# handshake
if( my $key = $ENV{HTTP_SEC_WEBSOCKET_KEY} ){
    $key .= '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'; # WTF
    $key = Digest::SHA::sha1($key);
    $key = MIME::Base64::encode_base64($key);
    $key =~ s{\s+}{}g;

    print "HTTP/1.1 101 WebSocket Protocol Handshake\n";
    print "Sec-WebSocket-Accept: $key\n";
    print "Connection: Upgrade, Keep-Alive \n";
    print "Upgrade: WebSocket\n";
}