• • 此问题在此处已有答案**：

（13个答案）
Get raw POST body in Python Flask regardless of Content-Type header（4个答案）
3天前关闭。
最小示例：

#!/usr/bin/env python3

import json
from dataclasses import dataclass

from flask import Flask, request, make_response
from flask_restful import Resource, Api

@dataclass
class Foo:
    bar: int

class WebController(Resource):
    def __init__(self, factor) -> None:
        self._factor = factor

    def post(self):
        foo = Foo(**json.loads(request.data))
        return make_response(str(self._factor * foo.bar), 200)

def main():
    app = Flask(__name__)
    api = Api(app)
    api.add_resource(WebController, "/json_post_endpoint", resource_class_kwargs={"factor": 2})
    app.run(port=8080)

if __name__ == "__main__":
    main()

运行它，然后发送一个不带标头的curl：

curl -X POST --url http://localhost:8080/json_post_endpoint --data '{ "bar": 42 }'
{"message": "Internal Server Error"}

日志：

[2023-01-06 10:34:23,616] ERROR in app: Exception on /json_post_endpoint [POST]
Traceback (most recent call last):
  File "/home/tobias/.local/lib/python3.10/site-packages/flask/app.py", line 1820, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/tobias/.local/lib/python3.10/site-packages/flask/app.py", line 1796, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/home/tobias/.local/lib/python3.10/site-packages/flask_restful/__init__.py", line 467, in wrapper
    resp = resource(*args, **kwargs)
  File "/home/tobias/.local/lib/python3.10/site-packages/flask/views.py", line 107, in view
    return current_app.ensure_sync(self.dispatch_request)(**kwargs)
  File "/home/tobias/.local/lib/python3.10/site-packages/flask_restful/__init__.py", line 582, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/home/tobias/Documents/main.py", line 20, in post
    foo = Foo(**json.loads(request.data))
  File "/usr/lib/python3.10/json/__init__.py", line 346, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.10/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.10/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

但是有了标头，curl就可以了：

curl -X POST --url http://localhost:8080/json_post_endpoint --header 'Content-Type: application/json' --data '{ "bar": 42 }'
84

向请求添加标头会使服务器的行为发生什么变化？