user.service.ts

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Rx';
import { Headers, RequestOptions } from '@angular/http';

import { LocalStorageService } from 'angular-2-local-storage';

import 'rxjs/add/observable/from';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/toPromise';

import { User } from '../models/user';

@Injectable()
export class UserService {
    url = "http://localhost:3000/api/users";
    constructor(private http:Http, private localStorageService: LocalStorageService) { }

    login(user) {
      let headers = new Headers({ 'Content-Type': 'application/json' });
      let options = new RequestOptions({ headers: headers });
      let body = JSON.stringify(user);
      return this.http.post('/login', body, options ).map((res: Response) => res.json());
    }

    createUser(user) {
      let headers = new Headers({ 'Content-Type': 'application/json' });
      let options = new RequestOptions({ headers: headers });
      let body = JSON.stringify(user);
      console.log(body);
      return this.http.post('/api/users/', body, options ).map((res: Response) => res.json());
    }

    createUserFromTable(user) {
      let headers = new Headers({ 'Content-Type': 'application/json' });
      let options = new RequestOptions({ headers: headers });
      let body = JSON.stringify(user);
      console.log(body);
      return this.http.post('/api/users/', body, options ).map((res: Response) => res.json());
    }

    updateUser(user) {
      alert(user.name + " : " + user.role);
      let headers = new Headers({ 'Content-Type': 'application/json' });
      let options = new RequestOptions({ headers: headers });
      user.name = "user";
      user.password = "user";
      user.role = "admin";
      console.log("USER="+JSON.stringify(user));
      let body = JSON.stringify(user);
      return this.http.put('/api/users/'+user.id, body, options ).map((res: Response) => res.json());
    }

    deleteUser(user_id) {
        return this.http.delete('/api/users/' + user_id);
    }

    getUsersWithPromise(): Promise<User[]> {
        return this.http.get(this.url).toPromise()
                     .then(this.extractData)
                     .catch(this.handleError);
    }

    getUserById(user_id): Promise<User> {
        return this.http.get(this.url + "/" + user_id).toPromise()
                   .then(this.extractData)
                   .catch(this.handleError);
    }

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

    private handleError (error: Response | any) {
          console.error(error.message || error);
          return Promise.reject(error.message || error);
    }

}