Python 瓶子没有来自 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

Answer 1

print() only goes to the terminal, and therefore conflicts with your access logs. It doesn't return an HTTP response.

If you want to echo back the request JSON to JS, then you want

@post('/update_game')
def update_game():
    return request.json

And then parse the body from a JS future from fetch()

Otherwise, you wanta Response object where you can set status codes, such as 201.

Adding Content-Type: application/json from your JS wouldn't hurt.

Answer 2

The correct header would be Content-Type: application/json not "contentType: application/JSON". Can you please try the correct header?

Answer 3

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

Answer 4

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)