canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> | boolean {

    if (state.url !== '/login' && !this.authService.isLoggedIn()) {
        this.router.navigate(['/login']);
        return false;
    }

    return true;
}

import { Injectable }     from '@angular/core';
import { Http, Response, Headers } from '@angular/http';
import { Router } from '@angular/router'
import { Observable }     from 'rxjs/Rx';
import { IMenu } from '../interfaces/menu';
import { AppSettings } from '../AppSettings';

@Injectable()
export class LoginService{
    private _baseUrl:string = AppSettings.API_ENDPOINT;
    private _loggedIn = false;

    constructor(private _http : Http, private  _router : Router){
        this._loggedIn = !!localStorage.getItem('auth_token')
        && !!localStorage.getItem('role')
        && !!localStorage.getItem('menu')
    }


    //Post function to send username and password to authorize in the server
    login(Username:string, Password:string) : Observable<IMenu[]>{
        let headers = new Headers();
        headers.append("Authorization", "Basic " + btoa(Username + ":" + Password));
        headers.append("Content-Type", "application/x-www-form-urlencoded");
        return this._http.post(this._baseUrl+"auth/login", " " , {headers: headers}  ).delay(2000).
            map((response: Response) => {
                <IMenu[]>response.json();
                localStorage.setItem("menu",JSON.stringify(<IMenu[]>response.json()));
                localStorage.setItem("auth_token", response.headers.get("Token"));
                localStorage.setItem("role", response.headers.get("Role"));
            }).catch(this.handleError);
    }

    logout() {
        localStorage.removeItem("auth_token");
        localStorage.removeItem("menu");
        localStorage.removeItem("role");
        this._router.navigate(['/login']);
        return false;
    }

    isLoggedIn() {
        return this._loggedIn;
    }

    private handleError(error: Response){
        return Observable.throw(error.json().error || 'Server Error!');
    }
}