Req.body does not get parsed and only undefined gets returned

Question

Yes, I've already looked at similar questions like this Express.js req.body undefined but it did not help me, and yes I've tried changing the code to a middleware.

My problem is that the passed XML is valid and everything is ok (I'm using Angular for Frontend), but my backend always delivers me an undefined variable req.body... I tried printing out console.log(req) and it always shows the body as an empty object.

I have the following code:

var testvar = req.body;
var req = http.request(options, function (res) {
    var chunks = [];
  
    res.on("data", function (chunk) {
      chunks.push(chunk);
    });
  
    res.on("end", function (chunk) {
      var body = Buffer.concat(chunks);
      console.log(body.toString());
    });
  
    res.on("error", function (error) {
      console.error(error);
    });
  });
  
  req.write(postData);
  
  req.end();
  console.log(testvar);

The code is implemented inside a app.post, which naturally contains req, res as usual. Options contain the IP, port etc, which is not relevant for solving this riddle.

Also: Once the post method is called, the error

TypeError: data should be a string, Buffer or Uint8Array

occurs in the backend.

Wait, is the response body undefined, or the request body from your front-end? — Take-Some-Bytes, Jul 13 '20 at 16:07
`req.body` is also defined into a variable BEFORE the code snippet so it should work in the (req,res) function, but for some reason it doesn't... — Munchkin, Jul 14 '20 at 10:08
Okay, let me reword my question.... Is the body that you received from the code that you showed here undefined? Or is it from an express route? — Take-Some-Bytes, Jul 14 '20 at 19:31
it's from `app.post` so I guess it would be an express route, yes. — Munchkin, Jul 15 '20 at 10:56

score 2 · Accepted Answer · answered Jul 16 '20 at 11:29

2

If native methods fail, try to install 'request' with node package manager.

Try to implement it in your function like this: var request = require('request');

You should now be able to access the body object via the request function as follows:

  request(options, function (error, request) {
    if (error) throw new Error(error);
    console.log(request.body);
    req.write(request.body);
    req.end();
    res.status(200).send(req.body);
  });

answered Jul 16 '20 at 11:29

crispyzlata

195
9

This actually works! Also the bonus points that the response is given back is fulfilled as well, any clue why the native approach fails? – Munchkin Jul 16 '20 at 11:31
2

depricated https://github.com/request/request/issues/3142 – x00 Jul 17 '20 at 20:11

score 0 · Answer 2 · answered Jul 13 '20 at 13:48

In angular try defining an interface for what you are receiving from the backend, so that when you create the observable, it knows what it is fetching from the backend. As you are saying that you have already parsed the information from the XML in the backend. this should work. Eg:

import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { ErrorprocessorService } from './errorprocessor.service';
import { Observable, Subject } from 'rxjs';
import { map } from 'rxjs/operators';

interface JWTResponse {
  success: boolean;
  message: string;
  user: any;
}

@Injectable({
  providedIn: 'root'
})

export class AuthService {

  constructor(private http: HttpClient, private errorProcessor: ErrorprocessorService) { }

  checkJWTtoken() {
    this.http.get<JWTResponse>('http://localhost:3000/auth/checkToken')
      .subscribe(res => {
        console.log('JWT Token Valid: ', res);
        this.sendUsername(res.user.username);
      }, err => {
        console.log('JWT Token Invalid: ', err);
        this.destroyUserCedentials();
      });
  }
}

My problem is clearly in the backend, since I'm getting a 500 error.. — Munchkin, Jul 14 '20 at 10:09
Apparently not. But I did already gave you a snippet in the question. — Munchkin, Jul 15 '20 at 13:49

score 0 · Answer 3 · answered Jul 15 '20 at 20:59

0

It seems you need to add an XML body parser.

You could try with body-parser-xml.

answered Jul 15 '20 at 20:59

Daniele Ricci

15,422
1
27
55

Thanks, I'll check it out. – Munchkin Jul 16 '20 at 07:30
didn't help, sorry – Munchkin Jul 16 '20 at 11:29
Just to clarify @Munchkin , in the code you posted is `testvar` the `null` variable you are trying to fix? – Daniele Ricci Jul 16 '20 at 11:43
yup, that's exactly the problem, but crispyzlata seems to already solved the issue by using a library, your answer should be natively implemented to be better – Munchkin Jul 16 '20 at 11:54

score 0 · Answer 4 · answered Jul 20 '20 at 17:55

0

You need xml-body-parser for this. The body-parser will only parse json, text etc but not the xml. So in your code, you might need to do something like,

var xmlparser = require('express-xml-bodyparser');

app.use(xmlparser());

answered Jul 20 '20 at 17:55

gaurav soni

206
1
10

Req.body does not get parsed and only undefined gets returned

4 Answers4