How Django Middleware Works

Middleware in Django is a lightweight, modular system used to handle the process of requests and responses. It consists of a Python class with methods for processing requests, handling responses, or executing before and after a view function.

The operation mechanism of Django middleware is as follows:

1. When a request arrives at a Django application, the middleware is called in order, with the middleware for the request-handling phase being executed first.
2. During the request handling process, each middleware can modify the request, log information, verify user identity, and perform other operations.
3. Before the request reaches the view function, all request handling middleware will be executed sequentially.
4. After the view function handles the request, the middleware in the response process will be executed in the opposite order, with the middleware in the response phase being executed last.
5. During the response handling process, each middleware can modify the response, add response headers, handle exceptions, and perform other operations.
6. Eventually, the response processed by all middleware will be returned to the client.

With middleware, developers can easily customize operations during the request and response handling process to meet more complex functional requirements.