在中间件上下文中获取starlette请求主体

Question

我有这样的想法

class RequestContext(BaseHTTPMiddleware):
    async def dispatch(self, request: Request, call_next: RequestResponseEndpoint):
        request_id = request_ctx.set(str(uuid4()))  # generate uuid to request
        body = await request.body()
        if body:
            logger.info(...)  # log request with body
        else:
            logger.info(...)  # log request without body
 
        response = await call_next(request)
        response.headers['X-Request-ID'] = request_ctx.get()
        logger.info("%s" % (response.status_code))
        request_ctx.reset(request_id)

        return response

因此body = await request.body()行冻结了所有具有body的请求，我从所有请求中获得了504个请求。在这种情况下，如何安全地阅读请求正文？我只想记录请求参数

Answer 1

如果您仍然想使用BaseHTTP，我最近遇到了这个问题，并提出了一个解决方案：

中间件代码

from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request
import json
from .async_iterator_wrapper import async_iterator_wrapper as aiwrap

class some_middleware(BaseHTTPMiddleware):
   async def dispatch(self, request:Request, call_next:RequestResponseEndpoint):
      #              
      # DO WHATEVER YOU TO DO HERE
      #             -
      
      response = await call_next(request)

      # Consuming FastAPI response and grabbing body here
      resp_body = [section async for section in response.__dict__['body_iterator']]
      # Repairing FastAPI response
      response.__setattr__('body_iterator', aiwrap(resp_body)

      # Formatting response body for logging
      try:
         resp_body = json.loads(resp_body[0].decode())
      except:
         resp_body = str(resp_body)

来自TypeError from Python 3 async for loop

class async_iterator_wrapper:
    def __init__(self, obj):
        self._it = iter(obj)
    def __aiter__(self):
        return self
    async def __anext__(self):
        try:
            value = next(self._it)
        except StopIteration:
            raise StopAsyncIteration
        return value

我真的希望这能帮助别人！我发现这对日志记录非常有用

非常感谢@Eddified参加aiwrap课程

Answer 2

我不会创建一个继承自BaseHTTPMiddleware的中间件，因为它有一些issues，FastAPI为您提供了创建自己的路由器的机会，根据我的经验，这种方法更好

from fastapi import APIRouter, FastAPI, Request, Response, Body
from fastapi.routing import APIRoute

from typing import Callable, List
from uuid import uuid4


class ContextIncludedRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request_id = str(uuid4())
            response: Response = await original_route_handler(request)

            if await request.body():
                print(await request.body())

            response.headers["Request-ID"] = request_id
            return response

        return custom_route_handler


app = FastAPI()
router = APIRouter(route_class=ContextIncludedRoute)


@router.post("/context")
async def non_default_router(bod: List[str] = Body(...)):
    return bod


app.include_router(router)

一切正常

b'["string"]'
INFO:     127.0.0.1:49784 - "POST /context HTTP/1.1" 200 OK