Django: ETAG middleware based on project version

gistfile1

from django.conf import settings


PROJECT_VERSION = getattr(settings, 'PROJECT_VERSION')


class ETAGMiddleware(object):

    def process_response(self, request, response):
        """
        Calculate the ETag, based on site version.
        This is amost the same as in django's own commonmiddleware,
        but we dont want the extra processing when it comes to the
        content hashing. So we just use the version number for the
        etag.
        """
        if response.has_header('ETag'):
            etag = response['ETag']
        elif response.streaming:
            etag = None
        else:
            etag = PROJECT_VERSION
        if etag is not None:
            if (200 <= response.status_code < 300
                and request.META.get('HTTP_IF_NONE_MATCH') == etag):
                cookies = response.cookies
                response = http.HttpResponseNotModified()
                response.cookies = cookies
            else:
                response['ETag'] = etag

        return response