Django Middleware

Introduction

Middleware is a framework of hooks into Django's request/response processing.

Built-in Middleware

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
]

Custom Middleware

class RequestLoggerMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response
    
    def __call__(self, request):
        # Before view
        print(f"Request: {request.path}")
        
        response = self.get_response(request)
        
        # After view
        print(f"Response: {response.status_code}")
        return response

Method Hooks

class ProcessMiddleware:
    def process_request(self, request):
        # Before routing
        pass
    
    def process_view(self, request, view_func, view_args, view_kwargs):
        # Before view call
        pass
    
    def process_response(self, request, response):
        # After view
        return response
    
    def process_exception(self, request, exception):
        # On exception
        return None  # Or HttpResponse

Practice Problems

1. Log all requests
2. Track user sessions
3. Add CORS headers
4. Rate limiting middleware
5. Authentication middleware