AngularJS - show/hide nav items if user is logged in

Question

I have a single-page AngularJS app, working with Express, node.js, and MongoDB via Mongoose. Using Passport for user management/authentication.

I'd like the navbar items to change based on whether a user is logged in or not. I'm having trouble figuring out how to implement it.

I find out if a user is logged in through an http request:

server.js

app.get('/checklogin',function(req,res){
  if (req.user)
    res.send(true);
  else
    res.send(false);

On the front end, I have a NavController calling this using Angular's $http service:

NavController.js

angular.module('NavCtrl',[]).controller('NavController',function($scope,$http) {

    $scope.loggedIn = false;

    $scope.isLoggedIn = function() {

      $http.get('/checklogin')
        .success(function(data) {
          console.log(data);
          if (data === true)
            $scope.loggedIn = true;
          else
            $scope.loggedIn = false;
        })
        .error(function(data) {
          console.log('error: ' + data);
        });
    };
};

In my nav, I am using ng-show and ng-hide to determine which selections should be visible. I am also triggering the isLoggedIn() function when the user clicks on the nav items, checking whether the user is logged in during each click.

index.html

<nav class="navbar navbar-inverse" role="navigation">
  <div class="navbar-header">
    <a class="navbar-brand" href="/">Home</a>
  </div>
  <ul class="nav navbar-nav">
    <li ng-hide="loggedIn" ng-click="isLoggedIn()">
      <a href="/login">Login</a>
    </li>
    <li ng-hide="loggedIn" ng-click="isLoggedIn()">
      <a href="/signup">Sign up</a>
    </li>
    <li ng-show="loggedIn" ng-click="logOut(); isLoggedIn()">
      <a href="#">Log out</a>
    </li>
  </ul>
</nav>

Problem

There are other places in my app where the user can log in/out, outside of the scope of the NavController. For instance, there's a login button on the login page, which corresponds to the LoginController. I imagine there's a better way to implement this across my entire app.

How can I 'watch' whether req.user is true on the back end and have my nav items respond accordingly?

Answer 1

you can use $rootScope to share info across the entire app:

.controller('NavController',function($scope,$http, $rootScope) {

    $scope.isLoggedIn = function() {

      $http.get('/checklogin')
        .success(function(data) {
          console.log(data);
          $rootScope.loggedIn = data;
        })
        .error(function(data) {
          console.log('error: ' + data);
        });
    };
};

now you can change the value of loggedIn from other places in your app by accessing $rootScope.loggedIn in the same way it is done in the code above.

With that said, you should abstract the relevant code into a service and a directive. This would allow you to have one central place to handle, log in, log out, and the state of $rootScope.loggedIn. If you post the rest of the relevant code I could help you out with a more concrete answer

Answer 2

You can broadcast that event when user logs in successfully. And no need to keep polling your server if user is logged in you can keep a variable in memory that tells if you have a valid session or not. You can use a token-based authentication which is set in the server side:

services.factory('UserService', ['$resource',                                        
  function($resource){

    // represents guest user - not logged
    var user = {
        firstName : 'guest',
        lastName : 'user',
        preferredCurrency : "USD",
        shoppingCart : {
            totalItems : 0,
            total : 0
        },                                                  
    };

    var resource = function() {
        return $resource('/myapp/rest/user/:id', 
            { id: "@id"}
    )};

    return {
        getResource: function() { 
            return resource;
        },

        getCurrentUser: function() {
            return user;
        },

        setCurrentUser: function(userObj) {
            user = userObj;
        },

        loadUser: function(id) {
            user = resource.get(id);
        }
    }

  }]);

services.factory('AuthService', ['$resource', '$rootScope', '$http', '$location', 'AuthenticationService', 
  function ($resource, $rootScope, $http, $location, AuthenticationService) {
    var authFactory = {
        authData: undefined       
    };

    authFactory.getAuthData = function () {
        return this.authData;
    };

    authFactory.setAuthData = function (authData) {
        this.authData = {
            authId: authData.authId,
            authToken: authData.authToken,
            authPermission: authData.authPermission
        };
        // broadcast the event to all interested listeners
        $rootScope.$broadcast('authChanged');
    };

    authFactory.isAuthenticated = function () {
        return !angular.isUndefined(this.getAuthData());
    };

    authFactory.login = function (user, functionObj) {
        return AuthenticationService.login(user, functionObj);          
    };

    return authFactory;
}]);

services.factory('AuthenticationService', ['$resource',
  function($resource){
    return $resource('/myapp/rest/auth/', 
            {},
            {
              'login': { method: "POST" }
            }               
    );
  }]);          

services.factory('authHttpRequestInterceptor', ['$injector',  
 function ($injector) {
    var authHttpRequestInterceptor = {
        request: function ($request) {
            var authFactory = $injector.get('AuthService');
            if (authFactory.isAuthenticated()) {
                $request.headers['auth-id'] = authFactory.getAuthData().authId;
                $request.headers['auth-token'] = authFactory.getAuthData().authToken;
            }
            return $request;
        }
    };

    return authHttpRequestInterceptor;
}]);

controller:

controllers.controller('LoginCtrl', ['$scope', '$rootScope', 'AuthService', 'UserService', 
  function LoginCtrl($scope, $rootScope, AuthService, UserService) {
    $scope.login = function () {
        AuthService.login($scope.userInfo, function (data) {
            AuthService.setAuthData(data);
            // set user info on user service to reflect on all UI components
            UserService.setCurrentUser(data.user);
            $location.path('/home/');               
        });
    };

    $scope.isLoggedIn = function () {
        return AuthService.isAuthenticated();
    }

    $scope.user = UserService.getCurrentUser();         
}])