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有人可以解释为什么在创建元框时回调需要通过 $post->ID 传递帖子 id，但是使用动作挂钩“save_post”，函数可以传递 $post_id。关于何时使用哪一个的一般解释有助于解决我一直遇到的一些问题，谢谢。

前任：

function show_custom_meta_box($post) {
    $meta = get_post_meta($post->ID, 'custom_meta_class', true); 
// Use nonce for verification
echo '<input type="hidden" name="custom_meta_box_nonce" value="'.wp_create_nonce(basename(__FILE__)).'" />';

    // Begin the field table and loop
    echo '<table class="form-table">';

        echo '<tr>
                <th><label for="custom-meta-class">Custom Meta Box</label></th>
                <td>
                <input class="widefat" type="text" name="custom-meta-class" id="custom-meta-class" value="'.$meta.'" size="50" />';

        echo '</td></tr>';

    echo '</table>'; // end table
}

对于 $post_id

function save_custom_meta($post) {

    if( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;
    /* Verify the nonce before proceeding. */
    if ( !isset( $_POST['custom_meta_box_nonce'] ) || !wp_verify_nonce( $_POST['custom_meta_box_nonce'], basename( __FILE__ ) ) )
        return $post_id;
    $post_type = get_post_type_object( $post->post_type );
    /* Check if the current user has permission to edit the post. */
    if ( !current_user_can( $post_type->cap->edit_post, $post_id ) )
        return $post_id;
    /* Get the posted data and sanitize it for use as an HTML class. */
    $new_meta_value = ( isset( $_POST['custom-meta-class'] ) ? sanitize_html_class( $_POST['custom-meta-class'] ) : '' );
    /* Get the meta key. */
    $meta_key = 'custom_meta_class';
    /* Get the meta value of the custom field key. */
    $meta_value = get_post_meta( $post_id, $meta_key, true );

    if ( $new_meta_value && '' == $meta_value )
        add_post_meta( $post_id, $meta_key, $new_meta_value, true );

    /* If the new meta value does not match the old value, update it. */
    elseif ( $new_meta_value && $new_meta_value != $meta_value )
        update_post_meta( $post_id, $meta_key, $new_meta_value );

    /* If there is no new meta value but an old value exists, delete it. */
    elseif ( '' == $new_meta_value && $meta_value )
        delete_post_meta( $post_id, $meta_key, $meta_value );
}
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1 回答 1

0

我没有答案，但我有完全相同的问题。我很惊讶在过去的 7 年里没有人参与进来。

这是我的代码，它可以工作（在functions.php中）

add_action('save_post','extract_citations',100,1);
function extract_citations($post_id){
$the_post = get_post($post_id);
$content = $the_post->post_content;
preg_match_all('/<a\s+.*?href=[\"\']?([^\"\' >]*)[\"\']?[^>]*>(.*?)<\/a>/i',$content,$citation_array);
$citation_urls = $citation_array[1];
update_post_meta($post_id,'citations',serialize($citation_urls));
}

尽管理论上是正确的，但这是不起作用的代码：

add_action('save_post','extract_citations',100,1);
function extract_citations($post){
$the_post = get_post($post->ID);
$content = $the_post->post_content;
preg_match_all('/<a\s+.*?href=[\"\']?([^\"\' >]*)[\"\']?[^>]*>(.*?)<\/a>/i',$content,$citation_array);
$citation_urls = $citation_array[1];
update_post_meta($post->ID,'citations',serialize($citation_urls));
}
于 2021-04-19T04:55:17.953 回答