How do you create and integrate your own middleware layer into an application?

In Python, creating custom middleware is usually associated with web frameworks such as Flask or Django. Middleware is a component that processes requests and/or responses between the client and the main application.

Example of simple middleware in Flask:

from flask import Flask, request

app = Flask(__name__)

@app.before_request
def before_request_func():
    print(f"Request received: {request.method} {request.path}")

@app.route('/')
def index():
    return "Hello, World!"

if __name__ == '__main__':
    app.run()

Here, the before_request_func function runs before processing each request — this is an example of an intermediate layer.

In more complex cases, middleware can modify requests, check authorization, log data, or handle errors. In Django, middleware is implemented as classes with __call__ methods or process_request and process_response methods.