How to determine the sequence of request processing through middleware in the execution chain?

The sequence of request processing through middleware is determined by the order in which they are connected in the chain. In most web frameworks (for example, Django or Flask with extensions), middleware is called in the order they are registered. The first middleware receives the request first, then passes control to the next, and so on. When returning a response, the chain is processed in reverse order.

Example for Django:

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    # ... other middleware
]

Here, SecurityMiddleware processes the request first, then SessionMiddleware, and so on.