pull-datachannel

Pull Stream interfaces for working with WebRTC data channels.

Example Usage

Displayed below is an example that demonstrates how pull-streams can be used in conjunction with the data channel to transmit and receive data via data-channels:

var qc = require('rtc-quickconnect');
var pull = require('pull-stream');
var observable = require('pull-observable');
var dc = require('pull-datachannel');

// create a canvas to draw the remote line
var canvas = document.createElement('canvas');
var context = canvas.getContext('2d');

// initialise the canvas height and width and add to the doc
canvas.width = 640;
canvas.height = 480;
document.body.appendChild(canvas);

// capture the pointer on the document
var point = require('point')(canvas);

function drawCursor(color) {
  var lastXY = [];

  return function(args) {
    var xy = args.slice(0, 2);
    var data = args[2];

    if (data.type === 'move') {
      context.strokeStyle = color;
      context.beginPath();
      context.moveTo.apply(context, lastXY);
      context.lineTo.apply(context, xy);
      context.stroke();
      context.closePath();
    }

    // save the last xy
    lastXY = [].concat(xy);

    return args.slice(0, 3);
  };
}

qc('https://switchboard.rtc.io/', { room: 'pulldc-sharedpointer' })
  .createDataChannel('cursor')
  .on('channel:opened:cursor', function(peerId, channel) {
    console.log('data channel opened for peer: ' + peerId);

    // stream the pointer information across the datachannel
    pull(
      observable(point),
      pull.map(drawCursor('#000')),
      pull.map(JSON.stringify),
      dc.write(channel)
    );

    // read incoming pointer information
    pull(
      dc.read(channel),
      pull.map(JSON.parse),
      pull.drain(drawCursor('#F00'))
    );
  });

NOTE: At this stage, even though I'm sending only text data I am still seeing data-channel exceptions in chrome. I have implemented a short term try / catch block to work around the issue in the short term...

Also if you aren't seeing events across the connection, it's important to note that point is a simple library that captures unified pointer events (mouse and touch) so you will need to click and drag the mouse to create move events.

Reference

read

Create a pull-stream source on a RTCDataChannel.

var qc = require('rtc-quickconnect');
var pull = require('pull-stream');
var randomName = require('random-name');
var dc = require('pull-datachannel');

qc('https://switchboard.rtc.io/', { room: 'pull-dc-read' })
  .createDataChannel('test')
  .on('channel:opened:test', function(peerId, channel) {
    console.log('data channel opened for peer: ' + peerId);

    // when we get data, log it
    pull(
      dc.read(channel),
      pull.log()
    );

    sendRandomNames(channel);
  });

function sendRandomNames(channel) {
  setTimeout(function() {
    channel.send(randomName());
    sendRandomNames(channel);
  }, Math.random() * 1000);
}

write

Create a pull-stream sink on target data channel.

var qc = require('rtc-quickconnect');
var pull = require('pull-stream');
var dc = require('pull-datachannel');

qc('https://switchboard.rtc.io/', { room: 'pulldc-write' })
  .createDataChannel('test')
  .on('channel:opened:test', function(peerId, channel) {
    console.log('data channel opened for peer: ' + peerId);

    channel.addEventListener('message', function(evt) {
      console.log('received data: ', evt.data);
    });

    // send some data to the channel
    pull(
      pull.values([1, 2, 3, 4]),
      dc.write(channel)
    );
  });

License(s)

MIT

Copyright (c) 2015 Damon Oehlman [email protected]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.