[Tickets #11180] Re: gzip attachments get double gzip on download

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Ticket URL: http://bugs.horde.org/ticket/11180
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  Ticket             | 11180
  Updated By         | patrickdk at patrickdk.com
  Summary            | gzip attachments get double gzip on download
  Queue              | IMP
  Version            | Git master
  Type               | Bug
  State              | Not A Bug
  Priority           | 2. Medium
  Milestone          |
  Patch              |
  Owners             |
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patrickdk at patrickdk.com (2012-05-10 00:43) wrote:

The data is not compressed a 3rd time, and I'm using lighttpd without  
the compression module (the compression module doesn't support  
compression of dynamic content, only static files anyways)

a tcpdump of the stream shows double compression:

HTTP/1.1 200 OK
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Content-Type: application/x-gzip
Content-Disposition: attachment; filename="test1.tar.gz"
Content-Encoding: gzip
Vary: Accept-Encoding
Transfer-Encoding: chunked
Date: Wed, 09 May 2012 22:01:17 GMT
Server: lighttpd/1.4.30

fff8
....................X.O..test1.tar...y<.}.?.OI.$d..(E.b.:mHN..b*.c".

compared to the real file:

_KHHOX)O at Ctest1.tar@l}y<T}{?LOIR$dO)(ERbI:mH

If I disable compress in horde config, all is fine, and everything  
works, but all pages are uncompressed, html/js/css/...

The same issue on my apache config, if I disable horde compression,  
and only use the deflate module, I get compression, plus downloads of  
the gzip attachment work properly.

Seems to be this firefox bug, I suppose:
https://bugzilla.mozilla.org/show_bug.cgi?id=610679

As long as content-encoding isn't in use, on gzip'd files, it's not an  
issue, and since mod_deflate isn't compressing already gzip content,  
it works.

Also while looking at a workaround for this, I found that the  
imp/view.php appInit nocompress option isn't used, cause the  
services/download/index.php overrides it.

I added:
'nocompress' => ((Horde_Util::getFormData('actionID') ==  
'download_all') || Horde_Util::getFormData('zip')  
||(substr_compare(Horde_Util::getFormData('fn'), 'gz', -2, 2,true)  
==0)),
do services/download/index.php appInit as a simple workaround.

The other workaround would be to completely disable hordes buildin  
compression, and use browser based compression instead, but lighttpd  
currently doesn't support that for php.