Processing $http response in service

Here is a Plunk that does what you want: http://plnkr.co/edit/TTlbSv?p=preview

The idea is that you work with promises directly and their "then" functions to manipulate and access the asynchronously returned responses.

app.factory('myService', function($http) {
  var myService = {
    async: function() {
      // $http returns a promise, which has a then function, which also returns a promise
      var promise = $http.get('test.json').then(function (response) {
        // The then function here is an opportunity to modify the response
        console.log(response);
        // The return value gets picked up by the then in the controller.
        return response.data;
      });
      // Return the promise to the controller
      return promise;
    }
  };
  return myService;
});

app.controller('MainCtrl', function( myService,$scope) {
  // Call the async method and then do stuff with what is returned inside our own then function
  myService.async().then(function(d) {
    $scope.data = d;
  });
});

Here is a slightly more complicated version that caches the request so you only make it first time (http://plnkr.co/edit/2yH1F4IMZlMS8QsV9rHv?p=preview):

app.factory('myService', function($http) {
  var promise;
  var myService = {
    async: function() {
      if ( !promise ) {
        // $http returns a promise, which has a then function, which also returns a promise
        promise = $http.get('test.json').then(function (response) {
          // The then function here is an opportunity to modify the response
          console.log(response);
          // The return value gets picked up by the then in the controller.
          return response.data;
        });
      }
      // Return the promise to the controller
      return promise;
    }
  };
  return myService;
});

app.controller('MainCtrl', function( myService,$scope) {
  $scope.clearData = function() {
    $scope.data = {};
  };
  $scope.getData = function() {
    // Call the async method and then do stuff with what is returned inside our own then function
    myService.async().then(function(d) {
      $scope.data = d;
    });
  };
});

Because it is asynchronous, the $scope is getting the data before the ajax call is complete.

You could use $q in your service to create promise and give it back to controller, and controller obtain the result within then() call against promise.

In your service,

app.factory('myService', function($http, $q) {
  var deffered = $q.defer();
  var data = [];  
  var myService = {};

  myService.async = function() {
    $http.get('test.json')
    .success(function (d) {
      data = d;
      console.log(d);
      deffered.resolve();
    });
    return deffered.promise;
  };
  myService.data = function() { return data; };

  return myService;
});

Then, in your controller:

app.controller('MainCtrl', function( myService,$scope) {
  myService.async().then(function() {
    $scope.data = myService.data();
  });
});

Let it be simple. It's as simple as

1. Return promise in your service(no need to use then in service)
2. Use then in your controller

Demo. http://plnkr.co/edit/cbdG5p?p=preview

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

app.factory('myService', function($http) {
  return {
    async: function() {
      return $http.get('test.json');  //1. this returns promise
    }
  };
});

app.controller('MainCtrl', function( myService,$scope) {
  myService.async().then(function(d) { //2. so you can use .then()
    $scope.data = d;
  });
});

tosh shimayama have a solution but you can simplify a lot if you use the fact that $http returns promises and that promises can return a value:

app.factory('myService', function($http, $q) {
  myService.async = function() {
    return $http.get('test.json')
    .then(function (response) {
      var data = reponse.data;
      console.log(data);
      return data;
    });
  };

  return myService;
});

app.controller('MainCtrl', function( myService,$scope) {
  $scope.asyncData = myService.async();
  $scope.$watch('asyncData', function(asyncData) {
    if(angular.isDefined(asyncData)) {
      // Do something with the returned data, angular handle promises fine, you don't have to reassign the value to the scope if you just want to use it with angular directives
    }
  });

});

A little demonstration in coffeescript: http://plunker.no.de/edit/ksnErx?live=preview

Your plunker updated with my method: http://plnkr.co/edit/mwSZGK?p=preview

A much better way I think would be something like this:

Service:

app.service('FruitsManager',function($q){

    function getAllFruits(){
        var deferred = $q.defer();

        ...

        // somewhere here use: deferred.resolve(awesomeFruits);

        ...

        return deferred.promise;
    }

    return{
        getAllFruits:getAllFruits
    }

});

And in the controller you can simply use:

$scope.fruits = FruitsManager.getAllFruits();

Angular will automatically put the resolved awesomeFruits into the $scope.fruits.

When binding the UI to your array you'll want to make sure you update that same array directly by setting the length to 0 and pushing the data into the array.

Instead of this (which set a different array reference to data which your UI won't know about):

 myService.async = function() {
    $http.get('test.json')
    .success(function (d) {
      data = d;
    });
  };

try this:

 myService.async = function() {
    $http.get('test.json')
    .success(function (d) {
      data.length = 0;
      for(var i = 0; i < d.length; i++){
        data.push(d[i]);
      }
    });
  };

Here is a fiddle that shows the difference between setting a new array vs emptying and adding to an existing one. I couldn't get your plnkr working but hopefully this works for you!

Related to this I went through a similar problem, but not with get or post made by Angular but with an extension made by a 3rd party (in my case Chrome Extension).
The problem that I faced is that the Chrome Extension won't return then() so I was unable to do it the way in the solution above but the result is still Asynchronous.
So my solution is to create a service and to proceed to a callback

app.service('cookieInfoService', function() {
    this.getInfo = function(callback) {
        var model = {};
        chrome.cookies.get({url:serverUrl, name:'userId'}, function (response) {
            model.response= response;
            callback(model);
        });
    };
});

Then in my controller

app.controller("MyCtrl", function ($scope, cookieInfoService) {
    cookieInfoService.getInfo(function (info) {
        console.log(info);
    });
});

Hope this can help others getting the same issue.

I've read http://markdalgleish.com/2013/06/using-promises-in-angularjs-views/ [AngularJS allows us to streamline our controller logic by placing a promise directly on the scope, rather than manually handing the resolved value in a success callback.]

so simply and handy :)

var app = angular.module('myApp', []);
            app.factory('Data', function($http,$q) {
                return {
                    getData : function(){
                        var deferred = $q.defer();
                        var promise = $http.get('./largeLoad').success(function (response) {
                            deferred.resolve(response);
                        });
                        // Return the promise to the controller
                        return deferred.promise; 
                    }
                }
            });
            app.controller('FetchCtrl',function($scope,Data){
                $scope.items = Data.getData();
            });

Hope this help

I really don't like the fact that, because of the "promise" way of doing things, the consumer of the service that uses $http has to "know" about how to unpack the response.

I just want to call something and get the data out, similar to the old $scope.items = Data.getData(); way, which is now deprecated.

I tried for a while and didn't come up with a perfect solution, but here's my best shot (Plunker). It may be useful to someone.

app.factory('myService', function($http) {
  var _data;  // cache data rather than promise
  var myService = {};

  myService.getData = function(obj) { 
    if(!_data) {
      $http.get('test.json').then(function(result){
        _data = result.data;
        console.log(_data);  // prove that it executes once
        angular.extend(obj, _data);
      }); 
    } else {  
      angular.extend(obj, _data);
    }
  };

  return myService;
}); 

Then controller:

app.controller('MainCtrl', function( myService,$scope) {
  $scope.clearData = function() {
    $scope.data = Object.create(null);
  };
  $scope.getData = function() {
    $scope.clearData();  // also important: need to prepare input to getData as an object
    myService.getData($scope.data); // **important bit** pass in object you want to augment
  };
});

Flaws I can already spot are

• You have to pass in the object which you want the data added to, which isn't an intuitive or common pattern in Angular
• getData can only accept the obj parameter in the form of an object (although it could also accept an array), which won't be a problem for many applications, but it's a sore limitation
• You have to prepare the input object $scope.data with = {} to make it an object (essentially what $scope.clearData() does above), or = [] for an array, or it won't work (we're already having to assume something about what data is coming). I tried to do this preparation step IN getData, but no luck.

Nevertheless, it provides a pattern which removes controller "promise unwrap" boilerplate, and might be useful in cases when you want to use certain data obtained from $http in more than one place while keeping it DRY.