Maniphest T19537

Turn off zlib.output_compression for 304
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Authored By

	• bzimport
	Feb 17 2009, 9:28 PM

Description

Author: ezyang

Description:
Fixes bug

When PHP has zlib.output_compression enabled, it compresses all pages output, regardless of their HTTP status code. Even empty pages get a ~13 byte empty gzipped file tacked as their response. Unfortunately, for HTTP status code 304, this is in direct violation of the specification; furthermore, if SSL and Keep-Alive are enabled, Firefox gets sufficiently confused such as to post a download page for the page immediately after the 304 with extra information afterwards (it mixes up the packets).

I've attached a patch that fixes this bug by manually turning off zlib.output_compression when a 304 is being sent. I am also coordinating with PHP's maintainers to get this fixed upstream.

Relevant links:
https://bugzilla.mozilla.org/show_bug.cgi?id=363109 (bug for Firefox getting confused by data after 304)
http://bugs.php.net/bug.php?id=42362 (bug for PHP not turning of zlib.output_compression when there is empty output)

Version: 1.15.x
Severity: normal

attachment zlib.patch ignored as obsolete

Details

Reference: bz17537

Event Timeline

• bzimport raised the priority of this task from to Medium.Nov 21 2014, 10:30 PM

• bzimport added a project: MediaWiki-General.

• bzimport set Reference to bz17537.

• bzimport added a subscriber: Unknown Object (MLST).

• bzimport created this task.Feb 17 2009, 9:28 PM

I think I've seen problems when the Content-encoding on the 304 doesn't match the cached data before; can you double-check that behavior is still consistent in this behavior mode?

ezyang wrote:

No problems on Firefox, using this test script:

<?php

if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {

ini_set('zlib.output_compression', 0);
header('HTTP/1.1 304 Not Modified');
header('Last-Modified: Tue, 17 Feb 2009 22:18:25 GMT');

} else {

header('Cache-Control=private, s-maxage=0, max-age=0, must-revalidate');
header('Last-Modified: Tue, 17 Feb 2009 22:18:25 GMT');
var_dump($_SERVER);
?><a href="">asdf</a><?php

}

ezyang wrote:

By request of Brion on IRC, it works fine on IE/Mac. :-)

ezyang wrote:

Fixes bug

Fix minor typo in patch

Attached:

zlib.patch1 KBDownload

ezyang wrote:

Some further research has found it is possible to tickle this bug in Firefox without SSL, but much more difficult.

Applied in r48540

Turn off zlib.output_compression for 304Closed, ResolvedPublicActions

Description

Details

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Turn off zlib.output_compression for 304
Closed, ResolvedPublic
Actions