Firefox add-on pageMod, catch ajax done in contentScriptFile

Question

my problem is that i need to know when AJAX is done on the page. I need to know this in my contentScriptFile that i load through pageMod. My add on needs to run every time that the page has been modified: so basically when it loads and every time there is an AJAX call.

i tried this:

$(document).ajaxComplete(function() {
     alert("AJAX call completed");
});

but it does not work.

is there a way to do this?

edit: my page mod code from main.js:

pageMod.PageMod({
     include: "*",
     contentScriptFile: [self.data.url("jquery-1.9.1.min.js"), 
     self.data.url("script.js")],

     onAttach: function(worker){

      var apiKey = require("sdk/simple-prefs").prefs.apiKey;
      var ignoreList = require("sdk/simple-prefs").prefs.ignoreList;

      worker.port.emit("prefSet", [ignoreList, apiKey]);

      }

});

Answer 1

Put this not in a content script: Im not sure how you will identify the content window of the script. I dont know sdk so well. But see the area CONTENT_WINDOW_OF_CONTENT_SCRIPT

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
            var goodies = loadContextAndGoodies(aSubject, true);
            if (goodies.contentWindow) {
               if (goodies.contentWindow == CONTENT_WINDOW_OF_CONTENT_SCRIPT) {
                    //do something here
               }
            }
        },
        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');
        }
    }
};

Then in that same scope add in this helper function:

function loadContextAndGoodies(request, return_goodies) {
  var loadContext = null;

  if (request instanceof Ci.nsIRequest) {
      try {
          if (request.loadGroup && request.loadGroup.notificationCallbacks) {
              loadContext = request.loadGroup.notificationCallbacks.getInterface(Ci.nsILoadContext);
          }
      } catch (ex) {
        console.exception('request loadGroup with notificationCallbacks but oculd not get nsIloadContext', ex);
      }
      if (!loadContext) {
        try {
            if (request.notificationCallbacks) {
                loadContext = request.notificationCallbacks.getInterface(Ci.nsILoadContext);
            }
        } catch (ex) {
          console.exception('request has notificationCallbacks but could not get nsILoadContext', ex);
          /* start - noit's backup try, it might be redundant (im not sure) as Wladamir Palant didn't have this way*/
          try {
            var interfaceRequestor = httpChannel.notificationCallbacks.QueryInterface(Ci.nsIInterfaceRequestor);
            loadContext = interfaceRequestor.getInterface(Ci.nsILoadContext);
          } catch (ex) {
            console.exception('backup method failed:' ex);
          }
          /* end - my backup try, it might be redundant as Wladamir Palant didn't have this way*/
        }
      }
  } else {
    console.warn('request argument is not instance of nsIRequest')
  }

  if (return_goodies) {
    if (!loadContext) {
      return null;
    }

    var contentWindow = loadContext.associatedWindow;
    var DOMWindow = contentWindow.top.QueryInterface(Ci.nsIInterfaceRequestor)
                                     .getInterface(Ci.nsIWebNavigation)
                                     .QueryInterface(Ci.nsIDocShellTreeItem)
                                     .rootTreeItem
                                     .QueryInterface(Ci.nsIInterfaceRequestor)
                                     .getInterface(Ci.nsIDOMWindow);
    var gBrowser = DOMWindow.gBrowser;
    if (gBrowser) {
      var tab = gBrowser._getTabForContentWindow(contentWindow.top);
      var browser = tab.linkedBrowser;
    } else {
      var tab, browser = null;
    }
    var goodies = {
      loadContext: loadContext,
      DOMWindow: DOMWindow,
      gBrowser: gBrowser,
      contentWindow: contentWindow,
      browser: browser,
      tab: tab
    };

    return goodies;
  } else {
    return loadContext;
  }
}

To start observing

To start start obseving all requests do this (for example on startup of your addon)

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

To stop observing

Its important to stop observring (make sure to run this at least on shutdown of addon, you dont want to leave the observer registered for memory reasons)

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