Generate a HeaderDict based on django request object meta data.

def from_request(cls, request):
        """Generate a HeaderDict based on django request object meta data."""
        request_headers = HeaderDict()
        other_headers = ['CONTENT_TYPE', 'CONTENT_LENGTH']

        for header, value in iteritems(request.META):
            is_header = header.startswith('HTTP_') or header in other_headers
            normalized_header = cls._normalize_django_header_name(header)

            if is_header and value:
                request_headers[normalized_header] = value

        return request_headers