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#847 Clarify about filtering compressed content
Privoxy 3.0.17
Under http://config.privoxy.org/user-manual/actions-file.html#FILTER there is a "Notes" section which says, in part:
Inappropriate MIME types, such as zipped files, are not filtered at all. ...
Compressed content can't be filtered either, unless Privoxy is compiled with zlib support (requires at least Privoxy 3.0.7), in which case Privoxy will decompress the content before filtering it.
At first glance, this seems self-contradictory (compressed content is never filtered, but sometimes it is filtered). Can it be clarified in the HTML file for the sake of readers who are not quite technically adept enough to understand this apparent contradiction themselves? Thanks in advance.
Thanks for the suggestion.
Should be fixed in the SGML file now:
http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/doc/source/user-manual.sgml?r1=2.135&r2=2.136
The HTML file will get the fix the next time it's regenerated.
Thanks for updating the text. I originally submitted this issue because the ability of web servers to provide text files in compressed form may not be known to some Privoxy users.
The following is my attempt at a patch (to be copied, pasted, & edited manually) to resolve this issue. The suggested patch would replace the paragraph of the Privoxy 3.0.17 user manual starting with "Compressed content can't be filtered either."
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A different matter is HTTP compression, in which files are sent compressed by the web server according to the Accept-Encoding client header and the Content-Encoding server header. Files of any MIME type can be sent with HTTP compression (although usually only text files are sent HTTP-compressed, because most picture formats are inherently compressed). HTTP-compressed content will be decompressed and filtered by &my-app; if:
1. &my-app; is compiled with zlib support, and
2. the appropriate compression library exists on the computer that &my-app; is running on, and is loadable by &my-app;, and
3. a supported compression algorithm is used (gzip or deflate).
To find out whether an installed copy of &my-app; was compiled with zlib support: First, browse to http://config.privoxy.org/show-status (which can also be reached by browsing to http://p.p/, then clicking "View & change the current configuration"). Then, look in the "Conditional #defines" section for FEATURE_ZLIB to be marked as Yes.
I believe Privoxy users who care about the details of HTTP compression will have no trouble looking it up elsewhere.