wordpress 5.2 之后每一个主题应该使用的动作钩子 wp_body_open

WordPress

这是一个简单的函数，类似于wp_head 和wp_footer 钩子，比如当WordPress开发人员想要插入谷歌分析脚本或任何其他脚本页面前端,可以通过wp_head或wp_footer注入代码：

<?php
function custom_code() {
    return '<!-- some code -->';
}
add_action( 'wp_head', 'custom_code' );
?>

wp_head使用在<head>中，wp_footer使用在</body>前，wp 5.2前没有默认的钩子使用在<body>后以方便的添加代码，WordPress 5.2,新主题结构看起来应该像这样:

<?php // WordPress 5.2 Theme Structure ?>
<html>
  <head>

    ..
    ..

    <?php wp_head(); ?>

  </head>
  <body>

    <?php wp_body_open(); ?>

    ..
    ..

    <?php wp_footer(); ?>

  </body>
</html>

Read more information in related WordPress Trac tickets: #42927, #12563 and #46679.

Updating Themes

If you are a theme developer you should add the newly introduces function to your theme.

Note that some themes have multiple <body> tags, depending on their structure. Those kind of themes should add the wp_body_open() next to the <body> tags.

5.2版本前兼容问题：

<?php
//To support the new function and action in WordPress versions prior to 5.2, you should register the new function by yourself in the theme’s functions.php file: 

<?php
if ( ! function_exists( 'wp_body_open' ) ) {
    /**
     * Fire the wp_body_open action.
     *
     * Added for backwards compatibility to support WordPress versions prior to 5.2.0.
     */
    function wp_body_open() {
        /**
         * Triggered after the opening <body> tag.
         */
        do_action( 'wp_body_open' );
    }
}

Custom Theme Hooks

Many themes use their own custom actions at the beginning of body tag. They should consider migrating to the core wp_body_open action.

For backwards compatibility, when injecting custom code, theme developers can use conditional logic to hook to the right action

<?php
function custom_code() {
    return '<!-- some code -->';
}

if ( did_action( 'wp_body_open' ) ) {
       add_action( 'wp_body_open', 'custom_code' );
    } else {
       add_action( 'custom_theme_hook', 'custom_code' );
}

文章参考：https://generatewp.com/wordpress-5-2-action-that-every-theme-should-use/每每阅读英文文档的时候才觉得英文是多么重要。

理解阅读：