switch($proxy_type){
        case 'SQUID' {
            $web_proxy = $proxy_address;
        }
        case 'EZPROXY' {
            if ($proxy_credentials){
                ($user_name, $password) =
                split /\//, $proxy_credentials;
                $prefix =
                $proxy_address."user=$user_name&pass=$password&url="
;   
            }
            else {
                $prefix = $proxy_address."url=";
            }
        }
    }