package MyAuth;

sub Authorize {

  $ENV{HTTP_AUTHORIZATION}=~/^Basic (.*)/i ){
  my $up = $1 || '';
  my ($user,$pass)=split(/:/,BASE64_DECODE( $up ),2);

  if( db_query($user,$pass) ){
    $ENV{REMOTE_USER} = $user;
    return "success";
  }else{
    print "Status: 401 Authorization Failed\r\n";
    print "WWW-Authenticate: Basic realm=\"whatever\"\r\n";
    print "Content-type: text/html\r\n\r\n";
    print "Content to be displayed on a canceled login.";
    exit;
  } 
}

##</code><code>##

#!/usr/bin/perl
use MyAuth;
MyAuth::Authorize;
# below this line I am authorized
# do whatever else