Redirecting to a certain route based on condition

Question

I'm writing a small AngularJS app that has a login view and a main view, configured like so:

$routeProvider
 .when('/main' , {templateUrl: 'partials/main.html',  controller: MainController})
 .when('/login', {templateUrl: 'partials/login.html', controller: LoginController})
 .otherwise({redirectTo: '/login'});

My LoginController checks the user/pass combination and sets a property on the $rootScope reflecting this:

function LoginController($scope, $location, $rootScope) {
 $scope.attemptLogin = function() {
   if ( $scope.username == $scope.password ) { // test
        $rootScope.loggedUser = $scope.username;
        $location.path( "/main" );
    } else {
        $scope.loginError = "Invalid user/pass.";
    }
}

Everything works, but if I access http://localhost/#/main I end up bypassing the login screen. I wanted to write something like "whenever the route changes, if $rootScope.loggedUser is null then redirect to /login"

...

... wait. Can I listen to route changes somehow? I'll post this question anyway and keep looking.

Answer 1

In your app.js file:

.run(["$rootScope", "$state", function($rootScope, $state) {

      $rootScope.$on('$locationChangeStart', function(event, next, current) {
        if (!$rootScope.loggedUser == null) {
          $state.go('home');
        }    
      });
}])

Answer 2

Here is maybe a more elegant and flexible solution with 'resolve' configuration property and 'promises' enabling eventual data loading on routing and routing rules depending on data.

You specify a function in 'resolve' in routing config and in the function load and check data, do all redirects. If you need to load data, you return a promise, if you need to do redirect - reject promise before that. All details can be found on $routerProvider and $q documentation pages.

'use strict';

var app = angular.module('app', [])
    .config(['$routeProvider', function($routeProvider) {
        $routeProvider
            .when('/', {
                templateUrl: "login.html",
                controller: LoginController
            })
            .when('/private', {
                templateUrl: "private.html",
                controller: PrivateController,
                resolve: {
                    factory: checkRouting
                }
            })
            .when('/private/anotherpage', {
                templateUrl:"another-private.html",
                controller: AnotherPriveController,
                resolve: {
                    factory: checkRouting
                }
            })
            .otherwise({ redirectTo: '/' });
    }]);

var checkRouting= function ($q, $rootScope, $location) {
    if ($rootScope.userProfile) {
        return true;
    } else {
        var deferred = $q.defer();
        $http.post("/loadUserProfile", { userToken: "blah" })
            .success(function (response) {
                $rootScope.userProfile = response.userProfile;
                deferred.resolve(true);
            })
            .error(function () {
                deferred.reject();
                $location.path("/");
             });
        return deferred.promise;
    }
};

For russian-speaking folks there is a post on habr "Вариант условного раутинга в AngularJS."

Answer 3

I have been trying to do the same. Came up with another simpler solution after working with a colleague. I have a watch set up on $location.path(). That does the trick. I am just starting to learn AngularJS and find this to be more cleaner and readable.

$scope.$watch(function() { return $location.path(); }, function(newValue, oldValue){  
    if ($scope.loggedIn == false && newValue != '/login'){  
            $location.path('/login');  
    }  
});

Answer 4

If you do not want to use angular-ui-router, but would like to have your controllers lazy loaded via RequireJS, there are couple of problems with event $routeChangeStart when using your controllers as RequireJS modules (lazy loaded).

You cannot be sure the controller will be loaded before $routeChangeStart gets triggered -- in fact it wont be loaded. That means you cannot access properties of next route like locals or $$route because they are not yet setup.
Example:

app.config(["$routeProvider", function($routeProvider) {
    $routeProvider.when("/foo", {
        controller: "Foo",
        resolve: {
            controller: ["$q", function($q) {
                var deferred = $q.defer();
                require(["path/to/controller/Foo"], function(Foo) {
                    // now controller is loaded
                    deferred.resolve();
                });
                return deferred.promise;
            }]
        }
    });
}]);

app.run(["$rootScope", function($rootScope) {
    $rootScope.$on("$routeChangeStart", function(event, next, current) {
        console.log(next.$$route, next.locals); // undefined, undefined
    });
}]);

This means you cannot check access rights in there.

Solution:

As loading of controller is done via resolve, you can do the same with your access control check:

app.config(["$routeProvider", function($routeProvider) {
    $routeProvider.when("/foo", {
        controller: "Foo",
        resolve: {
            controller: ["$q", function($q) {
                var deferred = $q.defer();
                require(["path/to/controller/Foo"], function(Foo) {
                    // now controller is loaded
                    deferred.resolve();
                });
                return deferred.promise;
            }],
            access: ["$q", function($q) {
                var deferred = $q.defer();
                if (/* some logic to determine access is granted */) {
                    deferred.resolve();
                } else {
                    deferred.reject("You have no access rights to go there");
                }
                return deferred.promise;
            }],
        }
    });
}]);

app.run(["$rootScope", function($rootScope) {
    $rootScope.$on("$routeChangeError", function(event, next, current, error) {
        console.log("Error: " + error); // "Error: You have no access rights to go there"
    });
}]);

Note here that instead of using event $routeChangeStart I'm using $routeChangeError

Answer 5

1. Set global current user.

In your authentication service, set the currently authenticated user on the root scope.

// AuthService.js

  // auth successful
  $rootScope.user = user

2. Set auth function on each protected route.

// AdminController.js

.config(function ($routeProvider) {
  $routeProvider.when('/admin', {
    controller: 'AdminController',
    auth: function (user) {
      return user && user.isAdmin
    }
  })
})

3. Check auth on each route change.

// index.js

.run(function ($rootScope, $location) {
  $rootScope.$on('$routeChangeStart', function (ev, next, curr) {
    if (next.$$route) {
      var user = $rootScope.user
      var auth = next.$$route.auth
      if (auth && !auth(user)) { $location.path('/') }
    }
  })
})

Alternatively you can set permissions on the user object and assign each route a permission, then check the permission in the event callback.

Answer 6

After some diving through some documentation and source code, I think I got it working. Perhaps this will be useful for someone else?

I added the following to my module configuration:

angular.module(...)
 .config( ['$routeProvider', function($routeProvider) {...}] )
 .run( function($rootScope, $location) {

    // register listener to watch route changes
    $rootScope.$on( "$routeChangeStart", function(event, next, current) {
      if ( $rootScope.loggedUser == null ) {
        // no logged user, we should be going to #login
        if ( next.templateUrl != "partials/login.html" ) {
          // not going to #login, we should redirect now
          $location.path( "/login" );
        }
      }         
    });
 })

The one thing that seems odd is that I had to test the partial name (login.html) because the "next" Route object did not have a url or something else. Maybe there's a better way?