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

38

I have the following code in the controller.js,

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

myApp.service('dataService', function($http) {
delete $http.defaults.headers.common['X-Requested-With'];
this.getData = function() {
    $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){
         return data
    }).error(function(){
        alert("error");
    });
 }
});

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

But, I think I m probably making a mistake with CORS related issue. Can you please point me to the correct way to make this call? Thanks much!

This question is tagged with javascript angularjs http get cross-domain

~ Asked on 2013-12-04 07:20:31

The Best Answer is


79

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.

~ Answered on 2013-12-04 07:42:43


9

I suggest you use Promise

myApp.service('dataService', function($http,$q) {

  delete $http.defaults.headers.common['X-Requested-With'];
  this.getData = function() {
     deferred = $q.defer();
     $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, we can resolve promise and we can access it in controller
         deferred.resolve();
     }).error(function(){
          alert("error");
          //let the function caller know the error
          deferred.reject(error);
     });
     return deferred.promise;
  }
});

so In your controller you can use the method

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

promises are powerful feature of angularjs and it is convenient special if you want to avoid nesting callbacks.

~ Answered on 2014-08-15 10:12:03


Most Viewed Questions: