python类Feed()的实例源码

def __call__(self, request, *args, **kwargs):
        """
        Copied from django.contrib.syndication.views.Feed

        Supports file_name as a dynamic attr.
        """
        try:
            obj = self.get_object(request, *args, **kwargs)
        except ObjectDoesNotExist:
            raise Http404('Feed object does not exist.')
        feedgen = self.get_feed(obj, request)
        response = HttpResponse(content_type=feedgen.mime_type)
        if hasattr(self, 'item_pubdate') or hasattr(self, 'item_updateddate'):
            # if item_pubdate or item_updateddate is defined for the feed, set
            # header so as ConditionalGetMiddleware is able to send 304 NOT MODIFIED
            response['Last-Modified'] = http_date(
                timegm(feedgen.latest_post_date().utctimetuple()))
        feedgen.write(response, 'utf-8')

        filename = self._get_dynamic_attr('file_name', obj)
        if filename:
            response['Content-Disposition'] = 'attachment; filename="%s"' % filename

        return response

def _get_dynamic_attr(self, attname, obj, default=None):
        """
        Copied from django.contrib.syndication.views.Feed (v1.7.1)
        """
        try:
            attr = getattr(self, attname)
        except AttributeError:
            return default
        if callable(attr):
            # Check co_argcount rather than try/excepting the function and
            # catching the TypeError, because something inside the function
            # may raise the TypeError. This technique is more accurate.
            try:
                code = six.get_function_code(attr)
            except AttributeError:
                code = six.get_function_code(attr.__call__)
            if code.co_argcount == 2:       # one argument is 'self'
                return attr(obj)
            else:
                return attr()
        return attr

    # NOTE: Not used by icalendar but required
    #       by the Django syndication framework.