Rich media is an important part of website readability. On a multi-author site, some editors try to save time, or simply forget, and publish posts without setting a featured image. That hurts the user experience to some extent. If we check whether the user has set a featured image before the post is published, and block publishing when it is missing, the problem becomes easy to avoid. In WordPress, this can be implemented very easily.
add_action('save_post', 'wpds_check_thumbnail');
add_action('admin_notices', 'wpds_thumbnail_error');
function wpds_check_thumbnail($post_id) {
// 判断是否为文章
if(get_post_type($post_id) != 'post')
return;
if ( !has_post_thumbnail( $post_id ) ) {
// 设置用户是否设置了图片的临时记录
set_transient( "has_post_thumbnail", "no" );
// 避免循环运行
remove_action('save_post', 'wpds_check_thumbnail');
// 保存文章并设置为草稿
wp_update_post(array('ID' => $post_id, 'post_status' => 'draft'));
add_action('save_post', 'wpds_check_thumbnail');
} else {
delete_transient( "has_post_thumbnail" );
}
}
function wpds_thumbnail_error()
{
// 检查是否设置了特色图像，如果没有设置，显示提示信息
if ( get_transient( "has_post_thumbnail" ) == "no" ) {
echo "<div id='message' class='error'><p><strong>抱歉！发表文章之前，必须先设置一个特色图像！</strong></p></div>";
delete_transient( "has_post_thumbnail" );
}
}Paste the code above into the theme’s functions.php file. The next time an editor tries to publish without a featured image, WordPress will stop the post from being published and show a reminder. Over time, that naturally helps editors build the habit of setting a featured image before publishing.
