## Middleware

### Custom Middleware

```python
# middleware/active_user_middleware.py
import time
from django.utils.deprecation import MiddlewareMixin

class ActiveUserMiddleware(MiddlewareMixin):
    """Middleware to track active users."""

    def process_request(self, request):
        """Process incoming request."""
        if request.user.is_authenticated:
            # Update last active time
            request.user.last_active = timezone.now()
            request.user.save(update_fields=['last_active'])

class RequestLoggingMiddleware(MiddlewareMixin):
    """Middleware for logging requests."""

    def process_request(self, request):
        """Log request start time."""
        request.start_time = time.time()

    def process_response(self, request, response):
        """Log request duration."""
        if hasattr(request, 'start_time'):
            duration = time.time() - request.start_time
            logger.info(f'{request.method} {request.path} - {response.status_code} - {duration:.3f}s')
        return response
```