xhr-shaper

xhr-shaper

https://tchakabam.github.io/xhr-shaper/

Shapes your XHR requests to a max emulated bandwidth and latency, randomizes frequency of progress events

Blog post: http://dispar.at/blog/2017/06/09/xhr-shaper/

Install:

npm install xhr-shaper

How to use:

As global/window shim

require('xhr-shaper').useGlobal();

// now XMLHttpRequest object is the shim

NOTE: Running useGlobal will overload the XHR constructor in the window to produce a mirror object which will have the exact same behavior, but it's not an instance of the native XMLHttpRequest (in case that matters for some reason to you). The mirror XHR has an additional property called shaper ...

Or in a modular way

var XHRShaper = require('xhr-shaper');

var xhr = new XHRShaper.XMLHttpRequest(); 

NOTE: XHRShaper module exposes some fancy undocumented stuff like BaseXHR and objectMirrors. These might be moved into their own package in the future.

var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function(e) {
  console.log('readyState: ' + xhr.readyState);
};
xhr.onprogress = function(e) {
  console.log('Progress: ' + e.loaded + ' of ' + e.total);
};
xhr.withCredentials = false;
xhr.open('GET', "http://www.streambox.fr/playlists/test_001/stream_110k_48k_416x234_000.ts", true);
xhr.responseType = 'arraybuffer';

Create a bare XHR just as always ...

// Set your minimum desired latency !
xhr.shaper.minLatency = 1000;

// Set your maximum desired bandwidth
xhr.shaper.maxBandwidth = 512;

Or make these things global so they will apply on ALL requests!!!

// all requests will be limited to 64kbps and take at least 5000 ms
XMLHttpRequest.Shaper.maxBandwidth = 64;
XMLHttpRequest.Shaper.minLatency = 5000;

... wait for things to happen.

xhr.send();

Test/dev:

Run npm run dev

Now go to http://localhost:8080/webpack-dev-server/

Automated BDD testsuite using Mocha.js

go to http://localhost:8080/webpack-dev-server/tests.html

TODOs:

• randomizing feature
• proper automated tests
• implement all handlers as in https://xhr.spec.whatwg.org/

interface XMLHttpRequestEventTarget : EventTarget { // event handlers attribute EventHandler onloadstart; attribute EventHandler onprogress; attribute EventHandler onabort; attribute EventHandler onerror; attribute EventHandler onload; attribute EventHandler ontimeout; attribute EventHandler onloadend; };