httpInterceptor for broadcasting open events

gistfile1.js

.factory('httpInterceptor', function($q, $injector, $rootScope){
                var $http;

                function open(num){
                    $rootScope.$broadcast('httpOpen', num);
                }
                function close(num){
                    $rootScope.$broadcast('httpClose', num);
                }
                return function(promise){
                    $http || ($http = $injector.get('$http'));
                    open($http.pendingRequests.length);
                    return promise.then(
                        function(response){
                            close($http.pendingRequests.length);
                            return response;
                        },
                        function(response){
                            close($http.pendingRequests.length);
                            return $q.reject(response);
                        }
                    );
                };
            })