# mod_ext_filter directive to define a filter
# to HTML-ize text/c files using the external
# program /usr/bin/enscript, with the type of
# the result set to text/html
ExtFilterDefine c-to-html mode=output \
intype=text/c outtype=text/html \
cmd="/usr/bin/enscript --color -W html -Ec -o - -"

<Directory "/export/home/trawick/apacheinst/htdocs/c">
# core directive to cause the new filter to
# be run on output
SetOutputFilter c-to-html

# mod_mime directive to set the type of .c
# files to text/c
AddType text/c .c

# mod_ext_filter directive to set the debug
# level just high enough to see a log message
# per request showing the configuration in force
ExtFilterOptions DebugLevel=1
</Directory>

# mod_ext_filter directive to define the external filter
ExtFilterDefine gzip mode=output cmd=/bin/gzip

<Location /gzipped>
# core directive to cause the gzip filter to be
# run on output
SetOutputFilter gzip

# mod_header directive to add
# "Content-Encoding: gzip" header field
Header set Content-Encoding gzip
</Location>

# mod_ext_filter directive to define a filter
# which runs everything through cat; cat doesn't
# modify anything; it just introduces extra pathlength
# and consumes more resources
ExtFilterDefine slowdown mode=output cmd=/bin/cat \
preservescontentlength

<Location />
# core directive to cause the slowdown filter to
# be run several times on output
#
SetOutputFilter slowdown;slowdown;slowdown
</Location>

# mod_ext_filter directive to define a filter which
# replaces text in the response
#
ExtFilterDefine fixtext mode=output intype=text/html \
cmd="/bin/sed s/verdana/arial/g"

<Location />
# core directive to cause the fixtext filter to
# be run on output
SetOutputFilter fixtext
</Location>

# Trace the data read and written by mod_deflate
# for a particular client (IP 192.168.1.31)
# experiencing compression problems.
# This filter will trace what goes into mod_deflate.
ExtFilterDefine tracebefore \
cmd="/bin/tracefilter.pl /tmp/tracebefore" \
EnableEnv=trace_this_client

# This filter will trace what goes after mod_deflate.
# Note that without the ftype parameter, the default
# filter type of AP_FTYPE_RESOURCE would cause the
# filter to be placed *before* mod_deflate in the filter
# chain. Giving it a numeric value slightly higher than
# AP_FTYPE_CONTENT_SET will ensure that it is placed
# after mod_deflate.
ExtFilterDefine traceafter \
cmd="/bin/tracefilter.pl /tmp/traceafter" \
EnableEnv=trace_this_client ftype=21

<Directory /usr/local/docs>
SetEnvIf Remote_Addr 192.168.1.31 trace_this_client
SetOutputFilter tracebefore;deflate;traceafter
</Directory>

データをトレースするフィルタ:

#!/usr/local/bin/perl -w
use strict;

open(SAVE, ">$ARGV[0]")
or die "can't open $ARGV[0]: $?";

while (<STDIN>) {
print SAVE $_;
print $_;
}

close(SAVE);

例

ExtFilterOptions LogStderr DebugLevel=0