http range request filter

[caspereg]

i found a firefox addon that helps bypassing the download limitation

https://addons.mozilla.org/en-us/firefox...unlimited/
the open source for the addon
https://github.com/rumal/Download-Unlimited

this firefox addon modify the http Header Request
it modify the range to the allowed range
by this function

PHP Code:

// if the range header is set by the downloadThemAll
var range = httpChannel.getRequestHeader('Range');
lowRange = range.substring(6,range.length-1);
var upRange = parseInt(lowRange) + download_unlimited.step;
//change it to the allowed range
httpChannel.setRequestHeader('Range','bytes='+lowRange+'-'+upRange,false);
range = httpChannel.getRequestHeader('Range'); 


https://github.com/rumal/Download-Unlimi...overlay.js
who can i make a filter that do the same job of this addon