AngularJs messaging service/directive

messagingService.js

.directive('postMessage', ['$window', 'postMessageService', function($window, postMessageService) {
		return {
			restrict: 'A',
			controller: function($scope, $attrs, postMessageService) {
				$scope.$on('outgoingMessage', function(evt, payload, targetOrigin, responseCallback) {
//					console.log('Caught Message:');
//					console.log(payload);
					if ($scope.sender) {
						var message = {
							status: 200,
							payload: payload
						};

						if(responseCallback){
							var
								timestamp = new Date().getTime(),
								requestId = CryptoJS.SHA1(timestamp.toString()).toString(CryptoJS.enc.Base64);

							if(!$scope.responseCallbacks){
								$scope.responseCallbacks = [];
							}
							$scope.responseCallbacks[requestId] = responseCallback;
							message.requestId = requestId;
						}
						message = JSON.stringify(message);
						try {
							$scope.sender.postMessage(message, targetOrigin);
						} catch (err){
							if(message.method && message.method != 'connect'){
								console.error(err);
							}
						}
					}
				});
			},
			link: function postLink(scope, element, attrs) {
				scope.sendMessageToService = function(e) {
					if (e && e.data) {
						var response = null;
						scope.sender = e.source;
						try {
							response = angular.fromJson(e.data);
						} catch (error) {
							response = {
								message: e.data
							}
						}
						if(
							response.requestId &&
								scope.responseCallbacks &&
								typeof scope.responseCallbacks[response.requestId] === 'function'
							){
							scope.responseCallbacks[response.requestId](response, e);
							scope.responseCallbacks.splice(response.requestId, 1);
						}
						postMessageService.messages(response);
					}
				};
				window.addEventListener('message', scope.sendMessageToService);
			}
		}
	}])
	.factory('postMessageService', ['$rootScope', function($rootScope) {
		var $messages = [];
		var api = {
			messages: function(_message_) {
				if (_message_) {
					$messages.push(_message_);
					$rootScope.$apply();
				}
				return $messages;
			},
			outgoing: function(message, targetOrigin, responseCallback) {
				$rootScope.$broadcast('outgoingMessage', message, targetOrigin, responseCallback);
			}
		};
		return api;
	}])