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javascriptxulxulrunner

How to know if the network is (dis)connected?

How can I know, in Xul, if the network is (dis)connected?

--update

Using:

    function observe(aSubject, aTopic, aState) {
        if (aTopic == "network:offline-status-changed") {
            write("STATUS CHANGED!");
        }
    }
    var os = Components.classes["@mozilla.org/observer-service;1"].getService(Components.interfaces.nsIObserverService);
    os.addObserver(observe, "network:offline-status-changed", false);

and the preference:

pref("network.manage-offline-status", true);

it's not working.. There's a bug report here, but I don't think it has something to do with it.

--

Actually I think it's not possible to be notified, as even in Firefox we're never notified, and the user need to manually mark "work offline" if he wants the browser to know that it's offline..

--

Screenshot my of Firefox "about:config" filtering for "offline" string, unfortunately, there no "network.manage-offline-status":

enter image description here

Solution

  • The best way I found is to use the following javascript code, that behaves like a ping, and make the test with some big websites, and assume that if none of them answers, so the network must be disconnected.

    var ping = {};
ping = {
    img:null,
    imgPreload:null,
    timer:null,
    init:function() {
        var sess = new Date();
        var nocache = sess.getTime();
        var imguri = ping.img+"?time="+nocache;
        var ping.imgPreload = new Image();
        ping.imgPreload.onload = function() {
            clearTimeout(ping.timer);
            ping.timer = null;
            alert("Domain is available");
        };
        ping.imgPreload.src = imguri;
        ping.timer = setTimeout("ping.fail_to_ping()",60000);
    },
    fail_to_ping:function() {
        clearTimeout(ping.timer);
        ping.timer = null;
        ping.imgPreload = null;
        alert("Ping to domain failed!");
    }
};

    (from http://crynobone.com/ci/index.php/archive/view/852)

    --update

    But, as it's not a reliable solution (as you can't rely that the image will be in the website forever), the best solution might be to develop a new XPCom component.