class RedirectMiddleware(object):
    def process_request(self, request):
        if request.is_ajax():
            return None
        try:
            site = Site.objects.get_current()
        except:
            return None
        host = request.get_host()
        if host != site.domain:
            if host.endswith('.' + site.domain):
                subdomain = host.replace('.' + site.domain, '')
                if subdomain not in settings.DENIED_SUBDOMAINS:
                    try:
                        callback, callback_args, callback_kwargs = resolve(request.path, settings.SUBDOMAINS_ROOT_URLCONF)
                    except:
                        return HttpResponseRedirect('http://' + site.domain + request.path)
                    else:
                        callback_kwargs.update({'user': subdomain})
                        return callback(request, *callback_args, **callback_kwargs)
            return HttpResponseRedirect('http://' + site.domain + request.path)