Python Bottle is None from React JSON

Question

I have this in React:

const payload = {
    x : x,
    y : y
}

fetch("http://localhost:8080/update_game", {
    method: "POST",
    body: JSON.stringify(payload)})

And this in Python:

@post('/update_game')
def update_game():
    req = request.json
    print(req);

I keep getting:

None
127.0.0.1 - - [24/Jan/2022 14:06:36] "POST /update_game HTTP/1.1" 200 0

I don't see what I would be doing different than all of the other examples I've been finding. payload successfully logs in the console. I have CORS set up and working correctly in Python. I also tried adding contentType: application/JSON to the react side. I don't see what I could be doing wrong here.

edit for clarity: I'm attempting to print out the json response in the terminal on the python side. I simply want to see that this response is going through.

I discovered this little bit, that does show something, but is not correct:

@post('/update_game')
def update_game():
    req = request.forms
    print(dir(req))
    print(dict(req))
    print(req)

the ouput:

{'{"x":"0","y":"6"}': ''}

And I also have this:

def update_game():
   req = request.headers['Content-Type']
   # print(dir(req))
   # print(dict(req))
   print(req)

output:

text/plain;charset=UTF-8

I'm pretty sure that should be application/JSON

score 0 · Answer 1 · answered Jan 24 '22 at 23:15

Starting from scratch...

$ python3 -m venv venv
$ source venv/bin/activate
$ python -m pip install -U bottle

Create app.py

from bottle import post, request, run

@post('/echo')
def echo():
    data = request.json
    print(type(data))
    return data  # example to return the input

run(host='localhost', port=8080, debug=True)

Run python app.py

From a new terminal, I pass the Content-Type along with a payload to return

$ curl -H 'Content-Type: application/json' -d'{"x": 2, "y":4}' http://localhost:8080/echo
{"x": 2, "y": 4}

In the server logs, I see

<class 'dict'>
127.0.0.1 - - [24/Jan/2022 17:13:38] "POST /echo HTTP/1.1" 200 16

See this post for properly sending JSON from Javascript without it being text/plain - Setting Content-Type in fetch request not working

score 0 · Answer 2 · answered Jan 24 '22 at 23:22

I found one solution. Hopefully this one helps whoever is having the same issues.

import json
import io


@post('/update_game')
def update_game():
    encoding = "UTF-8"
    req = json.load(io.TextIOWrapper(request.body, encoding=encoding))
    print(req)

Python Bottle is None from React JSON

2 Answers2