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Unable to get request body in custom request formatter when using FastAPI #84
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i would suggest u extend logging.Formatter for maximum flexibility, something like that
json-logging-python/json_logging/__init__.py
Line 267 in 8d6c1dd
Yes, I'm aware of them (and I've used them before with Flask). But the methods inside of this class (
formatand_format_log_object) are notasync, so I can't write something likerequest_body = await request.body(), which is the only way to get the request body in FastAPI.@vstrimaitis is not really familiar with async await syntax. But will do some experiment once have time
@vstrimaitis @bobbui I have the same issue. Have you found a solution?
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on Nov 4, 2022 My solution:
with this patch I can execute:
from json_logging.dto import DefaultRequestResponseDTO ... class async_iterator_wrapper: """Class to create async iterator""" 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 class CustomRequestResponseDTO(DefaultRequestResponseDTO): async def async_on_request_complete(self, response): super(CustomRequestResponseDTO, self).on_request_complete(response) self['request'] = '{} {}'.format(self._request.method, self._request.url) resp_body = [section async for section in self._response.body_iterator] self['response_body'] = b'\n'.join(resp_body).decode() self._response.body_iterator = async_iterator_wrapper(resp_body)Hi @stephane-klein! I ended up making a custom middleware class which extends
BaseHTTPMiddlewareand monkeypatchedjson_logging.framework.fastapi.implementation.JSONLoggingASGIMiddlewareto point to this new class. The actual implementation of the class is exactly likeJSONLoggingASGIMiddlewareexcept it additionally extracts the request body from therequestobject and makes it available as an additional entry in theextradict. This allowed me to then define the custom request formatter class in a standard way and just extract the request body from therecordobject.This is obviously not a clean solution in any sense, but it ended up working for me back when I needed it and the implementation has stayed the same since then 😅
I'm interested in getting the request body in a custom request formatter when using FastAPI. However,
request.body()returns a coroutine and therefore requires theawaitkeyword, but the_format_log_objectmethod is notasync. My custom formatter looks something like this:Such an approach works in frameworks like Flask, where you don't have to use
awaitto get the body, but fails for FastAPI. Do you have any suggestions on how to work around this?