Error in LInking service and directive in Angular

Question

I have an issue at linking service having http to a directive. This is the code of that...

    myapp.factory ( 'autoCompleteDataService', ['$http', function($http) {
   return {
       getSource: function(callback) {
          var url = 'get_data_from_server.php';
          $http.get(url).success(function(data) {
             callback(data);
          });
       }
   }
} ] );

myapp.directive('autoComplete', function(autoCompleteDataService) {
    return {
        restrict: 'A',
        link: function(scope, elem, attr, ctrl) {
            elem.autocomplete({
                source: autoCompleteDataService.getSource(), 
                select: function( event, ui ) {
                         scope.$apply(function() {
                           scope.item.unit_id = ui.item.value; 
                         });
                        },
                minLength: 2
            });
        }
    };
});

I replaced callback(data); with return data; with no result...

Any help is appreciated..

Edit: added working code without http

If I keep this code instead the above one its working

myapp.factory('autoCompleteDataService', [function() {
return {
    getSource: function() {
        return ['apples', 'oranges', 'bananas'];
    }
}

}]);

Answer 1

myapp.factory('autoCompleteDataService', ['$http', function($http) {
    return {
        getSource: function() {
            var url = 'get_data_from_server.php';
            return $http.get(url);
        }
    }
}]);

Directive:

link : function(scope, elem, attr, ctrl) {
    autoCompleteDataService.getSource().success(function(data) {
        elem.autocomplete({
            source: data, 
            select: function( event, ui ) {
                scope.$apply(function() { scope.item.unit_id = ui.item.value; });
            },
            change: function (event, ui) {
                if (ui.item === null) {
                    scope.$apply(function() { scope.foo = null });
                }
            },
            minLength: 2
        });
    });
}