Django Middleware Customization and Request Processing

Snippet

Django Middleware Customization and Request Processing

Django middleware processes requests/responses in a stacked pipeline. MiddlewareMixin provides compatibility between Django versions. process_request runs before view execution (return None to continue), while process_response runs after, allowing header modification. Middleware can short-circuit responses (returning HttpResponse stops the chain). Rate limiting via cache is a common pattern for API protection against abuse.

snippet.py
python
import json
from django.utils.deprecation import MiddlewareMixin
from django.contrib.auth.models import User
from django.core.cache import cache
 
class RequestLoggingMiddleware(MiddlewareMixin):
    def process_request(self, request):
        request.start_time = __import__('time').time()
        print(f'Request: {request.method} {request.path}')
        return None
 
    def process_response(self, request, response):
        duration = __import__('time').time() - request.start_time
        response['X-Response-Time'] = f'{duration:.3f}s'
        print(f'Completed in {duration:.3f}s - Status: {response.status_code}')
        return response
 
class RateLimitMiddleware(MiddlewareMixin):
    def process_request(self, request):
        if request.method == 'POST':
            ip = request.META.get('REMOTE_ADDR')
            cache_key = f'rate_limit:{ip}'
            hits = cache.get(cache_key, 0)
            
            if hits >= 10:
                return JsonResponse(
                    {'error': 'Rate limit exceeded'}, status=429
                )
            
            cache.set(cache_key, hits + 1, 60)
        return None

django

Breakdown

def process_request(self, request):

Executes before view resolution; returning None continues to next middleware or view

def process_response(self, request, response):

Executes after view renders; must return the response object

cache.set(cache_key, hits + 1, 60)

Cache stores hit count per IP for 60 seconds for rate limiting

return JsonResponse({'error': 'Rate limit exceeded'}, status=429)

Short-circuits request chain by returning response directly

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