# documentação Django 2.0.8

# Código fonte para django.contrib.sites.middleware

    from django.utils.deprecation import MiddlewareMixin

    from .shortcuts import get_current_site

    class CurrentSiteMiddleware(MiddlewareMixin):
        """
        Middleware that sets `site` attribute to request object.
        """

        def process_request(self, request):
            request.site = get_current_site(request)