#!/usr/local/bin/perl
#
# Checks the client's IP address, and returns either a random image
# or a specific image for the current month.  This allows a randomly
# changing image on the U of S home page for most people, and a
# less frequently changing image for people using the (slower)
# campus dialups.
#
# Monthly images are, eg. January.gif, February.gif, ... December.gif
#
# Written by Earl Fogel, May 1997

# Configuration
$DocumentRoot = "/www";
$ServerURL = "http://$ENV{'HTTP_HOST'}";
$Directory = "/images/mainpage";  # this is the default
@slowhosts = ("192.139.76.", "198.169.16.");

# Directory may be passed in as extra path info if you are very trusting
# $Directory = $ENV{'PATH_INFO'} if $ENV{'PATH_INFO'} =~ /./;

foreach $ip (@slowhosts) {
    $ip =~ s/\./\\\./;
    $slow = 1 if $ENV{'REMOTE_ADDR'} =~ /^$ip/;
}

if ($slow) {
    @months = ( "January", "February", "March", "April", "May", "June",
	"July", "August", "September", "October", "November", "December");

    ($sec,$min,$hour,$mday,$mon,$year) = localtime(time);

    $newURL = "$ServerURL$Directory/$months[$mon].gif";

} else {
    chdir "$DocumentRoot/$Directory"
	|| chdir "$Directory"
	    || die("Can't cd to $Directory: $!\n");

    srand;				# seed the random number generator
    @pool = <*.gif>;			# list of gif files in $Directory
    $pick = int rand $#pool+1;		# pick a random number
    $file = $pool[$pick];		# file corresponding to that number

    $newURL = "$Directory/$file";
    $newURL =~ s#//#/#g;
    $newURL =~ "$ServerURL$Directory/$file";
}

print "Status: 302\n";
print "Location: $newURL\n\n";