Angular 2 Error while fetching data from Django Rest API - django

Question

I'm new to Angular and I'm creating a test Application to accelerate my understanding of the topic. Recently I encountered a challenge to integrate Angular2(FrontEnd) with Django(Backend) by fetching the data using REST APIs.
File: 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));
}
}
File: 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);
}
}
REST API
# 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)
JSON I'm Expecting
[
{
"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"
}
]
Important
When I try to fetch data in the Component only, then I successfully get the result [See the commented code in libraries.components.ts]. But somehow it's not working in the Service, am I doing something wrong with Observables?
Note
This problem is very similar to Question here.
Big thanks to the community in advance :)

Answer 1

Few changes I've made:
Used HttpClient instead of Http. This allows me to remove .map() as HttpClien already returns the JSON (instead of the whole response).
Correct File: 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));
}
}