On Wed, 16 Dec 2009 14:54:57 -0600 Neil Schemenauer  wrote:

> Greetings Quixote and QP users,
>
> [tl;dr: see the patch below]
>
> Recently I ran into trouble with certain client and the problem
> appears to be caused by unexpected caching of dynamic resources. I
> haven't been able to conclusively determine the problem yet, but
> while looking into it, I realized that Quixote's use of the Expires
> header is not sufficient to prevent unwanted caching (QP inherited
> the same code). Has anyone else seen caching problems "in the wild"
> where "Expires: -1" is not sufficient?
>

Yes. In one case I had to set cache-control to must-revalidate in every
response because of a caching proxy between the client and the server.

....
> +        the number of seconds the response may be cached.  The default
> +        is 0, meaning don't cache at all.  This variable is used to set
> +        the HTTP expires and cache-control headers.  If set to None then
> +        no headers will not be added.

  +        no headers will be added.

....
> -                expire_date = "-1" # allowed by HTTP spec and may work better
> -                                   # with some clients
> -            headers.append(("Expires", expire_date))
> +                # The is the default case and makes sense for a dynamically

  +                # This is the default case and makes sense for a dynamically

--
Patrik