IOTConnect-Web/node_modules/websocket-stream/readme.md
2024-05-09 09:49:52 +08:00

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# websocket-stream
[![NPM](https://nodei.co/npm/websocket-stream.png?global=true)](https://nodei.co/npm/websocket-stream/)
Use HTML5 [websockets](https://developer.mozilla.org/en-US/docs/WebSockets) using the Node Streams API.
### Usage
This module works in Node or in Browsers that support WebSockets. You can use [browserify](http://github.com/substack/node-browserify) to package this module for browser use.
```javascript
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`.
#### Options
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])`.
##### `options.browserBufferSize`
How much to allow the [socket.bufferedAmount](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket#Attributes) to grow before starting to throttle writes. This option has no effect in node.js.
Default: `1024 * 512` (512KiB)
##### `options.browserBufferTimeout`
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)
##### `options.objectMode`
Send each chunk on its own, and do not try to pack them in a single
websocket frame.
Default: `false`
##### `options.binary`
Always convert to `Buffer` in Node.js before sending.
Forces `options.objectMode` to `false`.
Default: `true`
##### `options.perMessageDeflate`
We recommend disabling the [per message deflate
extension](https://tools.ietf.org/html/rfc7692) to achieve the best
throughput.
Default: `true` on the client, `false` on the server.
Example:
```js
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.
##### Other options
When used in node.js see the [ws.WebSocket documentation](https://github.com/websockets/ws/blob/master/doc/ws.md#class-wswebsocket)
### On the server
Using the [`ws`](http://npmjs.org/ws) module you can make a websocket server and use this module to get websocket streams on the server:
```javascript
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](https://tools.ietf.org/html/rfc7692) to achieve the best
throughput:
```javascript
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](https://www.npmjs.com/package/express-ws) library:
```js
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);
```
## Run the tests
### Server-side tests
```
npm test
```
### Client-side tests
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.
## license
BSD LICENSE