从 Django Rest API 获取数据时出现角度 2 错误

Question

我是 Angular 的新手，我正在创建一个测试应用程序来加速我对这个主题的理解。最近，我遇到了一个挑战，通过使用REST API获取数据来将Angular2(FrontEnd(与Django(Backend(集成。

文件： library.service.ts

import 'rxjs/add/operator/map';
import { Observable } from 'rxjs/Rx';
import { Injectable } from '@angular/core';
import { Headers, Http, Response } from '@angular/http';
// Project Modules
import { Library } from '../models';

@Injectable()
export class LibraryService {
private librariesUrl = 'http://127.0.0.1:8000/api/library/create-library/';
constructor(private http: Http) { }
private headers = new Headers({'Content-Type': 'application/json'});
private extractData(res: Response) {
return res.json();
}
private handleError (error: any) {
return Observable.throw(error.message || 'Server error');
}
getAll(): Observable<Library[]> {
return this.http.get(this.librariesUrl, {headers: this.headers})
.map((res) => this.extractData(res.json())).catch((err) => this.handleError(err));
}
}

文件： libraries.component.ts

import { Component, OnInit} from '@angular/core';
import {HttpClient} from '@angular/common/http';
// Project Modules
import { Library } from '../models';
import { LibraryService } from './library.service';
@Component({
selector: 'app-libraries',
templateUrl: './libraries.component.html',
styleUrls: ['./libraries.component.css'],
})
export class LibrariesComponent implements OnInit {
libraries: Library[];
personalLibraries: Library[];
collaborativeLibraries: Library[];
constructor(private libraryService: LibraryService, private http: HttpClient) { }
ngOnInit(): void {
/*this.http.get('http://127.0.0.1:8000/api/library/create-library/').subscribe((data: Library[]) => {
console.log(data);
this.personalLibraries = data;
});*/
this.libraryService.getAll().subscribe(response => this.personalLibraries = response);
}
}

休息接口

# Django Modules
from django.shortcuts import get_object_or_404
# REST Modules
from rest_framework import status
from rest_framework.response import Response
from rest_framework.views import APIView
from rest_framework.decorators import api_view, authentication_classes, permission_classes
# Project Modules
from .models import Resource, ResourceUserAssociation, Collection, Library
from mysite.utils import get_value_or_404, get_value_or_default, get_boolean
from .serializers import LibrarySerializer, CollectionSerializer

# TODO: Check user authentication here
class CreatorLibraryAPI(APIView):
def get(self, request, format=None):
# slug = get_value_or_404(request.GET, 'slug')
lib_object = Library.objects.filter(type='personal')
sdata = LibrarySerializer(lib_object, many=True).data
return Response(sdata, status=status.HTTP_200_OK)

我期待的 JSON

[
{
"slug": "tech-stack",
"title": "Technology Stack",
"description": "Library of resources related to Technology",
"type": "personal"
},
{
"slug": "biz-stack",
"title": "Technology Stack",
"description": "Library of resources related to Business",
"type": "personal"
},
{
"slug": "design-stack",
"title": "Design Stack",
"description": "Library of resources related to Design",
"type": "personal"
}
]

重要提示当我尝试仅在组件中获取数据时，我成功获得了结果 [请参阅 libraries.components.ts 中的注释代码]。但不知何故它在服务中不起作用，我对可观察量做错了吗？

注意：此问题与此处的问题非常相似。

提前非常感谢社区:)

Answer 1

我做了一些更改：使用HttpClient而不是Http。这允许我删除 .map((，因为 HttpClien 已经返回了 JSON(而不是整个响应(。

正确的文件：library.service.ts

import 'rxjs/add/operator/map';
import { Observable } from 'rxjs/Rx';
import { Injectable } from '@angular/core';
import { Headers } from '@angular/http';
import {HttpClient} from '@angular/common/http';
// Project Modules
import { Library } from '../models';

@Injectable()
export class LibraryService {
private librariesUrl = 'http://127.0.0.1:8000/api/library/create-library/';
constructor(private http: HttpClient) { }
private headers = new Headers({'Content-Type': 'application/json'});
private handleError (error: any) {
console.log('---------- CATCH ERROR ----------');
return Observable.throw(error.message || 'this is some random server error');
}
getAll(): Observable<Library[]> {
return this.http.get(this.librariesUrl).catch((err) => this.handleError(err));
}
}