Django Middleware to redirect to a root domain

root_domain.py

import re

from django import http
from django.utils import six
from django.utils.http import urlquote


WWW_PATTERN = re.compile(r"www\.")


class RootDomainRedirectMiddleware(object):
    """
    Inspired by Django"s CommonMiddleware, performs the opposite of
    PREPEND_WWW by stripping www from the front of a host
    """
    response_redirect_class = http.HttpResponsePermanentRedirect

    def process_request(self, request):
        """
        Remove WWW from the hostname
        """
        host = request.get_host()

        old_url = [host, request.path]
        new_url = old_url[:]

        if (old_url[0] and re.match(WWW_PATTERN, old_url[0])):
            new_url[0] = re.sub(WWW_PATTERN, "", old_url[0])

        if new_url == old_url:
            # No redirects required.
            return

        if new_url[0]:
            newurl = "%s://%s%s" % (
                request.scheme,
                new_url[0], urlquote(new_url[1]))
        else:
            newurl = urlquote(new_url[1])

        if request.META.get("QUERY_STRING", ""):
            if six.PY3:
                newurl += "?" + request.META["QUERY_STRING"]
            else:
                # `query_string` is a bytestring. Appending it to the unicode
                # string `newurl` will fail if it isn"t ASCII-only. This isn"t
                # allowed; only broken software generates such query strings.
                # Better drop the invalid query string than crash (#15152).
                try:
                    newurl += "?" + request.META["QUERY_STRING"].decode()
                except UnicodeDecodeError:
                    pass
        return self.response_redirect_class(newurl)