StackOverflow 64497615

.gitignore

venv/
*.pyc

main.py

from fastapi import FastAPI, Request
from pydantic import BaseModel


class SampleModel(BaseModel):
    name: str
    age: int


app = FastAPI()

def do_something_with_request_object(request: Request):
    print(request)

def auth_required(handler):
    async def wrapper(request: Request, *args, **kwargs):
        do_something_with_request_object(request)
        return await handler(*args, **kwargs)

    # Fix signature of wrapper
    import inspect
    wrapper.__signature__ = inspect.Signature(
        parameters = [
            # Use all parameters from handler
            *inspect.signature(handler).parameters.values(),

            # Skip *args and **kwargs from wrapper parameters:
            *filter(
                lambda p: p.kind not in (inspect.Parameter.VAR_POSITIONAL, inspect.Parameter.VAR_KEYWORD),
                inspect.signature(wrapper).parameters.values()
            )
        ],
        return_annotation = inspect.signature(handler).return_annotation,
    )

    return wrapper


@app.post("/")
@auth_required # Custom decorator
async def root(payload: SampleModel):
    return {"message": f"Hello {payload.name}, {payload.age} years old!"}

Makefile

venv/:
	python3 -m venv venv
	. venv/bin/activate && \
		pip install --upgrade pip && \
		pip install uvicorn pydantic fastapi

.PHONY: run
run: venv/
	. venv/bin/activate && \
		uvicorn --host 0.0.0.0 --port 8000 main:app

.PHONY: clean
clean:
	rm -rf venv/

test.http

POST http://localhost:8000/

{
    "name": "Douglas Adams",
    "age": 42
}