Detect tab URL change inside a Firefox add-on

Question

I have an extension, functional on Chrome, that monitors the active Tab for URL changes.

Specifically, I need to detect when the URL changes, but there is no new page load or navigation. Some sites do this (e.g. when you click to view another video on YouTube).

On Chrome, I accomplished this with:

chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
    if (changeInfo && changeInfo.status == "complete") {
        //do stuff here
    }
});

How do I detect such changes in a Firefox add-on?

I've been told to use: Listening to events on all tabs, but I couldn't put it together. One of the problems was that gBrowser was not defined in the extension.

What am I doing wrong?

Is there a simpler way?

Answer 1

Use ProgressListener to be notified about location changes.

To install a listener, convert SDK tab to its raw (old) representation using viewFor. Backward conversion is possible with modelFor and getTabForContentWindow.

const tabs = require("sdk/tabs");
const {viewFor} = require('sdk/view/core');
const {modelFor} = require('sdk/model/core');
const {getBrowserForTab, getTabForContentWindow} = require("sdk/tabs/utils");
const {Ci, Cu} = require("chrome");
Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);

var progressListener = {
QueryInterface: XPCOMUtils.generateQI([Ci.nsIWebProgressListener, Ci.nsISupportsWeakReference]),
    onLocationChange: function(aProgress, aRequest, aURI) {
        var highLevel= modelFor(getTabForContentWindow(aProgress.DOMWindow));
        console.log("onLocationChange ", highLevel.url);
    }
};

tabs.on('open', function(newTab) {
    var lowLevel = viewFor(newTab);
    var browser = getBrowserForTab(lowLevel);
    browser.addProgressListener(progressListener);
});

Don't forget to remove listeners on extension unload. Tab listeners are removed automagically, but ProgressListeners won't be.

Inspired by Converting to chrome windows