What are the advantages of using middleware in FastAPI for request processing?

Middleware in FastAPI allows centralized processing of incoming requests and outgoing responses, which provides several advantages:

• Code reuse: you can implement common logic (e.g., logging, authentication, CORS handling) in one place, without duplicating it in each endpoint.
• Simplified architecture: separating cross-cutting concerns from business logic makes the code cleaner and more maintainable.
• Flexibility: middleware can be easily added, removed, or reordered.

Example of simple middleware for logging request processing time:

from fastapi import FastAPI, Request
import time

app = FastAPI()

@app.middleware("http")
async def log_request_time(request: Request, call_next):
    start_time = time.time()
    response = await call_next(request)
    process_time = time.time() - start_time
    print(f"Request {request.url.path} took {process_time:.4f} seconds")
    return response