How to use HTTP.GET in AngularJS correctly? In specific, for an external API call?

angularjs, cross-domain, get, http, javascript

Solution

First, your `success()` handler just returns the data, but that's not returned to the caller of `getData()` since it's already in a callback. `$http` is an asynchronous call that returns a `$promise`, so you have to register a callback for when the data is available.

I'd recommend looking up Promises and the $q library in AngularJS since they're the best way to pass around asynchronous calls between services.

For simplicity, here's your same code re-written with a function callback provided by the calling controller:

var myApp = angular.module('myApp',[]);

myApp.service('dataService', function($http) {
    delete $http.defaults.headers.common['X-Requested-With'];
    this.getData = function(callbackFunc) {
        $http({
            method: 'GET',
            url: 'https://www.example.com/api/v1/page',
            params: 'limit=10, sort_by=created:desc',
            headers: {'Authorization': 'Token token=xxxxYYYYZzzz'}
        }).success(function(data){
            // With the data succesfully returned, call our callback
            callbackFunc(data);
        }).error(function(){
            alert("error");
        });
     }
});

myApp.controller('AngularJSCtrl', function($scope, dataService) {
    $scope.data = null;
    dataService.getData(function(dataResponse) {
        $scope.data = dataResponse;
    });
});

Now, `$http` actually already returns a $promise, so this can be re-written:

var myApp = angular.module('myApp',[]);

myApp.service('dataService', function($http) {
    delete $http.defaults.headers.common['X-Requested-With'];
    this.getData = function() {
        // $http() returns a $promise that we can add handlers with .then()
        return $http({
            method: 'GET',
            url: 'https://www.example.com/api/v1/page',
            params: 'limit=10, sort_by=created:desc',
            headers: {'Authorization': 'Token token=xxxxYYYYZzzz'}
         });
     }
});

myApp.controller('AngularJSCtrl', function($scope, dataService) {
    $scope.data = null;
    dataService.getData().then(function(dataResponse) {
        $scope.data = dataResponse;
    });
});

Finally, there's better ways to configure the `$http` service to handle the headers for you using `config()` to setup the `$httpProvider`. Checkout the $http documentation for examples.

Problem

Original source