Firefox Add-On to redirect urls based on wildcards

Question

I am looking at writing a firefox extension which will take a url, apply a regex to it to produce a second url. I then need to have firefox redirect to this new URL without the user having to do anyything.

Does anyone have any examples I could use to learn how to do this. I've used the firefox tutorials to get as far as this..

// Import the page-mod API
var pageMod = require("sdk/page-mod");
// Import the self API
var self = require("sdk/self");

// Create a page mod
// It will run a script whenever a ".org" URL is loaded
// The script replaces the page contents with a message
pageMod.PageMod({
  include: "*",
  contentScript: 'window.alert("Matched Page");'
})

So my question is, how would I do this. For instance, if a user types in http://www.mywebsite/data/7287232/wherever, I'd like them to be redirected to http://www.anotherwebsite/folder/7287232

Answer 1

Well.. answering to the initial head line:

https://addons.mozilla.org/en-US/firefox/addon/redirector

Or is that actually you? @ScaryAardvark ?

Answer 2

that example is very complex, the main purpose of that traceable channel example is to get a COPY of the sourcecode that gets loaded at that uri.

const { Ci, Cu, Cc, Cr } = require('chrome'); //const {interfaces: Ci, utils: Cu, classes: Cc, results: Cr } = Components;
Cu.import('resource://gre/modules/Services.jsm');
Cu.import('resource://gre/modules/devtools/Console.jsm');

var observers = {
    'http-on-modify-request': {
        observe: function (aSubject, aTopic, aData) {
            console.info('http-on-modify-request: aSubject = ' + aSubject + ' | aTopic = ' + aTopic + ' | aData = ' + aData);
            var httpChannel = aSubject.QueryInterface(Ci.nsIHttpChannel);
            var requestUrl = httpChannel.URI.spec
            if (/\.org/.test(requestUrl) || /http\:\/\/www\.mywebsite\/data\/7287232\/.+/.test(requestUrl)) {
                httpChannel.redirectTo(Services.io.newURI('http://www.anotherwebsite/folder/7287232', null, null));
            }
        },
        reg: function () {
            Services.obs.addObserver(observers['http-on-modify-request'], 'http-on-modify-request', false);
        },
        unreg: function () {
            Services.obs.removeObserver(observers['http-on-modify-request'], 'http-on-modify-request');
        }
    }
};

to register the observer on startup of addon run this:

//register all observers
for (var o in observers) {
    observers[o].reg();
}

and on shutdown of addon unregister all observers like this:

//unregister all observers
for (var o in observers) {
    observers[o].unreg();
}