POST request with json data using ironpython

I'm writing code in ironpython and I'm trying to send a http post request to the server with json in the request body. For this I use the C# method: HttpWebRequest. I know there are more advanced and simpler methods, but this is the way I have to work. My server is written in nodejs using express.

This is my client code:

import json
import clr
clr.AddReference('System')
clr.AddReference('System.IO')
clr.AddReference('System.Net')

from System import Uri
from System.Net import HttpWebRequest
from System.Net import HttpStatusCode
from System.IO import StreamReader, StreamWriter

def post(url, data):
    req = HttpWebRequest.Create(Uri(url))
    req.Method = "POST"
    req.ContentType = "application/json"

    json_data = json.dumps(data)

    reqStream = req.GetRequestStream()
    streamWriter = StreamWriter(reqStream)
    streamWriter.Write(json_data)
    streamWriter.Flush()
    streamWriter.Close()

    res = req.GetResponse()
    if res.StatusCode == HttpStatusCode.OK:
        responseStream = res.GetResponseStream()
        reader = StreamReader(responseStream)
        responseData = reader.ReadToEnd()
        return responseData

res = post('http://localhost:5050/hello', postData)
print(res)

And this is my server code:

const express = require("express");
let app = express();
const PORT = process.env.PORT || 5050;

app.post("/hello", (req, res) => {
    console.log("Hi!")
    console.log(req.body)
    res.json({"message": "Hello World"})
})

app.listen(PORT, () => {
    console.log(`Server listening on port ${PORT}`);
});

When I run my client code I get the server's response {"message": "Hello World"} in the output. On the server I of course see the log: "Hi!", but the output of the req.body is undefined.

I messed with it a lot and I really don't know what the problem is with my code, why can't I get the json that the client sends? Why am I getting undefined?

I'll be glad to receive your help.

you can use the bodyParser middleware to parse the request body.

you need just add this line:

app.use(express.json())

like this:

const express = require('express')
const PORT = process.env.PORT || 5050;

let app = express();
app.use(express.json()); // <-- here
    
app.post("/hello", (req, res) => {
    console.log("Hi!")
    console.log(req.body)
    res.json({"message": "Hello World"})
});
    
app.listen(PORT, () => {
    console.log(`Server listening on port ${PORT}`);
});