ungleich-no-ipv4-here/no_ipv4_here/views.py

from django.shortcuts import render
from django.http import HttpResponse


def index(request):
    back_to_url = ""
    if "back_to" in request.GET:
        back_to_url = request.GET["back_to"]
    elif 'HTTP_HOST' in request.META:
        back_to_url = request.META['HTTP_HOST']
    context = {
        'domain': back_to_url
    }

    if back_to_url != "":
        return render(request, 'index.html', context)
    else:
        return HttpResponse(
            """Sorry, this part ofAAAAAAAAAAAAAAAAAa domain is not reachable by IPv4.
            Please upgrade to IPv6 and try to reach the domain again."""
        )