#!/usr/local/bin/perl
#	
#	Name	:cookiead
#	Author	:Kang SoonLai
#	Date	:Wed Nov 20 1996, 03:26:04 AM	v1.0
#	Last Mod:Wed Apr 09 1997, 03:37:12 PM	v1.1
#		 Fri Oct 17 18:01:11 CDT 1997	v1.2
#			- added statistics for banners
#	Path	:/users/skang/public_html/programs/cookiead
#	Email	:skang@ittc.ukans.edu
#	WWW	:http://www.ittc.ukans.edu/~skang
#
#	This is an ad banner script that randomly displays the banner img and 
#	correctly(hopefully) routes the ref to the correct URL.
#	** DOES NOT require server side	include! **
#
#	Usage:
#	1. Change the $dir var to where u want the stat to be store at. 
#	2. Create a rc file named stat.  This file stores the urls, the 
#	paths to the banner, freq of appearence.  eg:
#	
#	url1%%img_file1%%freq_of_appearence
#	url2%%img_file2%%freq_of_appearence
# 	.
#	.
#
#	If you plan to use cookiead for several other pages, you can then create
#	another rc files, and you must append the name of the rc file to the 
#	cgi call.   Here are the examples: 
#  
#	default:
#	<A HREF="cgi-bin/cookiead/url"><IMG 
#		SRC="cgi-bin/cookiead/img" ALT="Sponsor"></A>
#
#	rc file, stat2, given:
#	<A HREF="cgi-bin/cookiead/url/stat2"><IMG 
#		SRC="cgi-bin/cookiead/img/stat2" ALT="Sponsor"></A>
#
#	3.	create a pics dir in the $dir where you have just created. 
#		put all the image files there.  eg: $dir/pics
#
#	4.	crete a tmp dir in $dir as well, and make the permission to 757
#		by using this command:	chmod 757 tmp
#	
#	4.	you might want to get the rmads script as well.  this script
#		cleans up the tmp dir.  read the script for info on setting up
#		a cron job.
#	
#	5.	if you want a statistic file, then create another file with 
#		the exact rc file name but with the extension .db, and change 
#		the permission to 646.  it must be empty file.
#			touch stat.db; chmod 646 stat.db
#
#	With the capability to set cookie on cookieable browsers, it is more
#	reliable to direct to appropriate url.
#	
#	Due to some servers do not support cookie header, a "Location" http
#	header cannot be used.  As a result, I had to open the image file
#	and print the data to STDOUT.  If your server supports cookie header,
#	then you are welcome to comment out the output img part, and add 
#	the Location tag:
#		print "Location: http://$URL\n\n";
#	Remember to delete one "\n" from the "content" header!
#
###############################################################################

# the base url to the banner images, this is the url where all the banner pics
# located.  uncomment this out if your server can support cookie.  also,
# you need to go to the bottom 10 lines to uncomment the print statements.
#  For some
# reason, my server doesn't allow setting cookie and the Location to be set
# together.  
#
#$IMGURL = "www.ittc.ukans.edu/~skang/banner/pics";

# dir to where the banner info located.  contains the stat file, pics dir,
# tmp/ip files, etc.
#
$dir = "/home/skang/public_html/banner";

$default = "www.granax.com/~skang/freenshare.html";

# if your server has more than one domain names, then you can specify all of 
# them here.  this is optional.  it is used to set cookie.
$domain = '';

# cookie, this contains the URL of the page, this is the thing that Netscape
# supports.
#
#($name,$cookie) = split(/=/,$ENV{'HTTP_COOKIE'});
$cookie = $ENV{'HTTP_COOKIE'};
#$cookie =~ s/([^URL]*)URL=([^;]*);.*/$2/;
$cookie =~ /URL=([^;]*)/;
$cookie = $1;

# get the remote IP so that in case the ip file is not created, we can still
# kind of guess the link to go to.
#
#$ip = $ENV{'REMOTE_ADDR'} ? "tmp/$ENV{'REMOTE_ADDR'}" : "tmp/129.237.125.68";
$ip = "tmp/$ENV{'REMOTE_ADDR'}";

# get the action from the env var.  two actions are allowed, 
# 'url' - points to the "sponsor" page.
# 'img' - returns the img to be displayed.
#
($dum,$action,$file) =  split(/\//,$ENV{'PATH_INFO'});
#$action =~ s/\///;
#$action = "url";

# this file contains the information about the banner to be displayed
# it has the format ->	url%%img%%frequency%%showed_frequency
# ** currently, the showed_freq is not implemented yet.
#
$file = "stat" unless $file;


######################
# 	ACTION!
######################
# redirect url #### 
#
if  ($action eq 'url') {

	if ( -e "$dir/$file.db" && open(F,"+<$dir/$file.db") ) {
		my($raw,$hits,$url);
		my(@raws,@hits,@urls);
		my $gotit = 0;
		while (<F>) {
			chop;
			($raw,$hits,$url) = split(/\t/,$_);
			if ($url eq $cookie) { $hits++; $gotit=1; }	
			push @urls,$url;
			push @raws,$raw;
			push @hits,$hits;
		}
		seek(F,0,0);
		for $raw (@raws) {
			$hits = shift @hits;
			$url = shift @urls;
			print F "$raw	$hits	$url\n";
		}
		print F "1	1	$cookie\n" unless $gotit;
	}

	# there is cookie.
	if ( $cookie ) {
		#print "Content-type: text/html\n\n";
		print "Location: http://$cookie\n\n";
		#print "<P>$ENV{HTTP_COOKIE}";
	
	}

	# redirect URL ####  non cookie ####
	####################################
	# browser does not support cookie, we need to open the tmp file 
	# created to redirect to new URL.
	elsif ( (-e "$dir/$ip") && $action eq 'url' ) {

		open(TMP,"$dir/$ip"); 
		$URL = <TMP>;
		close(TMP);
		unlink("$dir/$ip");
		print "Location: http://$URL\n\n";
	} else {
		print "Location: http://$default\n\n";
	}		


#
# generate a random img and url to go to, and set cookie no matter the browser 
# supports cookie or not.  if there is no HTTP_COOKIE defined, then create a 
# file so that the action 'url' will be able to get the url.
} elsif ($action eq 'img') {


	open(F,"$dir/$file") || die "Error opening file $dir/$file: $!\n";

	while (chop($line = <F>)) {
		($url,$img,$freq,$sfreq) = split(/%%/,$line);
		push(@imgs,"$img");
		push(@urls,"$url");
		#push(@freqs,$freq);
		#push(@sfreqs,$sfreq);
	
		for ($i=0; $i<$freq; $i++) {
			push(@imgs,"$img");
			push(@urls,"$url");
		}
	}
	close(F);

	# pick a random seed to randomly display banner
	srand(time|$$);
	$random = int(rand(scalar(@imgs)));

	$cookie = $urls[$random];
	$pic = "$imgs[$random]";

	# record hits
	if ( -e "$dir/$file.db" && open(F,"+<$dir/$file.db") ) {
		my($raw,$hits,$url);
		my(@raws,@hits,@urls);
		my $gotit = 0;
		while (<F>) {
			chop ;
			($raw,$hits,$url) = split(/\t/,$_);
			if ($url eq $cookie) { $raw++; $gotit=1; }	
			push @urls,$url;
			push @raws,$raw;
			push @hits,$hits;
		}
		seek(F,0,0);
		for $raw (@raws) {
			$hits = shift @hits;
			$url = shift @urls;
			print F "$raw	$hits	$url\n";
		}
		print F "1	0	$cookie\n" unless $gotit;
	}

	# if there is no cookie, then we can write the URL, if there 
	# is cookie 
	# then we don't write to file since it is not necessary.
	# write the URL so that when user clicks on the link, will 
	# bring to the exact page!
	if (! $ENV{'HTTP_COOKIE'} && ! $ENV{HTTP_USER_AGENT} =~ /Mozilla/ ) {
		open(TMP,">$dir/$ip") || 
			die "Error opening file $dir/$ip: $!\n";
		print TMP $cookie;
		print TMP "\n$ENV{HTTP_USER_AGENT}";
		close(TMP);
	}

	# set cookie 
	if (defined $domain) {
		print "Set-Cookie: URL=$cookie; path=/; $domain\n";
	} else {
		print "Set-Cookie: URL=$cookie; path=/\n";
	}
	#print "Pragma: no-cache\n";
	print "Content-type: image/gif\n\n";

	# output image
	open(IMG,"$dir/pics/$pic");
	#while ( $img=<IMG>) {	print $img; }
	print <IMG>;
	close(IMG);

	# if your server supports cookies, then uncomment the two print 
	# statements. and comment the above three lines.
	# also, you need to comment this too 
	# print "Content-type: image/gif\n\n";
	#
	# make sure that the browser displays the new image,
	# Netscape version 2.*(1.*) do not do that.
	#print "Pragma: no-cache\n";
	#print "Location: http://$IMGURL/$pic\n\n";

} else {
	print "Content-type: text/html\n\n";
	print "Unknown action.  Please check your url\n";
	exit;
}