FastAPI access Context

[sidjakinsboriss]

Is there currently a way to access the RabbitMessage in the handler when using the FastAPI plugin? If I do it like in the code snippet below, I get some Pydantic validation errors. I need it to manually acknowledge or reject messages in certain cases.

from faststream.rabbit.fastapi import RabbitRouter
from faststream.rabbit.annotations import RabbitMessage

router = RabbitRouter()

@router.subscriber("test")
async def handler(msg: str, message: RabbitMessage):
    await message.nack()

[Lancetnik]

@sidjakinsboriss we already have the Issue to make FastStream Context FastAPI-compatible

But, for now you can get access to it manually from the context object:

from faststream import context
from faststream.rabbit import RabbitMessage

@router.subscriber("test")
async def handler(msg_body):
    msg: RabbitMessage = context.get_local("message")
    await msg.ack()

Also, if you like the original way to get access to raw message, you can use the following snippet - it works the same way

from typing import Annotated

from fastapi import Depends
from faststream.rabbit.message import RabbitMessage as RawRabbitMessage

def get_msg():
    return context.get_local("message")

RabbitMessage = Annotated[RawRabbitMessage, Depends(get_msg)]

@router.subscriber("test")
async def handler(msg_body, msg: RabbitMessage):
    await msg.ack()

Btw, all FastStream AckMessage, NackMessage, etc exceptions should works fine with FastAPI too. So you can just raise them in your handler to ack/nack message manually.

[sidjakinsboriss]

That doesn't really work, since the message context is only set when is_apply_types is True:

if self._is_apply_types:
    process_f = set_message_context(process_f)

However, when using a RabbitRouter (or any StreamRouter), it's set to False

self.broker = self.broker_class(
            *connection_args,
            apply_types=False,
            tags=asyncapi_tags,
            **connection_kwars,
        )

I can overwrite it by saying router._is_apply_types=True, but that seems hacky

[Lancetnik]

@sidjakinsboriss indeed, I just forgot about this condition. It was removed with 0.3.5, so you can use the examples below

[Lancetnik]

@sidjakinsboriss was Depends solution helpful for u?

[sidjakinsboriss]

Yes it was, thanks for the suggestion!

[Lancetnik]

Btw, this idea inspired me to add FastAPI-compatible Context feature with #1060