#!/usr/local/bin/perl -w

=head1 uri.cgi

Create short URL re-directs, similar to 
www.makeashorterlink.com

=head1 Usage

When passed a valid redirect uri it sends the user
to the appropriate link. When passed an http uri it 
creates a new redirect uri or returns existing one.

  uri.cgi?1062698960 
  uri.cgi?http://www.sfu.ca/~ajdelore/  

=cut

use strict;
use CGI qw (header redirect url);

my $path_to_data = "./.uri_data";

my $uri = $ENV{QUERY_STRING} or &bad_query_string;

if ($uri =~ qr(^\d+$) || $uri =~ qr(^http://)) {

  open (URI_DATA,"+>> $path_to_data");
  my %uri_data;
  while (<URI_DATA>) {
    chomp;
    my ($key,$value) = split;
    $uri_data{$key} = $value;
  }
  if ($uri_data{$uri}) {
    print redirect($uri_data{$uri});
  }
  elsif ($uri =~ qr(^http://)) {
    my %data_uri;
    foreach (keys %uri_data) {
      $data_uri{$uri_data{$_}} = $_;
    }
    my $key = ($data_uri{$uri} || time); 
    print URI_DATA "$key $uri\n";
    print header (-type=>'text/plain');  
    print "The link is ", url, "?$key"
  }
  else { &bad_query_string }
  close URI_DATA;
} 

else { &bad_query_string }

sub bad_query_string {
 print header (-type=>'text/plain');  
 print "Bad query string supplied.\n"; 
 exit;
}