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From Alex Epshteyn <alexander.epsht...@gmail.com>
Subject Re: Large HTML file not getting compressed despite compression enabled
Date Fri, 18 Apr 2008 05:46:13 GMT

Turned out it was the file size.  If I arbitrarily trim the file to be just
under 50 KB the compression will work.  

Looks like the Connector's compression facility is checking for an upper
limit on stream length or something like that.

Does anyone know of a way to disable this upper bound?

Thanks,
Alex



Alex Epshteyn wrote:
> 
> I finally had some time to try to track down this problem further.  I set
> the log levels to ALL, but still nothing useful showing up.  However, I
> found a curious thing in my access log.  Consider this snippet:
> 
> 76.19.64.19 - - [18/Apr/2008:04:29:37 +0000] "GET /theme.css HTTP/1.1" 200
> 6360
> 76.19.64.19 - - [18/Apr/2008:04:29:37 +0000] "GET
> /B2200E18EF2035F53CA3D7E241122BB6.cache.html HTTP/1.1" 200 -
> 
> The theme.css file is served up gzipped but
> B2200E18EF2035F53CA3D7E241122BB6.cache.html is not! Notice the "-" printed
> at the very end.  The doc for the access log valve describes this field as
> "Bytes sent, excluding HTTP headers, or '-' if zero".  So the access log
> thinks that zero bytes are being sent for this file.
> 
> This is not true, as the file does get properly served, just not gzipped. 
> Seems like an indication of some other problem, though.
> 
> Does anyone have any ideas?
> 
> Here is the file itself if any of the contributors reading this would like
> to try to debug.  I'd try it myself, but I can't repro the problem in my
> Windows dev environment - it only happens in my CentOS production
> environment.  (Hope the attachment worked - I'm writing this from Nabble).
> 
> 
> http://www.nabble.com/file/p16760347/B2200E18EF2035F53CA3D7E241122BB6.cache.html
> B2200E18EF2035F53CA3D7E241122BB6.cache.html 
> 
> Here are the possible causes I can think of right now: 1) the file is too
> big, almost 200 KB 2) the dual-extension, .cache.html 3) filename too
> long.  That's pretty much it.  I don't think it's the contents inside the
> file - I've gone through several incarnations of these (they are generated
> by my compiler), and not a single one has successfully gotten gzipped.
> 
> Thanks again for your time,
> Alex
> 
> 
> Alex Epshteyn wrote:
>> 
>> I have Tomcat's compression enabled:
>> 
>> <Connector port="8080" maxHttpHeaderSize="8192"
>>                maxThreads="200" minSpareThreads="25" maxSpareThreads="75"
>>                enableLookups="false" redirectPort="8443"
>> acceptCount="100"
>>                connectionTimeout="20000" disableUploadTimeout="true"
>>                compression="on"
>>                compressionMinSize="2048"
>>                noCompressionUserAgents="gozilla, traviata"
>>               
>> compressableMimeType="text/html,text/xml,text/javascript,text/css"/>
>> 
>> It works as expected for all my resources (stylesheets, scripts, etc)
>> except for one static file, which has the extension .cache.html (in
>> case you're wondering, it contains scripts generated by GWT).  This
>> file is pretty large - about 150K, but Tomcat doesn't compress it for
>> some reason.
>> 
>> Here are the response headers for this file (I have a custom filter
>> that sets the cache headers prior to forwarding the request up the
>> chain):
>> 
>> Server	Apache-Coyote/1.1
>> Cache-Control	public, max-age=315360000
>> Expires	Wed, 28 Mar 2018 18:58:38 GMT
>> Etag	W/"136900-1206809984000"
>> Last-Modified	Sat, 29 Mar 2008 16:59:44 GMT
>> Content-Type	text/html
>> Content-Length	136900
>> Date	Sun, 30 Mar 2008 20:44:14 GMT
>> 
>> Here are the response headers for a file that gets properly compressed
>> (which also passes through the same filter):
>> 
>> Server	Apache-Coyote/1.1
>> Pragma	no-cache
>> Cache-Control	max-age=0, no-store, no-cache, must-revalidate
>> Expires	Thu, 01 Jan 1970 00:00:00 GMT
>> Etag	W/"4869-1206809984000"
>> Last-Modified	Sat, 29 Mar 2008 16:59:44 GMT
>> Content-Type	text/javascript
>> Transfer-Encoding	chunked
>> Content-Encoding	gzip
>> Vary	Accept-Encoding
>> Date	Sun, 30 Mar 2008 20:44:14 GMT
>> 
>> I don't see any relevant errors in my log files.  I'm using Tomcat
>> 5.5.26 on Linux.   As a strange twist, the file does get compressed
>> properly with Tomcat 5.5.26 on Windows.
>> 
>> Any ideas?
>> 
>> Thanks in advance for your help!
>> 
>> Alex
>> 
> 
> 

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