Angular2 - Redirect to calling url after successful login

Question

I have my application up and running with Angular 2.1.0. The routes are protected via router Guards, canActivate.

When pointing the browser to a protected area like "localhost:8080/customers" I get redirected to my login page just like expected.

But after a successful login, I would like to be redirected back to calling URL ("/customers" in this case).

The code for handling the login looks like this

login(event, username, password) {
  event.preventDefault();
  var success = this.loginService.login(username, password);
  if (success) {
    console.log(this.router);
    this.router.navigate(['']);
  } else {
    console.log("Login failed, display error to user");
  }
}

The problem is, I don't know how to get a hold of the calling url from inside the login method.

I did find a question (and answer) regarding this but couldn't really make any sense of it. Angular2 Redirect After Login

Answer 1

There's a tutorial in the Angular Docs, Milestone 5: Route guards. One possible way to achieve this is by using your AuthGuard to check for your login status and store the url on your AuthService.

AuthGuard

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

@Injectable()
export class AuthGuard implements CanActivate {
  constructor(private authService: AuthService, private router: Router) {}

  canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): boolean {
    let url: string = state.url;

    return this.checkLogin(url);
  }

  checkLogin(url: string): boolean {
    if (this.authService.isLoggedIn) { return true; }

    // Store the attempted URL for redirecting
    this.authService.redirectUrl = url;

    // Navigate to the login page with extras
    this.router.navigate(['/login']);
    return false;
  }
}

AuthService or your LoginService

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Router } from '@angular/router';

@Injectable()
export class AuthService {
  isLoggedIn: boolean = false;    
  // store the URL so we can redirect after logging in
  public redirectUrl: string;

  constructor (
   private http: Http,
   private router: Router
  ) {}

  login(username, password): Observable<boolean> {
    const body = {
      username,
      password
    };
    return this.http.post('api/login', JSON.stringify(body)).map((res: Response) => {
      // do whatever with your response
      this.isLoggedIn = true;
      if (this.redirectUrl) {
        this.router.navigate([this.redirectUrl]);
        this.redirectUrl = null;
      }
    }
  }

  logout(): void {
    this.isLoggedIn = false;
  }
}

I think this will give an idea how things work, of course you probably need to adapt to your code

Answer 2

This code will handle your request:

export class AuthGuard implements CanActivate {
  constructor(private authService: AuthService,
              private router: Router) {
  }

  canActivate(next: ActivatedRouteSnapshot,
              state: RouterStateSnapshot): Observable<boolean> {
    return this.authService.isVerified
      .take(1)
      .map((isVerified: boolean) => {
        if (!isVerified) {
          this.router.navigate(['/login'], {queryParams: {returnUrl: state.url}});
          return false;
          // return true;
        }
        return true;
      });
  }
}

but be aware that the URL params will not pass with the URL!!

You can find a nice tutorial here : http://jasonwatmore.com/post/2016/12/08/angular-2-redirect-to-previous-url-after-login-with-auth-guard

Answer 3

The answers I saw were correct. But the best way to answer your question is returnUrl. like this:

export class AuthGuardService implements CanActivate {

  constructor(private auth: AuthenticationService, private router: Router) { }

  canActivate(next: ActivatedRouteSnapshot,
    _state: import('@angular/router').RouterStateSnapshot): Observable<boolean> | Promise<boolean> | boolean {
    let isLoggedIn = false;
    const idToken = next && next.queryParamMap.get('id_token');
    try {
      const expiresAt = idToken && JSON.parse(window.atob(idToken.split('.')[1])).exp * 1000;
      if (idToken && expiresAt) {
        isLoggedIn = true;
        localStorage.setItem('id_token', idToken);
        localStorage.setItem('expires_at', String(expiresAt));
      } else {
        isLoggedIn = this.auth.isLoggedIn();
      }
    } catch (e) {
      console.error(e);
      isLoggedIn = this.auth.isLoggedIn();
    }
    if (!isLoggedIn) {
      //this section is important for you:
      this.router.navigate(['/login'], { queryParams: { returnUrl: _state.url }});
    }
    return isLoggedIn;
  }
}

This navigate create a url with returnUrl like a param, now you can read returnUrl from param.

GoodLuck.