Configure Apache with with mod_deflate

mod_deflate is included in the Apache 2.0.x source package, and compiling it in is a simple matter of adding it to the configure command.

./configure --enable-modules=all --enable-mods-shared=all --enable-deflate

When the server is made and installed, the GZIP-encoding of documents can be enabled in one of two ways: explicit exclusion of files by extension; or by explicit inclusion of files by MIME type. These methods are specified in the httpd.conf file.

Explicit Exclusion

SetOutputFilter DEFLATE
DeflateFilterNote ratio
SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.(?:exe|t?gz|zip|bz2|sit|rar)$ no-gzip dont-vary
SetEnvIfNoCase Request_URI \.pdf$ no-gzip dont-vary

Explicit Inclusion

DeflateFilterNote ratio
AddOutputFilterByType DEFLATE text/*
AddOutputFilterByType DEFLATE application/ms*
application/vnd* application/postscript

Both methods enable the automatic GZIP-encoding of all MIME-types, except image and PDF files. Image files and PDF files are excluded as they are already in a highly compressed format. In fact, PDFs become unreadable by Adobe's Acrobat Reader if they are further compressed by mod_deflate or mod_gzip.