Angular $httpProvider interceptor to handle requests and also cancels request on state change

config.js

/**
 * This array is needed for canceling requests when changing the state/route.
 * @type {Array}
 */
var currentRequests = [];

/**
 * Handles route changes.
 */
app.run(['$rootScope', function($rootScope) {

  /**
   * Cancels pending requests
   */
  $rootScope.$on('$stateChangeSuccess', function(event, toState, toParams, fromState, fromParams) {
    angular.forEach(currentRequests, function(request) {
      request.resolve(); // cancel
    });
    currentRequests = [];
  });

}]);

/**
 * Authentication with token and email for every server request. (Sets HTTP headers)
 *
 * This interceptor shows the error from the server (i18n key).
 * Also sets global error variable if the request fails and redirects the user to '/' when he is not authorized.
 * @see http://engineering.talis.com/articles/client-side-error-logging/
 */
app.factory('authInterceptor', ['$rootScope', '$q', '$cookies', '$location', '$timeout', function ($rootScope, $q, $cookies, $location, $timeout) {
  return {
    request: function (config) {
      delete $rootScope.errorKey;

      config.headers = config.headers || {};
      config.headers['X-AUTH-TOKEN'] = $cookies['AUTH-TOKEN'];
      config.headers['X-AUTH-EMAIL'] = $cookies['AUTH-EMAIL'];

      if(!/\.html/.test(config.url)) {
        var defer = $q.defer();
        currentRequests.push(defer);
        config.timeout = defer.promise;
      }

      return config;
    },
    responseError: function (response) {
      var status = response.status;

      // unauthorized -> redirect
      if(status === 401) {

        $rootScope.error = 'global.server_errors.unauthorized';
        $timeout(function () {
          $location.path('/');
        }, 3000);

      } else if(status !== 0) {
        $rootScope.showErrorMsg = true; // general error message
        $timeout(function() {
          $rootScope.showErrorMsg = false;
        }, 10000);
      }
      return $q.reject(response);
    }
  };
}]);

app.config(['$httpProvider', function($httpProvider) {
  $httpProvider.interceptors.push('authInterceptor');
}]);