AngularJS factory http returns empty

You should modify your code to return a promise and use the value in controller pls see dummy modified code

myDemo.factory('photosFactory', function($http) {
 return{
    getPhotos : function() {
        return $http({
            url: 'content/test_data.json',
            method: 'GET'
        })
    }
 }
});

and controller –

controllers.AppCtrl = function($scope, $location, $http, photosFactory) {
    $scope.photos = [];
    photosFactory.getPhotos().success(function(data){
       $scope.photos=data;
   });
};