firefox addon page-mod - when url doesn't match - firefox

Question

I want to be able to activate a widget if a url matches some pattern, but the problem is I also want to disable the widget when page-mod rule doesn't match the url.
So if I have few tabs open and if I switch between them I should be able to somehow disable the widget if an active tab's url doesn't match the rule, or in other case activate it. The state of widget(on/off) should be changed on loading pages and switching through tabs.
I've been struggling with this for a while and still haven't found a solution.
This is where I'm at right now:
// Activates on matching one of the site domains, but I also want to deactivate
// it when it does not match
var pageMod = require("page-mod");
pageMod.PageMod({
include: ["*.site1.com","*.site2.com"],
onAttach: function() {
alert("Widget activated!");
});
});
Thank you for any help!

Answer 1

If I understand correctly what you are trying to do then page-mod is the wrong solution - you simply want to listen to the active tab. Use tabs module for that, listen to ready (new URL loaded) and activate (active tab changed) events:
var tabs = require("tabs");
tabs.on("ready", function(tab)
{
if (tab == tabs.activeTab)
updateActiveTab(tab);
});
tabs.on("activate", function(tab)
{
updateActiveTab(tab);
});
Your updateActiveTab() function would need to check tab.url and activate or deactivate the widget then. If you want to use patterns for that like the ones you specify for page-mod then you need to use the internal match-pattern module, like this:
var {MatchPattern} = require("match-pattern");
var patterns = [
new MatchPattern("*.site1.com"),
new MatchPattern("*.site2.com")
];
function updateActiveTab(tab)
{
var matches = false;
for (var i = 0; i < patterns.length; i++)
if (patterns[i].test(tab.url))
matches = true;
if (matches)
activateWidget();
else
deactivateWidget();
}
But of course you can just use a regular expression or something like this to test tab.url, you don't have to use the match-pattern module.
Disclaimer: The code examples are only there to make the approach easier to understand, they haven't been tested.