https://github.com/sockjs/websocket-multiplex

A thin library for doing multiplexing on top of SockJS
https://github.com/sockjs/websocket-multiplex

Last synced: 4 days ago
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A thin library for doing multiplexing on top of SockJS

• Host: GitHub
• URL: https://github.com/sockjs/websocket-multiplex
• Owner: sockjs
• License: mit
• Created: 2012-03-16T13:47:41.000Z (almost 13 years ago)
• Default Branch: master
• Last Pushed: 2021-06-08T10:54:02.000Z (over 3 years ago)
• Last Synced: 2024-04-15T14:09:04.127Z (9 months ago)
• Language: JavaScript
• Homepage: https://github.com/sockjs/websocket-multiplex
• Size: 14.6 KB
• Stars: 160
• Watchers: 10
• Forks: 37
• Open Issues: 12
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
WebSocket-multiplex

===================

WebSocket-multiplex is a small library on top of SockJS that allows

you to do multiplexing over a single SockJS connection.

The rationale for that is explained in details in the following blog

post:

  * https://www.rabbitmq.com/blog/2012/02/23/how-to-compose-apps-using-websockets/

Usage from the browser

----------------------

On the client side (browser) load library like that:

    

      

Alternatively, if you're using SSL:

    

      

Usage example:

```javascript

    var sockjs_url = '/multiplex';

    var sockjs = new SockJS(sockjs_url);

    var multiplexer = new WebSocketMultiplex(sockjs);

    var ann  = multiplexer.channel('ann');

    var bob  = multiplexer.channel('bob');

    var carl = multiplexer.channel('carl');

```

Usage from the node.js server

-----------------------------

On the node.js server side, you can use npm to get the code:

    npm install websocket-multiplex

And a simplistic example:

```javascript

    var multiplex_server = require('websocket-multiplex');

    // 1. Setup SockJS server

    var service = sockjs.createServer();

    // 2. Setup multiplexing

    var multiplexer = new multiplex_server.MultiplexServer(service);

    var ann = multiplexer.registerChannel('ann');

    ann.on('connection', function(conn) {

        conn.write('Ann says hi!');

        conn.on('data', function(data) {

            conn.write('Ann nods: ' + data);

        });

    });

    // 3. Setup http server

    var server = http.createServer();

    sockjs_echo.installHandlers(server, {prefix:'/multiplex'});

    var app = express.createServer();

```

For a full-featured example see the

[/examples/sockjs](https://github.com/sockjs/websocket-multiplex/tree/master/examples/sockjs)

directory.

Protocol

--------

The underlying protocol is quite simple. Each message is a string consisting of

three comma separated parts: _type_, _topic_ and _payload_. There are

three valid message types:

 * `sub` - expresses a will to subscribe to a given _topic_.

 * `msg` - a message with _payload_ is being sent on a _topic_.

 * `uns` - a will to unsubscribe from a _topic_.

Invalid messages like wrong unsubscriptions or publishes to a _topic_

to which a client was not subscribed to are simply ignored.

This protocol assumes that both parties are generally willing to

cooperate and that no party makes errors. All invalid

messages should be ignored.

It's important to notice that the namespace is shared between both

parties. It is not a good idea to use the same topic names on the

client and on the server side because both parties may unsubscribe

the other from a topic.