rtc-switchboard

This is an rtc.io signalling server (counterpart to rtc-signaller) that makes use of the excellent realtime abstraction library, primus. It has been designed and built primarily as a reference implementation for a signalling server and is not designed to be deployed at scale.

Try it out

If you would like to our test signalling server (no uptime guaranteed) then you can use rtc-quickconnect and take it for a spin:

var quickconnect = require('rtc-quickconnect');

quickconnect('//switchboard.rtc.io/', { room: 'switchboard-test' })
  .createDataChannel('test')
  .once('channel:opened:test', function(peerId, dc) {
    dc.onmessage = function(evt) {
      console.log('received data: ', evt.data);
    };

    dc.send('hello');
  });

Other examples are available in the guidebook

Usage: Standalone

If you wish to use rtc-switchboard on it's own to test signalling, then you can simply clone this repository, install dependencies and start the server:

git clone https://github.com/rtc-io/rtc-switchboard.git
cd rtc-switchboard
npm install
node server.js

If you wish to run the server on a specific port, then set the NODE_PORT environment variable prior to execution:

NODE_PORT=8997 node server.js

Usage: API

To create an application using primus signalling, see the following examples:

Pure Node HTTP

var server = require('http').createServer();
var switchboard = require('./')(server, { servelib: true });
var port = parseInt(process.env.NODE_PORT || process.env.PORT || process.argv[2], 10) || 3000;
var replify = require('replify');

server.on('request', function(req, res) {
  if (req.url === '/') {
    res.writeHead(302, {
      'Location': 'https://github.com/rtc-io/rtc-switchboard'
    });
    res.end('switchboard available from: https://github.com/rtc-io/rtc-switchboard');
  }
});

// start the server
server.listen(port, function(err) {
  if (err) {
    return console.log('Encountered error starting server: ', err);
  }

  console.log('server running at http://localhost:' + port + '/');
});

// add the repl
replify({
  name: 'switchboard',
  app: switchboard,
  contexts: {
    server: server
  }
});

switchboard.on('room:create', function(room) {
  console.log('room ' + room + ' created, now have ' + switchboard.rooms.length + ' active rooms');
});

switchboard.on('room:destroy', function(room) {
  console.log('room ' + room + ' destroyed, ' + switchboard.rooms.length + ' active rooms remain');

  if (typeof gc == 'function') {
    console.log('gc');
    gc();
  }
});

Using Express

var express = require('express');
var app = express();
var server = require('http').Server(app);
var port = process.env.PORT || 3000;

// create the switchboard
var switchboard = require('rtc-switchboard')(server);

// we need to expose the primus library
app.get('/rtc.io/primus.js', switchboard.library());

server.listen(port, function(err) {
  if (err) {
    return;
  }

  console.log('server listening on port: ' + port);
});

Including the Primus Client

The rtc-switchboard makes use of the slick WebSockets abstraction library Primus. To work with the server, you will need to include the primus.js library in your application prior to attempting a websocket connection.

If you are working with a local standalone server, the following script tag will likely do the job:

<script src="http://localhost:3000/rtc.io/primus.js"></script>

NOTE: A specific call to include primus is not required if you are working with particular rtc.io library (such as rtc-glue), as they will ensure the primus library has been included prior to running their internal code.

Usage: Docker

If you are interested in deploying an instance of rtc-switchboard using docker then the following is a great place to start:

https://github.com/synctree/docker-rtc-switchboard

Writing Custom Command Handlers

When you initialize the switchboard, you are able to provide custom handlers for specific commands that you want handled by the switchboard. Imagine for instance, that we want our switchboard to do something clever when a client sends an /img command.

We would create our server to include the custom img command handler:

var server = require('http').createServer();
var Primus = require('primus');

// create the signaller, providing our own primus instance (using engine.io)
var switchboard = require('rtc-switchboard')(server, {
  servelib: true,
  handlers: {
    img: require('./handlers/img')
  }
});

// start the server
server.listen(3000);

And then we would write a small module for the handler:

module.exports = function(mgr, spark, data, payload) {
  console.log('received an img command with payload: ', payload);
};

Logging and Analytics using the data event

Every message that flows through the switchboard (whether handled or not) can be logged through tapping into the data event. The example below demonstrates how this can be done with a node logging module like bunyan:

var express = require('express');
var app = express();
var server = require('http').Server(app);
var port = process.env.PORT || 3000;
var bunyan = require('bunyan');
var log = bunyan.createLogger({ name: 'rtc-switchboard' });

// create the switchboard
var switchboard = require('rtc-switchboard')(server);

// we need to expose the primus library
app.get('/rtc.io/primus.js', switchboard.library());

server.listen(port, function(err) {
  if (err) {
    return;
  }

  console.log('server running at: http://localhost:' + port + '/');
});

switchboard.on('data', function(data, peerId, spark) {
  log.info({ peer: peerId }, 'received: ' + data);
});

As can be seen in the example above, the handlers of the data event can expect to receive three arguments to the handler function, as per the code snippet below:

switchboard.on('data', function(data, peerId, spark) {
});

The data is the raw data of that has been sent from the client, the peerId is the id of the peer sending the data (this will be undefined if it is a message received prior to an /announce command). Finally we have the raw primus spark that can be examined for additional information.

Reference

switchboard(server, opts?)

Create the switchboard which uses primus under the hood. By default calling this function will create a new Primus instance and use the pure websockets adapter.

Custom Message Handlers

The socket server is configured to handle some specific rtc.io signaller messages. The handlers are stored in the handlers/ folder of the repository and have details outlined below.

announce handler

Will handle /announce messages and associate the peer id assigned by the client-side signaller with the socket on the server side.

This will allow routing of messages to the correct receipient when /to messages are received.

ping handler

Will handle /ping messages

License(s)

Apache 2.0

Copyright 2014 National ICT Australia Limited (NICTA)

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.