FastAPI - decorator vs Depends equivalance

fastapi-decorator-vs-depends.py

'''
The same functionality expressed as decorators and Depends
'''

from fastapi import FastAPI, Request, Depends
import logging

app = FastAPI()

# Set up logging
logging.basicConfig(level=logging.INFO)

# Dependency 1: Log the request method
async def log_request_method(request: Request):
    logging.info(f"Request Method: {request.method}")

# Dependency 2: Log the request URL
async def log_request_url(request: Request):
    logging.info(f"Request URL: {request.url}")

@app.get("/data")
async def get_data(
    user_id: int,
    method: None = Depends(log_request_method),  # Injecting the logging dependency
    url: None = Depends(log_request_url)          # Injecting the logging dependency
):
    # Sample response
    return {"message": "Data retrieved successfully", "user_id": user_id}

# To run the application, use the command:
# uvicorn filename:app --reload


'''
Is equivalent to this 
'''

from fastapi import FastAPI, Request, HTTPException
from functools import wraps

app = FastAPI()

# Custom Decorator 1: Log the request method
def log_request_method(func):
    @wraps(func)
    async def wrapper(request: Request, *args, **kwargs):
        print(f"Request Method: {request.method}")
        return await func(request, *args, **kwargs)
    return wrapper

# Custom Decorator 2: Log the request URL
def log_request_url(func):
    @wraps(func)
    async def wrapper(request: Request, *args, **kwargs):
        print(f"Request URL: {request.url}")
        return await func(request, *args, **kwargs)
    return wrapper

@app.get("/data")
@log_request_method
@log_request_url
async def get_data(request: Request, user_id: int):
    # Sample response
    return {"message": "Data retrieved successfully", "user_id": user_id}

# To run the application, use the command:
# uvicorn filename:app --reload