@Injectable()
export class AuthService {
  private url ='http://localhost:3000/user/1';
  constructor(private http: Http){}
  isLoggedIn: boolean = false;
  user : User;
  errorMessage:any;


  login(username:string, password:string) {
 this.getUser(username, password).subscribe((user)=>{
    if(user.login===username && password===user.password){
      this.isLoggedIn=true;
    }
 })
}

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

  getUser(username:string, password:string): Observable<User>{
       return (this.http.get(this.url)
            .map(this.extractData)
            .catch(this.handleError))

    }

    private extractData(res: Response){
        let body = res.json();
        return body || {};
    }

    private handleError (error: Response | any) {
    // In a real world app, you might use a remote logging infrastructure
    let errMsg: string;
    if (error instanceof Response) {
      const body = error.json() || '';
      const err = body.error || JSON.stringify(body);
      errMsg = `${error.status} - ${error.statusText || ''} ${err}`;
    } else {
      errMsg = error.message ? error.message : error.toString();
    }
    console.error(errMsg);
    return Observable.throw(errMsg);
  }
}

public Dologin() {
    this.message = 'Trying to log in ...';

  this.authService.login(this.model.username, this.model.password)
  .subscribe(() => {
  this.setMessage();
  if (this.authService.isLoggedIn) {

    let redirect = '/main';

    let navigationExtras: NavigationExtras = {
      preserveQueryParams: true,
      preserveFragment: true
    };

    // Redirect the user
    this.router.navigate([redirect], navigationExtras);
  }
});
 }