#!/bin/sh
#
# John's No-ADS proxy script
#      http://www.schooner.com/~loverso/no-ads/
#      loverso@schooner.com
#
# Copyright 1996-2003, John LoVerso.  All Rights Reserved.
#
#      Permission is given to distribute this file, as long as this
#      copyright message and author notice are not removed, and no
#      monies are exchanged.
#
#      No responsibility is taken for any errors on inaccuracies inherent
#      either to the comments or the code of this program, but if reported
#      to me, then an attempt will be made to fix them.
#
# $Id: noproxy,v 1.11 2008/10/23 18:41:16 loverso Exp loverso $

#
# This fakes an HTTP transaction by it just returning a canned response.
#
# Normally, this is run from inetd with this line in inetd.conf
# (remember to "kill -HUP" the inetd process after changing that file)
#
#	# no-ads proxy
#	3421 stream tcp nowait nobody /usr/local/lib/www/noproxy noproxy
#
# 3421 is either an arbitrary TCP port number or TCP service name;
# just make sure you use the same value in "no-ads.pac".
#
###############################################################################

# Pick one of the noproxy schemes and use it at the end

###############################################################################
#
# Just deny the connection
#
deny() {
	echo HTTP/1.0 501 No Ads Accepted
	echo ""
}

###############################################################################
#
# Return redirection to "no-ads" image,
# so you can tell when an ad is suppressed.
#
redir() {
	printf '%s\r\n%s\r\n%s\r\n%s\r\n%s\r\n' \
		"HTTP/1.0 301 No Ads Accepted" \
		"Date: Mon, 20 Oct 1997 12:25:47 GMT" \
		"Server: /bin/sh" \
		"${1-"Location: http://freebase/~loverso/no-ads.gif"}" \
		""
}

###############################################################################
#
# Return an image.  Returns either noproxy.clear.gif or noproxy.noads.gif.
#
# Netscape 4.0 bug with <script SRC="http://adforce.imgis.com/...">
# causes crash when returning an image.  This may have been fixed since.
#
# Netscape bug with <layer> causes such references to use the embedded
# link as a title.  alta vista uses <layer> for ads.  damn.
#
image() {
	result="404 No Ads Accepted"
	result="200 No Ads Accepted"
	image=noads.gif size=202
	image=blocked.gif size=129
	image=clear.gif size=43
	printf '%s\r\n' \
		"HTTP/1.0 $result" \
		"Date: Mon, 12 Nov 2001 12:25:47 GMT" \
		"Server: none" \
		"Last-Modified: Mon, 20 Oct 1997 12:25:47 GMT" \
		"Expires: Mon, 20 Oct 2020 20:20:20 GMT" \
		"Content-Length: $size" \
		"Content-Type: image/gif" \
		"" |
	cat - $0.$image
}

###############################################################################
#
empty() {
	result="404 No Ads Accepted"
	result="200 No Ads Accepted"
	r=${1-' '}
	size=${1:+${#r}}
	size=${size:-"1"}
	printf '%s\r\n' \
		"HTTP/1.0 $result" \
		"Date: Mon, 12 Nov 2001 12:25:47 GMT" \
		"Server: none" \
		"Last-Modified: Mon, 20 Oct 1997 12:25:47 GMT" \
		"Expires: Mon, 20 Oct 2020 20:20:20 GMT" \
		"Content-Length: $size" \
		"Content-Type: text/plain" \
		"" "$r"
}

###############################################################################
#
fourohfour() {
	result="404 No Ads Accepted"
	printf '%s\r\n' \
		"HTTP/1.0 $result" \
		"Date: Mon, 12 Nov 2001 12:25:47 GMT" \
		"Server: none" \
		"" 
}


###############################################################################
#
# If we got this, no-ads sent it to the blackhole
control() {
	result="200 OK"
	printf '%s\r\n' \
		"HTTP/1.0 $result" \
		"Server: none" \
		"Content-Type: text/html" \
		"" \
		"<h1>Successful: <i>$url</i></h1>" \
		"<blockquote>" \
		"From `basename $0`<br>" \
		"running from `dirname $0`<br>" \
		"running on `hostname`<br>" \
		"as user `id -un`<br>" \
		"at `date`<br>" \
		"</blockquote>" \
		""
}

###############################################################################
#
#
page() {
	file=$1
	result="200 OK"
	printf '%s\r\n' \
		"HTTP/1.0 $result" \
		"Content-Type: text/html" \
		""
	cat $file
}

f22() {
    page=`basename $url`
    page "f22l3/$page"
}

###############################################################################

# quaff HTTP request + 1st line of headers
read meth url http
read h f

# Gack!  This is needed on Linux, as Linux TCP does not handle half
# open TCP connections (WHY!?) and will reset a connection with unread data
cat <&0 > /dev/null &
catpid=$!
# close stdin
exec <&-

# debug log
echo "`date`: $url" >> /var/tmp/.noproxy.log

cd `dirname $0`

#####
#
# Choose one of deny, redir, image, or fourohfour
# or... use the case statement to selective return a response
#
###deny
###redir
###image
###fourohfour

case "$url" in
http://no-ads.int/*|*no-ads.test*)	control ;;

# hack to make F22 work
http://*novaworld.net/*)		f22 ;;

*htm|*html|*.png|*.jpg|*.gif)		image ;;
*js)					empty '//';;
*)					empty ;;
esac


# close (for broken Linux)
exec >&- 2>&-
kill $catpid

exit 0