How do I POST JSON in Angular 2? - rest

Question

I don't understand what I am doing wrong, my server returns "undefined" when I try to get the json.
POST(url, data) {
var headers = new Headers(), authtoken = localStorage.getItem('authtoken');
headers.append("Content-Type", 'application/json');
if (authtoken) {
headers.append("Authorization", 'Token ' + authtoken)
}
headers.append("Accept", 'application/json');
var requestoptions = new RequestOptions({
method: RequestMethod.Post,
url: this.apiURL + url,
headers: headers,
body: data
})
return this.http.request(new Request(requestoptions))
.map((res: Response) => {
if (res) {
return { status: res.status, json: res.json() }
}
});
}
And my function:
login(username, password) {
this.POST('login/', {test: 'test'}).subscribe(data => {
console.log(data)
})
}
When I try this, the request body looks like this:
So instead of sending actual json, it just sends "[object Object]".
Instead of "Request payload" it should be "JSON". What am I doing wrong?

Answer 1

I have been looking for a visual answer to the question of posting json data in Angular for a while, to no avail. Now that I eventually have something working, let's share:
Inlined
Let's assume you expect a json response body of type T.
const options = {headers: {'Content-Type': 'application/json'}};
this.http.post<T>(url, JSON.stringify(data), options).subscribe(
(t: T) => console.info(JSON.stringify(t))
);
Official doc
Extendable class
import { HttpClient, HttpHeaders } from '#angular/common/http';
export class MyHttpService {
constructor(protected http: HttpClient) {}
headers = new HttpHeaders({
'Content-Type': 'application/json'
});
postJson<T>(url: string, data: any): Observable<T> {
return this.http.post<T>(
url,
JSON.stringify(data),
{headers: this.headers}
)
}
The gist
In the beginning I missed this sort of 'nested' way to pass in the content-type:
{headers:{'Content-Type': 'application/json'}}

Answer 2

You need to stringify the payload
var requestoptions = new RequestOptions({
method: RequestMethod.Post,
url: this.apiURL + url,
headers: headers,
body: JSON.stringify(data)
})

Answer 3

The header should be
'Content-Type': 'application/json'
and
body: data
should be
body: JSON.stringify(data);