Test SDK extension for Downloads.jsm See: http://stackoverflow.com/questions/18195513/firefox-addon-downloads-jsm

main.js

const {Cc, Ci, Cu} = require("chrome");
const {notify} = require("sdk/notifications");
const {Widget} = require("sdk/widget");

const {Downloads} = Cu.import("resource://gre/modules/Downloads.jsm", {});
const {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});

function download() {
  Task.spawn(function() {
    var options = {
      source: "http://cdn.sstatic.net",
      target: "/tmp/kaki.html",
    };
    // Firefox pre Aurora-25 did implement an "old" API version, which required
    // a different set of options.
    // See: http://mzl.la/1cwWZ2N
    if (Services.vc.compare(Services.appinfo.version, "25.0a") < 0) {
      var file = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
      file.initWithPath(options.target);
      options = {
        source: {uri: Services.io.newURI(options.source, null, null)},
        target: {file: file},
        saver: {type: "copy"},
      };
    }

    var d = yield Downloads.createDownload(options);
    var res = d.whenSucceeded();
    // lets start the download ...
    yield d.start();
    // ... and wait for it to finish
    yield res;

    notify({
      title: "Test-Extension",
      text: "Download finished",
      onClick: function (data) {
        if ('showContainingDirectory' in d) {
          d.showContainingDirectory();
        }
      }
    });
  }).then(null, function(ex) {
    Cu.reportError(ex);
    notify({
      title: "Test-Extension",
      text: "Error: " + ex
    });
  });
}

Widget({
    id: "test-downloads",
    label: "Start a test download",
    contentURL: "https://tn123.org/favicon.ico",
    onClick: download
});