From: Martin Langhoff <martin.langhoff@gmail.com>
Date: Mon, 11 Dec 2006 10:18:54 GMT
Subject: Re: kernel.org mirroring (Re: [GIT PULL] MMC update)
Message-ID: <46a038f90612110218u48b7737due56437da57091547@mail.gmail.com>
In-Reply-To: <200612110959.56492.jnareb@gmail.com>

On 12/11/06, Jakub Narebski <jnareb@gmail.com> wrote:
> I was thinking not about ending execution, but about not sending script
> output but sending HTTP 304 Not Modified reply by Apache.
>
> I meant the following sequence of events:
>  1. Script sends headers, among those Last-Modified and/or ETag
>  2. Apache scans headers (e.g. to add its own), notices that Last-Modified
>     is earlier or equal to If-Modified-Since: sent by browser or reverse
>     proxy, or ETag matches If-None-Match:, and sends 304 instead of script
>     output
>  3. Script finishes execution, it's output sent to /dev/null
>
> Again, I don't know if Apache (or any other web server) does that.

It doesn't. You want to take the decision to send a 304, cleanup and
exit _inside_ the CGI. If it was up to apache, then the CGI script
would end up creating the (potentially expensive to produce) content
just to see it sent to /dev/null OR if apache was to terminate
execution of the CGI more violently, the CGI wouldn't have a chance to
cleanup and release resources.

So it's a matter of setting the header to 304 and exiting.

cheers,


martin