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Custom Django Middleware for Request Timing

Django middleware hooks into the request/response cycle, allowing you to process requests before they reach the view and modify responses before they're sent back. This expert-level middleware measures request processing time using perf_counter for high-precision timing and attaches the result as a custom header. The process_exception hook handles errors globally across all views.

snippet.py

python

import time
from django.http import JsonResponse
 
class TimingMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response
 
    def __call__(self, request):
        start = time.perf_counter()
        response = self.get_response(request)
        duration = time.perf_counter() - start
        response['X-Request-Duration'] = f'{duration:.4f}s'
        return response
 
    def process_exception(self, request, exception):
        return JsonResponse({'error': str(exception)}, status=500)

django

Breakdown

import time

Imports the time module for high-precision timing functions

class TimingMiddleware:

Defines a middleware class that follows Django's middleware pattern

def __init__(self, get_response):

Django calls this once when the server starts to initialize the middleware

def __call__(self, request):

Django invokes this for each request, passing the request object

start = time.perf_counter()

perf_counter provides the most accurate monotonic timer available

response['X-Request-Duration'] = f'{duration:.4f}s'

Attaches timing data as a custom HTTP header for monitoring

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Custom Django Middleware for Request Timing

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