Offload API request from controller to service - angularjs

Question

I offloaded the call to the Twitter API from my controller into a service:
angular.module('main')
.service('Tweet', function ($log, $http, Config, $ionicLoading) {
this.show = function () {
$ionicLoading.show({
template: '<ion-spinner></ion-spinner><br>Loading'
}).then(function () {
$log.log("The loading indicator is now displayed");
});
};
this.hide = function () {
$ionicLoading.hide().then(function () {
$log.log("The loading indicator is now hidden");
});
};
var consumerKey = encodeURIComponent(Config.TWITTER.CONSUMERKEY);
var consumerSecret = encodeURIComponent(Config.TWITTER.CONSUMERSECRET);
var tokenCredentials = btoa(consumerKey + ':' + consumerSecret);
this.getToken = function () {
this.show();
return $http({
method: 'POST',
url: 'https://api.twitter.com/oauth2/token',
headers: {
'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8',
'Authorization': 'Basic ' + tokenCredentials
},
data: 'grant_type=client_credentials'
})
.then(function (result) {
if (result.data && result.data.access_token) {
$http.defaults.headers.common.Authorization = 'Bearer ' + result.data.access_token;
}
})
.catch(function (error) {
console.log(error);
});
};
this.getTimeline = function () {
$log.log($http.defaults.headers.common.Authorization);
return $http({
method: 'GET',
url: 'https://api.twitter.com/1.1/search/tweets.json?q=%40postbank',
headers: {
'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8'
}
})
.then(function (result) {
return result.data.statuses;
})
.catch(function (error) {
console.log(error);
});
};
this.analyzeResult = function (input) {
this.tweets = input;
this.hide();
};
var that = this;
this.getTweets = function () {
this.getToken()
.then(this.getTimeline)
.then(function (result) {
that.analyzeResult(result);
});
}
});
I inject the service into my main controller and call the getTweets() function:
angular.module('main')
.controller('MainCtrl', function ($log, Tweet) {
Tweet.getTweets();
});
I can see that all the promises are executed through the console, but this.tweets stays empty. How do I send the data that is coming from the service/promise to the controller?

Answer 1

this within service constructor is service's context, not controller's. And services shouldn't operate on the scope.
Unwrap service promise in controller:
var self = this;
Tweet.getTweets().then(function () {
self.tweets = input;
});