“No provider for AuthGuard!” using CanActivate in

问题:

EDIT : Obviously this is outdated, now you provide your guard at the providers array in an NgModule. Watch other answers or official documentation for more information.

• bootstrapping on a component is outdated
• provideRouter() is outdated as well

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---

I'm trying to setup Authentication in my project, using a login and AuthGuard from the Angular2 guide : https://angular.io/docs/ts/latest/guide/router.html

I'm using the release : "@angular/router": "3.0.0-beta.1".

I'll try to explain as much as possible, feel free to tell me if you need more details.

---

I have my main.ts file which boostraps the app with the following code :

bootstrap(MasterComponent, [
    APP_ROUTER_PROVIDERS,
    MenuService
])
.catch(err => console.error(err));

I load the MasterComponent, which loads a Header containing buttons that allow me to navigate through my app and it also contains my main for now.

I'm following the guide to make my app work the same way, with the following app.routes.ts :

export const routes: RouterConfig = [
    ...LoginRoutes,
    ...MasterRoutes
];

export const APP_ROUTER_PROVIDERS = [
    provideRouter(routes),
    AUTH_PROVIDERS
];

And the login.routes.ts from the guide, which defines my AuthGuard :

export const LoginRoutes = [
    { path: 'login', component: LoginComponent }
];

export const AUTH_PROVIDERS = [AuthGuard, AuthService];

my Master component has its own route definition, which also contains the guard I'm trying to setup. master.routes.ts :

export const MasterRoutes : RouterConfig = [
    { path: '', redirectTo: '/accueil', pathMatch: 'full' },

    {
        path: 'accueil',
        component: AccueilComponent
    },

    { path: 'dashboard', component: DashboardComponent, canActivate: [AuthGuard] },
];

And I'm using the same files as the guide, which are auth.guard.ts, auth.service.ts, login.component.ts and login.routes.ts.

---

In my header.component.ts file, when I try to access any routes, it's working just fine, but when I try to access the guarded path (/dashboard), I get the No provider for AuthGuard! error.

I saw the recent post with the same issue as mine (NoProviderError using CanActivate in Angular 2), but to me the guard is bootstraped correctly up to the main.ts file, so my router should know which routes should be provided with the AuthGuard right ?

Any help or advice would be greatly appreciated. Thanks !

回答1:

I had this same issue after going through the Route Guards section of Routing and Authorization tutorial on the Angular website https://angular.io/docs/ts/latest/guide/router.html, it is section 5.

I am adding AuthGuard to one of my main routes and not to child routes like the tutorial shows.

I fixed it by added AuthGuard to my list of providers in my app.module.ts file, so that file now looks like this:

import { AppComponent } from './app.component';
import {AppRoutingModule} from './app-routing.module';
import {AuthGuard} from './auth-gaurd.service';

import { AnotherPageComponent } from './another-page/another-page.component';
import { LoginPageComponent } from './login-page/login-page.component';

@NgModule({
  imports: [
    BrowserModule,
    FormsModule,
    JsonpModule,
    AppRoutingModule,
    HttpModule
  ],
  declarations: [
    AppComponent,
    LoginPageComponent,
    AnotherPageComponent
  ],
  providers: [AuthGuard],
  bootstrap: [AppComponent]
})

export class AppModule { }

I have gone back through the tutorial and in their app.module.ts file, they do not add AuthGuard to the providers, not sure why.

回答2:

Also, don't fall into the trap of using a literal for the guard class inside your routing configuration, just because some blog articles do:

{ path: 'whatever', component: WhatEverComponent, canActivate: ['WhatEverGuard'] }

is not going to work (No provider for...), instead, use the class directly:

{ path: 'whatever', component: WhatEverComponent, canActivate: [WhatEverGuard] }

Another hint, when lazy loading components, the guard is applied in the routing configuration of the parent component, not in the routing configuration of the lazy loaded component.

回答3:

For those who still have this error - don't forget to include your AuthGuard service or class to main bootstrap function. And don't forget to import this service before bootstrap runs.

import { bootstrap } from '@angular/platform-browser-dynamic';

import { AppComponent } from './app.component';
import { AuthGuard } from './shared/auth.service';

bootstrap(AppComponent, [
  appRouterProviders,
  AuthGuard
]);

Angular 2 team did not mention this in main router docs, and it took couple of hours for me to figure it out.

回答4:

The answer is further down in the tutorial. See the file listings in the "Add the LoginComponent" topic under the "Component-less route:..." section in "Milestone 5: Route Guards". It shows AuthGuard and AuthService being imported and added to the providers array in login-routing.module.ts, and then that module being imported into app.module.ts.

login-routing.module.ts

  ...
    import { AuthGuard }            from './auth-guard.service';
    import { AuthService }          from './auth.service';
    ...
    @NgModule({
    ...
      providers: [
        AuthGuard,
        AuthService
      ]
    })
    export class LoginRoutingModule {}

app.module.ts

import { LoginRoutingModule }      from './login-routing.module';

@NgModule({
  imports: [
    ...
    LoginRoutingModule,
    ...    
  ],
  ...
  providers: [
    DialogService
  ],
  ...

回答5:

Actually, it was only a typo in an import...

I was typing

import { AuthGuard } from './../Authentification/auth.guard';

instead of

import { AuthGuard } from './../authentification/auth.guard';

making it not working but at the same time not displaying me any error...

(sadface)

回答6:

I encountered this issue when I was following a tutorial. I tried most of the answer here but not getting any success. Then I tried the silly way like putting the AuthGuard before the other services in the provider and it works.

// app.module.ts

 .. 
 providers: [
   AuthGuard,
   UserService,
   ProjectService
  ]

回答7:

Since you got the solution as it was due to syntax issue. I just wanted to share this info.

we need to provide the AuthGaudSerivce as provider in only that module that correspond to respective route. No need to provide in main module or root module as main module will automatically load all the given sub module.This helps in keeping the code modular and encapsulated.

for example, suppose we have below scenario

1. we have module m1
2. we have route m1r in module m1
3. route m1r has 2 route r1 and r2
4. we want to protect r1 using authGaurd
5. finally we have main module that is dependent on sub module m1 

Below is just prototype, not the actual code for understanding purpose

//m1.ts    
import {AuthGaurd} from './auth.gaurd.service'
import {m1r} from './m1r'
    @NgModule(
     imports: [m1r],
     providers: [AuthGaurd]
    )
    export class m1{
    }

//m1r.ts
import {AuthGaurd} from './auth.gaurd.service'
const authRoute = [
 {path: '/r1', component: 'authComponent', canActivate: [AuthGaurd]},
 {path: '/r2', component: 'other'}
]
export authRoute

//main.module.ts
import {m1} from ''
import {mainComponent} from ''
@NgModule({
  imports: [m1],
  bootstrap: [mainComponent]
  })
export class MainModule{}    

回答8:

import { Injectable } from '@angular/core';
import { Router, CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';

@Injectable()
export class AuthGuard implements CanActivate {

    constructor(private router: Router) { }

    canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) {
        if (localStorage.getItem('currentUser')) {
            // logged in so return true
            return true;
        }

        // not logged in so redirect to login page with the return url
        this.router.navigate(['/login'], { queryParams: { returnUrl: state.url }});
        return false;
    }
}

回答9:

Importing both HttpModule and HttpClientModule helped me.

import { HttpClientModule } from '@angular/common/http'; 
import { HttpModule } from '@angular/http';

回答10:

you can try import AuthGuard in provider of that module and then import it in the routing component-routing.module.ts file also

@NgModule({
providers: [
    AuthGuard
  ],})

回答11:

Try to add

@Injectable({ providedIn: 'root' }) no need to add to module provider.