function node_wp($post_ID) {
    global $post;
    $post_title = get_the_title( $post_ID );
    $post_url = get_permalink( $post_ID );
    $json = array(
        \'title_post\' => $post_title, 
        \'url\' => $post_url
    );
    $data = json_encode($json); 
    $server_url = get_option(\'$node_server_url_op\');
    ?>
    <script src="<?php echo $server_url; ?>"></script>
    <script type="text/javascript">
        var socket = io.connect(\'<?php echo $server_url; ?>\');
        socket.on(\'connect\', function(){
            socket.emit(\'adduser\');
            socket.emit(\'sendchat\', \'<?php echo $data; ?>\');
        });
    </script>
    <?php
}
add_action(\'publish_post\', \'node_wp\');

运行脚本时，我得到以下信息：

Warning: Cannot modify header information - headers already sent

你能告诉我如何正确添加Javascript吗？