Angular state change after a promise - javascript

I'm not sure if this is a duplicate or not, but I didn't manage to find anything that worked for me, so I'm posting this question.
I have a situation where I need to get values from database before directing user to certain routes, so I could decide what content to show.
If I move e.preventDefault() right before $state.go(..) then it works, but not properly. Problem is that it starts to load default state and when it gets a response from http, only then it redirects to main.home. So let's say, if the db request takes like 2 seconds, then it takes 2 seconds before it redirects to main.home, which means that user sees the content it is not supposed to for approximately 2 seconds.
Is there a way to prevent default at the beginning of state change and redirect user at the end of state change?
Also, if we could prevent default at the beginning of state change, then how could we continue to default state?
(function(){
"use strict";
angular.module('app.routes').run(['$rootScope', '$state', '$http', function($rootScope, $state, $http){
/* State change start */
$rootScope.$on('$stateChangeStart', function(e, to, toParams, from, fromParams){
e.preventDefault();
$http
.get('/url')
.error(function(err){
console.log(err);
})
.then(function(response){
if( response.data === 2 ){
// e.preventDefault()
$state.go('main.home');
}
// direct to default state
})
}
}]);
});

You could add a resolve section to your $stateProviderConfig.
Inside the resolve you can make a request to the databse and check required conditions. If case you don't want user to acces this page you can use $state.go() to redirect him elsewhere.
Sample config:
.state({
name: 'main.home',
template: 'index.html',
resolve: {
accessGranted: ['$http', '$state', '$q',
function($http, $state, $q) {
let deffered = $q.defer();
$http({
method: 'GET',
url: '/url'
}).then(function(data) {
if (data === 2) {
// ok to pass the user
deffered.resolve(true);
} else {
//no access, redirect
$state.go('main.unauthorized');
}
}, function(data) {
console.log(data);
//connection error, redirect
$state.go('main.unauthorized');
});
return deffered.promise;
}
]
}
});
Documentation of the resolve is available here
Note that you could use Promise object instead of $q service in case you don't need to support IE

One way to handle this situation is adding an interceptor as follows.
.config(function ($httpProvider) {
$httpProvider.interceptors.push('stateChangeInterceptor');
}).factory('stateChangeInterceptor', function ($q, $window,$rootScope) {
return {
'response': function(response) {
var isValid = true;//Write your logic here to validate the user/action.
/*
* Here you need to allow all the template urls and ajax urls which doesn't
*/
if(isValid){
return response;
}
else{
$rootScope.$broadcast("notValid",{statusCode : 'INVALID'});
}
},
'responseError': function(rejection) {
return $q.reject(rejection);
}
}
})
Then handle the message 'notValid' as follows
.run(function($state,$rootScope){
$rootScope.$on("notValid",function(event,message){
$state.transitionTo('whereever');
});
})

Related

Show loading indicator at root level until all route resolves are complete

I've been doing some Googling around this already but I'm unable to find a solution that works.
I'm using AngularJS 1.5.5 and .NET Web API 2 to build a web application and I would quite simply like to hide the ng-view element until all resolves have completed on the route.
I'm trying to use the $routeChangeStart and $routeChangeSuccess to set a variable on the $rootScope that is used in the index html to display the loading indicator and hide the content until the variable is false.
Here is my routing code for the routeChange properties:
_app.config([
'$routeProvider', '$httpProvider', '$provide',
function ($routeProvider, $httpProvider, $provide) {
$routeProvider.when('/Account',
{
templateUrl: '/Content/js/areas/account/account.html',
controller: 'accountController',
resolve: {
$accountResolver: function (accountService) {
return accountService.getMyAccountData();
}
},
caseInsensitiveMatch: true
});
$routeProvider.otherwise({ redirectTo: '404' });
}
]);
_app.run(['$rootScope', '$location', '$window', '$q', 'authService',
function ($rootScope, $location, $window, $q, authService) {
$rootScope.$on("$routeChangeStart",
function (e, curr, prev) {
$rootScope.$loadingRoute = true;
});
$rootScope.$on("$routeChangeSuccess",
function (evt, next) {
$rootScope.$loadingRoute = false;
});
$rootScope.$on("$routeChangeError",
function (evt, next) {
$rootScope.$loadingRoute = false;
});
}]);
And here is my html using that $loadingRoute variable:
<body class="ng-cloak" data-ng-app="wishlist" data-ng-controller="appController">
<wl-header></wl-header>
<preloader ng-if="$loadingRoute"></preloader>
<section ng-view ng-if="!$loadingRoute" class="container ng-cloak"></section>
</body>
I understand that there's quite a lot of articles covering this but none seem to work in my case. $loadingRoute gets set to true when the route change starts, as expected, which I will see if I add {{$loadingRoute}} to the HTML before the <section></section> tag. However before the $accountResolveris resolved, the $routeChangeSuccess gets fired, setting $rootScope.$loadingRoute = false which is unexpected.
I was under the impression that $routeChangeSuccess only got fired after all resolves had completed on the current route.
Am I doing something really obviously wrong here? Or has Angular simply changed?
Edit: I would also like to add that this approach worked in previous projects, so I'm at a real loss as to what's going wrong. I could set $rootScope.$loadingRoute manually in each page controller but that feels too dirty and unmaintainable.
Edit 2:
_app.factory('accountService', [
'accountResource',
function (accountResource) {
var _self = this;
return {
register: function (authData) {
return accountResource.register(authData);
},
getMyAccountData: function () {
return accountResource.getMyAccountData();
}
}
}
]);
_app.factory('accountResource', [
'$resource', 'rootUrl',
function ($resource, rootUrl) {
var api = rootUrl() + 'api/Account';
return $resource(api,
{},
{
register: {
method: 'POST',
url: '{0}/register'.format(api)
},
getMyAccountData: {
method: 'GET',
url: '{0}/GetMyAccountData'.format(api)
}
});
}
])
In order for a resolver to delay route change, it should return a promise. Otherwise route change happens immediately, this is what happens when $routeChangeSuccess is triggered before a promise from accountService.getMyAccountData() is resolved.
The problem is $resource methods (and so accountService.getMyAccountData()) return self-filling object that is populated with data asynchronously. A promise for this data is available as $promise property (see the reference), so it should be used for a resolver:
$accountResolver: function (accountService) {
return accountService.getMyAccountData().$promise;
}
If accountService is supposed to be purely promise-based wrapper for accountResource, a cleaner way to do this is to return a promise from its methods instead:
getMyAccountData: function () {
return accountResource.getMyAccountData().$promise;
}

Making AngularJS ui-router / app wait for $http data to prevent FOUC

I have the following question... or situation. I have states defined in my AngularJS app, like so...
$stateProvider
.state('myApp', {
abstract: true,
template: '<ui-view/>'
})
.state('myApp.stateOne', {
url: 'state1',
templateUrl: '/an/views/state-1.html',
controller: 'StateOneCtrl'
})
.state('myApp.stateTwo', {
url: 'state2',
templateUrl: '/an/views/state-2.html'
controller: 'StateTwoCtrl'
})
.state('myApp.stateThree', {
url: 'state3',
templateUrl: '/an/views/state-3.html'
controller: 'StateThreeCtrl'
})
There are more states and I have changed the naming for this example, but suppose I need to check if the user is allowed to see / load 'mayApp.stateThree'. I can determine this by asking the backend. I have a service (in this example called IsAllowedService) to deal with this requests / provide the access and normally I would write the logic to do the check in the .run() block in my app.js file for example:
.run(['IsAllowedService', '$state', function (IsAllowedService, $state) {
$rootScope.$on('$stateChangeSuccess', function (event, toState, toParams, fromState) {
// check if we are going to sfm.addContacts and if we are allowed to...
if (toState.name === 'myApp.stateThree') {
IsAllowedService.checkIfIsAllowed().then(function (resp) {
if(resp.allowed === false) {
$state.go('myApp.stateOne');
}
});
}
});
}]);
This works well but doesn't wait until we get the result from the service so 'mayApp.stateThree' is loaded then we a redirected if necessary. So we get a quick flash of the page before we are redirected. I could put the same code into the 'StateThreeCtrl' but I still get the flash / FOUC. Would it be possible to resolve this when defining the states, I know this won't work but something like this...
.state('myApp.stateThree', {
url: '/an/state3',
templateUrl: '/an/views/state-3.html'
controller: 'StateThreeCtrl',
resolve: {
isAllowed : function () {
IsAllowedService.checkIfIsAllowed().then(function (resp) {
return resp;
})
}
}
I realise that I wouldn't be able to inject the service (or even the $http service) but is it possible for me to somehow pause the loading of the view / controller of 'mayApp.stateThree' until I get the result from IsAllowedService.checkIfIsAllowed(). Any advice on how to structure my app / code would be appreciated. I have used ng-cloak in my HTML view but this did nothing!
Actually you're doing it almost right in the application's run block. Except you are not preventing anything. You can achieve that by adding:
event.preventDefault(); //Prevent from going to the page
Furthermore, you can add custom data to your $states , which will allow you to verify those conditions with your criteria. e.g.:
$stateProvider.state('home', {
controller: 'HomeController as home',
url: '/home',
templateUrl: 'home.html',
data: { roles: [ROLES.ANONYMOUS] }}); //This can be any condition
$stateProvider.state('user', {
controller: 'UserController as user',
url: '/user',
templateUrl: 'user.html',
data: { roles: [ROLES.ADMIN, ROLES.USER] }});
You can retrieve this custom data in the $stateChangeStart event:
$rootScope.$on('$stateChangeStart', function (event, next) {
if (!yourService.isAuthorized(next.data.roles)) {
event.preventDefault(); //Prevent from going to the page -> no flickering
$state.go('403'); //Or whatever is desired.
}
});
You see the flickering because you're using a Promise and the first page only gets redirected when the promise is furfilled. You can stop the flickering by preventing the default action, authorize and continue your flow as you desire when the promise resolves.
if (toState.name === 'myApp.stateThree') {
event.preventDefault(); //preventing the request.
IsAllowedService.checkIfIsAllowed().then(function (resp) {
if(resp.allowed === false) {
$state.go('myApp.stateOne');
} else { //he actually is allowed to go to state three.
$state.go('myApp.stateThree');
}
}, function() { //in case the server has no answer
$state.go('myApp.stateOne'); //you probably want to prevent it too
} );
In my opinion, if these conditions do not change during runtime, i.e. user role based, you can retrieve them upon user verification so you don't need a promise to begin with. Hope this helps.
I made a similar post before and added a working plunker.

Plugging a custom service to UI Route

I have developed an app which uses succesfully ADAL JS library for authentication with azure. However I also need to implement authorization, and I meant that I need to restrict views to specific groups.
I already have a REST API which given a user id or email can return me the groups he belongs to.
However I am not sure how to plug an angular service to cosume that REST API and plug that into the routes configuration.
app.js
(function () {
angular.module('inspinia', [
'ui.router', // Routing
'oc.lazyLoad', // ocLazyLoad
'ui.bootstrap', // Ui Bootstrap
'pascalprecht.translate', // Angular Translate
'ngIdle', // Idle timer
'AdalAngular', // ADAL JS Angular
'ngRoute' // Routing
])
})();
config.js
function config($stateProvider, $urlRouterProvider, $ocLazyLoadProvider, IdleProvider, KeepaliveProvider,adalAuthenticationServiceProvider, $httpProvider) {
// Configure Idle settings
IdleProvider.idle(5); // in seconds
IdleProvider.timeout(120); // in seconds
$urlRouterProvider.otherwise("/dashboards/dashboard_1");
$ocLazyLoadProvider.config({
// Set to true if you want to see what and when is dynamically loaded
debug: false
});
$stateProvider
.state('dashboards', {
abstract: true,
url: "/dashboards",
templateUrl: "views/common/content.html",
})
.state('dashboards.dashboard_1', {
url: "/dashboard_1",
templateUrl: "views/dashboard_1.html",
requireADLogin: true,
resolve: {
loadPlugin: function ($ocLazyLoad) {
return $ocLazyLoad.load([
{
serie: true,
name: 'angular-flot',
files: [ 'js/plugins/flot/jquery.flot.js', 'js/plugins/flot/jquery.flot.time.js', 'js/plugins/flot/jquery.flot.tooltip.min.js', 'js/plugins/flot/jquery.flot.spline.js', 'js/plugins/flot/jquery.flot.resize.js', 'js/plugins/flot/jquery.flot.pie.js', 'js/plugins/flot/curvedLines.js', 'js/plugins/flot/angular-flot.js', ]
},
{
name: 'angles',
files: ['js/plugins/chartJs/angles.js', 'js/plugins/chartJs/Chart.min.js']
},
{
name: 'angular-peity',
files: ['js/plugins/peity/jquery.peity.min.js', 'js/plugins/peity/angular-peity.js']
}
]);
}
}
})
Ideally it would be awesome i could add a new property to each state called Groups with values:
Something like:
url: "/dashboard_1",
templateUrl: "views/dashboard_1.html",
requireADLogin: true,
groups: "Admin, Accounting, Marketing"
and then the custom service under the hood will validate this.
I'm not familiar specifically with ADAL.js, but assuming you can say to the server, "does this user have any of these roles" in a http request, then you could intercept the $stateChangeStart, prevent the state change by calling event.preventDefault(), ask the server if the current user is in any of roles specified for in the toState as having access and then take action either way - send to an access denied page, or continue on to the toState.
The following is a flawed implementation. The working version is locked away at work, and I'm at home right now, but hopefully it will give you some ideas.
(function (app) {
"use strict";
app.run(run);
function run($rootScope, $log, $state, $q, authService) {
/**
* The canceller is passed to the authService.isTokenValid()
*
* The canceller is a promise, that, when resolved, cancels the current
* token validation request
*/
let _canceller;
/**
* When state is changed, ensure that the current user has access
* #param event
* #param toState
*/
function onStateChangeStart(event, toState, toParams) {
// When token is valid, continue with navigation to the state
function onValidToken() {
if (toState.name === 'login'){
$state.go('home');
} else {
$state.go(toState, toParams, {notify: false}).then((state) => {
$rootScope.$broadcast('$stateChangeSuccess', state, null);
});
}
}
// When the token is not valid, set state to login
function onInvalidToken() {
if (toState.name === 'login'){
$state.go(toState, toParams, {notify: false}).then((state) => {
$rootScope.$broadcast('$stateChangeSuccess', state, null);
});
} else {
$log.warn(`Access denied to state ${toState.name}`);
$state.go('login');
}
}
// On completion of token validation, resolve the canceller
function onFinally() {
if (_canceller) {
_canceller.resolve();
}
}
// If the state requiresLogin
if (toState.requiresLogin || toState.name === 'login') {
// stop navigation
event.preventDefault();
// Cancel any current requests
if (_canceller) {
_canceller.resolve();
}
// create a new promise
_canceller = $q.defer();
// validate
authService.isTokenValid(_canceller)
.then(onValidToken, onInvalidToken)
.finally(onFinally);
}
}
$rootScope.$on('$stateChangeStart', onStateChangeStart);
}
}(angular.module('app.features')));

Handling error in AngularJS when consuming WebApi

In the code below, I'd like handling errors :
401 : redirect to a login page
other : display error message (received in the message of the error)
I don't find the right way to do this.
Any idea ?
Thanks,
Module.js
var app;
(function () {
app = angular.module("studentModule", []);
})()
Service.js
app.service('StudentService', function ($http) {
this.getAllStudent = function () {
return $http.get("http://myserver/api/Student/");
}
});
Controller.js
app.controller('studentController', function ($scope, StudentService) {
function GetAllRecords() {
var promiseGet = StudentService.getAllStudent();
promiseGet.then(function (pl) { $scope.Students = pl.data },
function (errorPl) {
$log.error('Some Error in Getting Records.', errorPl);
});
}
});
As with most problems, there are many different ways to handle errors from AJAX requests in AngularJS. The easiest is to use an HTTP interceptor as already pointed out. This can handle both authentication and errors.
app.config(['$httpProvider', function($httpProvider) {
$httpProvider.interceptors.push(['$rootScope', '$q', function($rootScope, $q) {
return {
responseError: function(rejection) {
var deferred;
// If rejection is due to user not being authenticated
if ( rejection.status === 401 ) {
$rootScope.$broadcast('unauthenticated', rejection);
// Return a new promise since this error can be recovered
// from, like redirecting to login page. The rejection and
// and promise could potentially be stored to be re-run
// after user is authenticated.
deferred = $q.defer();
return deferred.promise;
}
$rootScope.$broadcast('serverError', rejection);
// Just reject since this probably isn't recoverable from
return $q.reject(rejection);
}
}
};
}]);
The above interceptor is created using an anonymous function but factories can be used to handle one or many different interceptors. The AngularJS docs have decent information about how to write different ones: https://docs.angularjs.org/api/ng/service/$http#interceptors
With the interceptors in place, you now just need to listen from the broadcasted events in your run method or any controller.
app.run(['$rootScope', '$location', function($rootScope, $location) {
$rootScope.$on('unauthenticated', function(response) {
// Redirect to login page
$location.path('/login');
});
$rootScope.$on('serverError', function(response) {
// Show alert or something to give feedback to user that
// server error was encountered and they need to retry
// or just display this somewhere on the page
$rootScope.serverError = response.data.errorMessage;
});
}]);
In your view:
<body ng-app="studentModule">
<div id="server_error" ng-if="!!serverError">{{serverError}}</div>
...rest of your page
</body>
Like almost all AngularJS code, most of this can be abstracted into different factories and services but this should be a good place to start.

Change state of angular app from resolve method of state provider

I'm using ui-router in my angular application. Currently I've two routes /signin & /user.
Initially it shows /signin when the user clicks on the login button, I'm sending a ajax request and getting the user id. I'm storing the user id in localstorage and changing the state to /user.
Now, what I want, if a user is not loggedin, and user changes the addressbar to /user, it'll not change the view, instead it'll change the addressbar url to /signin again.
I'm try to use resolve, but it's not working. My code is:-
module.exports = function($stateProvider, $injector) {
$stateProvider
.state('signin', {
url: '/signin',
template: require('../templates/signin.html'),
controller: 'LoginController'
})
.state('user', {
url: '/user/:id',
template: require('../templates/user.html'),
resolve:{
checkLogin: function(){
var $state = $injector.get('$state');
console.log("in resolve");
if (! window.localStorage.getItem('user-id')) {
console.log("in if")
$state.go('signin');
}
}
},
controller: 'UserController'
})
}
Please help me to solve this problem.
I don't think it's allowed to change states in the middle of a state transition.
So, the way to address it is to have the checkLogin resolve parameter (I changed it below to userId) to be a function that either returns a value or a promise (in this case, a rejected promise, if you can't get the user-id).
You'd then need to handle this in $rootScope.$on('$stateChangeError') and check the error code.
resolve: {
userId: function ($q, $window) {
var userId = $window.localStorage.getItem('user-id');
if (!userId) {
return $q.reject("signin")
}
return userId;
}
}
And redirect in the $stateChangeError handler:
$rootScope.$on('$stateChangeError', function (event, toState, toParams, fromState, fromParams, error) {
if (error === "signin") {
$state.go("signin");
}
});
If someone has this problem, you can solve it, using timeout service. It will put state switching call at the end of queue.
Also, you should use promises. Rejecting it will prevent initialization of that state:
resolve:{
checkLogin: function(){
var deferred = $q.defer();
var $state = $injector.get('$state');
if (!window.localStorage.getItem('user-id')) {
$timeout(function(){$state.go('signin');});
deferred.reject();
} else {
deferred.resolve();
}
return deferred.promise;
}
},

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