Re: Why isn't Cache-Control removed with remove_content_headers?

On Wed, Jan 25, 2006 at 01:49:16AM -0800, Gisle Aas wrote:
> Bill Moseley <moseley@xxxxxxxx> writes:
> 
> > I've been setting both Cache-Control max-age and Expires.  But I
> > noticed that remove_content_headers() only removes the
> > @entity_headers which only includes Expires.
> > 
> > Should remove_content_headers remove both?
> 
> I'm not sure.  RFC 2616 section 4.5 starts out saying "There are a few
> header fields which have general applicability for both request and
> response messages, but which do not apply to the entity being
> transferred." and Cache-Control is one of these.  This implies that
> remove_content_headers shouldn't touch it.

I'm not sure either.  Expires and Cache-Control have somewhat similar
function (section 14.9.3 discusses what happens when both are
present) so I thought it odd that one would be removed and not the
other.

Like Expires, Cache-Control does describe what to do with the content
in a response, so would seem reasonable to consider it a content
header.  On there other hand, I believe it's possible to include
Expires and Cache-Control on a 304 response that contains no content.

I'm not sure why Cache-Control isn't listed in 7.1 Entity Header
Fields, as Cache-Control can override Expires as noted in 14.21.

So, ya, I'm not sure.

> Does the current behaviour create a problem in your application?

Not really a problem.  I have a response that includes Last-Modified,
Content-Length, Cache-Control max-age, and Expires. In some cases that
content is further processed and becomes non-cacheable.  So I need to
remove all headers except Last-Modified (and even leaving
last-modified is questionable).

So I was trying to use remove_content_headers for a different
purpose, I suppose.


-- 
Bill Moseley
moseley@xxxxxxxx