Node.js: Access JSON body of HTTP POST request with express

Question

I'm making an http post request to my express web server sending dummy data as json. It correctly receives the request and can send back a json object, but for some reason it can't manage to access the post request body.

I'm using this code for express:

const express = require('express');
const app = express();
const port = 3000;

app.post('/test', (req, res) => {
  console.log(req.body);
  res.json({"some": "thing"});
});

app.listen(port, () => {
  console.log(`Listening at http://localhost:${port}`)
});

And this is the code of the request:

const req = http.request({
    hostname: '127.0.0.1',
    port: 3000,
    path: '/test',
    method: 'POST',
    json: {
        url: "https://www.nothing.com",
        name: "hello"
    }
}, res => {
    console.log(`statusCode: ${res.statusCode}`)
  
    res.on('data', d => {
      process.stdout.write(d)
    })
  })
  
  req.on('error', error => {
    console.error(error)
  })
  
  req.end()

As you can see I'm running this locally. The client receives a status code 200 and the json {"some": "thing"} sent by the server, but the server gets "undefined" from req.body. I tried using:

headers: {
   'Content-Type': 'application/json'
}
body: JSON.stringify({
            url: "https://www.nothing.com",
            name: "hello"
        })

instead of json directly in the request options, but to no avail. I even tried using app.use(express.json()); as someone suggested.

What is the problem?

please add this line req.write(data); before req.end(); – Bunny May 26 '21 at 08:07 — Bunny, May 26 '21 at 08:07

score 1 · Accepted Answer · answered Jan 11 '21 at 21:10

Apparently the way I was doing the post request was not correct, I had to send the body in a separate line with req.write(), like this:

const http = require('http');
const data = JSON.stringify({ //<--- data to send as body
    url: "https://www.nothing.com",
    name: "hello"
});

const req = http.request({
    hostname: '127.0.0.1',
    port: 3000,
    path: '/test',
    method: 'POST',
    headers: {
        'Content-Type': 'application/json'
    }
}, res => {
    console.log(`statusCode: ${res.statusCode}`);
  
    res.on('data', d => {
      process.stdout.write(d);
    })
  })
  
  req.on('error', error => {
    console.error(error);
  })
  req.write(data); //<--- this line
  req.end();

score 0 · Answer 2 · 2021-01-11T18:11:03.387

0

You have to add body-parser middleware http://expressjs.com/en/resources/middleware/body-parser.html

req.body empty on posts

edited Jan 11 '21 at 18:11

answered Jan 11 '21 at 18:02

I read on another answer that body-parser is not needed from a certain version of express onward, you just need to use app.use(express.json()) as body parser. Either way I already used the module you suggested and it still didn't work. – shin Jan 11 '21 at 18:08
https://stackoverflow.com/questions/24543847/req-body-empty-on-posts – Jan 11 '21 at 18:11
body-parser is need but you don't need to install it separately – Jan 11 '21 at 18:13
yes, as I said I already used the parser as explained in your last link: app.use(express.json()); app.use(express.urlencoded()); but I still get an empty object. Have you tested my code? – shin Jan 11 '21 at 18:21

Node.js: Access JSON body of HTTP POST request with express

2 Answers2