ID: 40325
Updated by: [EMAIL PROTECTED]
Reported By: nicolas dot grekas+php at gmail dot com
-Status: Assigned
+Status: Wont fix
-Bug Type: HTTP related
+Bug Type: Zlib Related
Operating System: All
PHP Version: 5.2.0
Assigned To: mike
New Comment:
We can't fix this issue, due to the nature of PHP output handlers.
Consider he following code snippet:
<?php
ob_start("ob_gzhandler");
ob_end_clean();
?>
We'll get a plain response plus the Vary header, not really better
either.
I'd suggest you to use mod_deflate or f.e. always send the Vary header
yourself when using a zlib output handler:
<?php
header("Vary: Accept-Encoding");
ob_start("ob_gzhandler");
?>
Previous Comments:
------------------------------------------------------------------------
[2007-03-21 14:42:15] nicolas dot grekas+php at gmail dot com
I'm sorry to insist, but this is for the good of PHP :) This bug is not
bogus.
Here is the related RFC2616 HTTP1.1-14.44 excerpt that is not honored
by ob_gzhandler : "An HTTP/1.1 server SHOULD include a Vary header field
with any cacheable response that is subject to server-driven
negotiation.".
In fact today, ob_gzhandler do send a "Vary: Accept-Encoding" header
when the client accepts gzip or deflate. (This is the case for example
for IE, Gecko, and many browsers.)
BUT : the RFC says that the vary header should be send IF
_a_negociation_occurs_. That means that the Vary header is not meant to
be send based on the result of any negociation. The point is : if you
negociate, then you should send a Vary header, whatever the result of
the nego.
What ob_gzhandler actually does is :
negociate, then if gzip/deflate accepted, send a Vary
What it should do is :
send a Vary, then negociate.
This but is in no way related to the bug of IE regarding vary headers :
the current conditions requested by ob_gzhandler to send its vary header
are always met by IE (accept gzip ? => yes).
Hope it helps
------------------------------------------------------------------------
[2007-02-02 18:44:25] nicolas dot grekas+php at gmail dot com
I knew this pb for IE, and the link of php_lists is worth reading. BUT
it is NOT related to the bug I was submitting.
IE's bug with Vary header is :
IF (non-compressed-content + Vary-header)
THEN IE-dont-cache-entity
Here is my bug :
IF a resource is negotiated for compression
THEN we MUST send a Vary header.
In fact, for IE, the negotiation made by ob_gzhandler DOES ALREADY send
a Vary header. Because negotiation ends to : browser (IE) accepts
gzipped content.
So fixing this issue WONT CHANGE ANYTHING FOR IE, but will fix
corrupted caches.
Should I explain more deeply the issue ?
Regards,
Nicolas
------------------------------------------------------------------------
[2007-02-02 17:02:44] [EMAIL PROTECTED]
Thanks, awesome read.
------------------------------------------------------------------------
[2007-02-02 15:38:48] php_lists at realplain dot com
Just thought I'd add this comment that IE doesn't handle these Vary:
headers correctly (breaks caching that would usually be used). :-( See
http://lists.over.net/pipermail/mod_gzip/2002-December/006826.html
It's been awhile since I read the details, but maybe you'd want to use
"Cache-Control: private" instead or in addition to Vary:?
------------------------------------------------------------------------
[2007-02-02 13:11:50] nicolas dot grekas+php at gmail dot com
Oops : I've switched Expected and Actual results, sorry
------------------------------------------------------------------------
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/40325
--
Edit this bug report at http://bugs.php.net/?id=40325&edit=1
