#!/usr/bin/perl
# The third-simplest redirector on the planet, written 9/22/5 by Aaron.
# It used to be the case that subdomains of columbia villages were reached via URLs like
# http://www.columbiavillages.org/subdomain_name; now they're proper subdomains, like
# http://subdomain_name.columbiavillages.org/. Since they've been the old way for so long,
# and since it's such a bloody pain in the neck to find every instance of the old style and
# replace it when there are things like variable interpolation to consider, and so that the
# old links which have been published won't go bad, I've created this simple redirection tool.

# It's not so simple to set up, though. First you need to create symlinks for each of the old
# directory names to this script; then you need to tell the server to follow those symlinks,
# and to execute what it finds there as Perl code. The last bit is the trickiest; here's the
# Apache httpd.conf snippet I used to make it happen:

# <Files ~ ((\.cgi$|^(dorseyssearch|harperschoice|hickoryridge|kingscontrivance|oaklandmills|owenbrown|riverhill|towncenter|wildelake)$))>

# Yeah, that's a long regex. It matches anything ending in CGI, or any of the names in the list
# so long as they're preceded by beginning-of-line and followed by end-of-line; that's so that
# you can have the kingscontrivance symlink in the same directory as a file named 
# kingscontrivance.html, for example, and have the server do the right thing in each instance.

# It's also important to preserve query strings in instances where they exist, which is the
# purpose of all the $ENV{QUERY_STRING} rigamarole below. This way, anything including a GET
# request which goes through this redirector will work properly; I'm not sure about a POST,
# although I suspect that if the browser posts something and gets a Location: header back it
# should do the post again to the url specified in the header. Not sure about that and I don't
# think it matters in this case, so I haven't tested it.

my $name = $ENV{SCRIPT_NAME}; $name =~ s/[^A-Za-z]//g;
my $path = $ENV{PATH_INFO} or '';
my $query = $ENV{QUERY_STRING} or '';
$query = '?' . $query if $query;

print "Location: http://$name.columbiavillages.org$path$query\n\n";