata.json').pipe(stream)
}
We recommend disabling the per message deflate extension to achieve the best throughput:
var websocket = require('websocket-stream')
var wss = websocket.createServer({
perMessageDeflate: false,
server: someHTTPServer
}, handle)
function handle(stream) {
fs.createReadStream('bigdata.json').pipe(stream)
}
You can even use it on express.js with the express-ws library:
const express = require('express');
const expressWebSocket = require('express-ws');
const websocketStream = require('websocket-stream/stream');
const app = express();
// extend express app with app.ws()
expressWebSocket(app, null, {
// ws options here
perMessageDeflate: false,
});
app.ws('/bigdata.json', function(ws, req) {
// convert ws instance to stream
const stream = websocketStream(ws, {
// websocket-stream options here
binary: true,
});
fs.createReadStream('bigdata.json').pipe(stream);
});
app.listen(3000);
Errors both from the underlying websocket and from the TCP socket itself are propagated and emitted on the stream so you must provide an error handler for the stream even if you already have an error handler on the websocket, e.g:
var websocket = require('websocket-stream')
var wss = websocket.createServer({server: someHTTPServer}, handle)
// this is not enough!
someHTTPServer.on('connection', function(socket) {
socket.on('error', function(err) {
console.log("Client socket error:", err);
});
});
function handle(stream, request) {
// we need this as well
stream.on('error', function(err) {
console.log("Stream error:", err);
});
}
If you neglect to add the stream error handler then a simple ECONNRESET
will crash your application.
npm test
First start the echo server by running node test-server.js
Then run npm start
and open localhost:9966
in your browser and open the Dev Tools console to see test output.
BSD LICENSE