“No provider for AuthGuard!” using CanActivate in Angular 2

Question

EDIT : Obviously this is outdated, now you provide your guard at the providers array in an NgModule.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

Answer 1

This happened to me when I had setup my Routes incorrectly:

WRONG

const routes: Routes = 
[
  { 
    path: 'my-path', 
    component: MyComponent, 
    resolve: { myList: MyListResolver, canActivate: [ AuthenticationGuard ] } 
  },
];

Note that in this case canActivate was accidentally made a part of the resolve object.

CORRECT

const routes: Routes = 
[
  { 
     path: 'my-path', 
     component: MyComponent, 
     resolve: { myList: MyListResolver }, 
     canActivate: [ AuthenticationGuard ] 
  },
];

Answer 2

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;
    }
}

Answer 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.

Answer 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
  ],
  ...

Answer 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)

Answer 6

Importing both HttpModule and HttpClientModule helped me.

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