Angular - update services object during asynchronous function - angularjs

Question

Folks: Creating an app in angular and node webkit - where users queue up files for downloading, navigate to their dashboard view and this initiates the downloads.
I've created a service which holds an object of the files data:
..
var downloadObj = {};
// fileObj = {'name':'The file name'; 'download_progress' : dlProgress}
showcaseFactory.myDownloads = function(eventId, fileObj) {
if(eventId){
console.log('update the object');
downloadObj['event_'+eventId] = fileObj;
}
console.log(downloadObj);
};
showcaseFactory.getDownloads = function() {
return downloadObj;
};
..
When the dashboard view loads - ng-repeat loops over $scope.downloadFiles which references this object returning the data.
<div ng-repeat="file in downloadFiles">
<div><span>{{file.name}}</span> [{{file.download_progress}}%]</div>
</div>
I've created a custom module which utilises node_modules to perform the download of the files:
nwjsDownloadFactory.commenceDownload = function(event_id, url, dest, cb) {
var http = require('http');
var fs = require('fs');
var statusBar = require('status-bar');
var path = require('path');
// THIS UPDATES THE OBJECT AND DISPLAYS FINE --------- >>
var id = 7;
var testFileObj = {
'name' : 'This is the file name prior to the download...',
'download_progress' : 10
};
ShowCase.myDownloads(id, testFileObj);
// <<< THIS UPDATES THE OBJECT AND DISPLAYS FINE ---------
var file = fs.createWriteStream(dest);
var request = http.get(url, function(response) {
response.pipe(file);
file.on('finish', function() {
file.close(cb); // close() is async, call cb after close completes.
});
bar = statusBar.create({ total: response.headers['content-length'] })
.on('render', function (stats) {
// var percentage = this.format.percentage(stats.percentage);
// console.log(event_id + '....' + percentage);
var id = 7;
var testFileObj = {
'name' : 'This is the new file name during the download...',
'download_progress' : 35 // this will be replaced with percentage
};
ShowCase.myDownloads(id, testFileObj);
});
response.pipe(bar);
}).on('error', function(err) { // Handle errors
fs.unlink(dest); // Delete the file async. (But we don't check the result)
if (cb) cb(err.message);
});
}
QUESTION: Prior to the line var request = http.get(url, function(response) the object gets updated, and the changes are reflected in the UI. However, I need to constantly update the object with download complete % so I can create a progress bar.. However, as this asynchronous function executes, the object
appears to be updating - see the attached screen shot - but the UI is not reflecting this.
Can somebody please steer me in the right direction - I need the object to update during the function bar = statusBar.create({ and for the changes to reflect in the UI..

Answer 1

Call $scope.$apply() after making changes to your model to notify Angular that it has to update the UI.
showcaseFactory.myDownloads = function(eventId, fileObj) {
if(eventId){
console.log('update the object');
downloadObj['event_'+eventId] = fileObj;
$scope.$apply();
}
console.log(downloadObj);
};
If you use Angular's $http object, this is handled automatically for you, but if you update your model from other asynchronous callbacks, you have to take care of it yourself.
See this blog post and this documentation page for more in-depth explanations about what's going on.