BwCh

BwCh is an open-source JavaScript API to detect bandwidth for web-based environments. It uses some of the latest JavaScript innovation (window.navigator.connection currently supported in Chrome 48+ for Android as of April 2016) in order to provide a flexible method to detect bandwidth for both mobile and desktop devices. It fallbacks to image pre-loading to detect bandwidth where those newest API are not available.

BwCh is used for some of Radiant Media Player newest features.

BwCh is written with ES2015. It is compiled to classic ES5 JavaScript with Babel and Browserify. The main file consist of an ES2015 class that needs to be imported in a project where it can be used.

A complete implementation example and jasmine-based test suite are provided.

You can see it live at work here.

Contributions are welcome.

Usage

Import BwCh class from bwch.js, create a new instance and call the getBandwidth method. A Promise is returned resolving to the detected bandwidth.

import 'babel-polyfill';
import {BwCh} from '../../../src/bwch';
(() => {
  'use strict';
  const bwch = new BwCh('https://cdn.radiantmediatechs.com/rmp/bandwidth', 4, 2000, true, true);
  let bw = bwch.getBandwidth(); 
  bw.then((bandwidth) => {
    console.log(bandwidth);
  });
})();  

The bandwidth returned value is a Number representing the detected bandwidth in kbps. If the bandwidth could not be determined (no Internet connection or errors while processing the detection) -1 is returned.

Params for the BwCh constructor

new BwCh(imagesLoc, steps, timeout, randomQS, debug);

imagesLoc is a String which represents the location of your test images. Default: '../img/'. Please do not use the https://cdn.radiantmediatechs.com/rmp/bandwidth base URL in your project as this is just a demo. Host the images on your server. Images are PNG because it is an uncompressed format best suited for testing download speed.

steps is the Number of steps for bandwidth detection. Valid values are 1, 2, 3 or 4. The more steps the better is the bandwidth detection but at the cost of extra processing.

timeout is a Number in ms representing the time after which the image preloading (for each image) is stopped. Default 2000.

randomQS is a Boolean. When true it adds a random query string to the image preloading URLs. Default true.

debug is a Boolean. When true it logs BwCh data to the browser console.

Building

git clone https://github.com/radiantmediaplayer/bwch.git
cd bwch
npm install
grunt

You can use grunt dev for watchify tasks. You need to have jshint, browserify and watchify installed globally to make it work!

Test must be done in a real browser with Jasmine for best results.

License

MIT as outlined in the license.txt file