Django middleware to collect basic statistics and show on a template

index.html

{% if request.user.is_superuser %}
  <div class="p-4 bg-gray-100">
    <div class="font-bold">
      DEBUG-O-MATIC
    </div>

    <!-- DEBUG STATS -->

    <div class="pt-2 font-bold">
      Current user
    </div>

    <ul>
      <li>Logged In: {{ request.user.is_authenticated }}</li>
      <li>Logged in username: {{ request.user.username|default:'n/a' }}</li>
    </ul>

    <div class="pt-2 font-bold">
      Request
    </div>

    <ul>
      <li>Host: {{ request.get_host }}</li>
      <li>Path: {{ request.get_full_path }}</li>
    </ul>
  </div>
  {% endif %}

middleware.py

from time import time
from django.db import connection

class StatsMiddleware:
    """Based on https://github.com/bernd-wechner/django-stats-middleware."""

    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        if not request.user.is_superuser:
            return self.get_response(request)

        if request.path.startswith("/do-not-profile-me"):  # ignore certain paths
            return self.get_response(request)

        # Get number of db queries before we do anything
        original_query_count = len(connection.queries)

        # Time the view
        start = time()
        response = self.get_response(request)
        total_time = time() - start

        # Compute the query count for the queries just run
        query_count = len(connection.queries) - original_query_count

        stats = f"""
<div class="pt-2 font-bold">
    Stats
</div>

<ul>
    <li>Total Time: {total_time * 1000:.1f}ms</li>
    <li>Number of Queries: {query_count:,}</li>
</ul>
"""

        # Replace the stats if it's in the template
        if response:
            if content := getattr(response, "content", None):
                response.content = content.decode().replace("<!-- DEBUG STATS -->", stats)
                response["Content-Length"] = str(len(response.content))

        return response

@djpeacher improved on this idea and made a package that I'd recommend using: https://github.com/djpeacher/django-chronos.