代码实现wordpress发布文章时检查标题是否重复

/**
 * 发表文章时禁止与已存在的标题相重复
 * Modify from Plugin: Duplicate Title Validate
 * Description: this plugin help , not allow publish Duplicate Title .
 * Author: hasan movahed
 * Reviser: INLOJV
 * Version: 1.0
 * Author URI: http://www.wallfa.com
 * Reviser URI: http://www.inlojv.com
 */


// 发表文章页面，前端抓取标题并使用AJAX发送请求
add_action( 'admin_print_footer_scripts', 'duplicate_titles_enqueue_scripts', 100 );
function duplicate_titles_enqueue_scripts() {
?>
<script>
jQuery(function($){

    function checkTitleAjax(title, id,post_type) {
        var data = {
            action: 'title_checks',
            post_title: title,
            post_type: post_type,
            post_id: id
        };
        $.post(ajaxurl, data, function(response) {
            $('#message').remove();
            $('#poststuff').prepend('<div id="message" class="updated below-h2 fade "><p>'+response+'</p></div>');
        });
    };
    $('#title').change(function() {
        var title = $('#title').val();
        var id = $('#post_ID').val();
        var post_type = $('#post_type').val();
        checkTitleAjax(title, id,post_type);
    });

});
</script>
<?php
}



// 接收前端ajax参数
add_action('wp_ajax_title_checks', 'duplicate_title_checks_callback');
function duplicate_title_checks_callback(){
    global $wpdb;
    $title = $_POST['post_title'];
    $post_id = $_POST['post_id'];
    $titles = "SELECT post_title FROM $wpdb->posts WHERE post_status = 'publish' AND post_type = 'post'
                AND post_title = '{$title}' AND ID != {$post_id} ";
    $results = $wpdb->get_results($titles);
    if($results) {
        echo "<span style='color:red'>". _( '此标题已存在，请换一个标题！' , '' ) ." </span>";
    } else {
        echo '<span style="color:green">'._('恭喜，此标题未与其他文章标题重复！' , '').'</span>';
    }
    die();
}

// 检测后端标题并且避免同名文章更新草稿
add_action( 'publish_post','duplicate_titles_wallfa_bc' ) ;
function duplicate_titles_wallfa_bc( $post ){
    global $wpdb ;
    $title = $_POST['post_title'] ;
    $post_id = $post ;
    $wtitles = "SELECT post_title FROM $wpdb->posts WHERE post_status = 'publish' AND post_type = 'post'
                        AND post_title = '{$title}' AND ID != {$post_id} " ;
    $wresults = $wpdb->get_results( $wtitles ) ;
    if ( $wresults ){
        $wpdb->update( $wpdb->posts, array( 'post_status' =>
                'draft' ), array( 'ID' => $post ) ) ;
        $arr_params = array( 'message' => '10', 'wallfaerror' => '1' )  ;
        $location = add_query_arg( $arr_params , get_edit_post_link( $post , 'url' ) ) ;
        wp_redirect( $location  ) ;
        exit ;
    }
}



/// 文章提交更新后的提示
add_action( 'admin_notices', 'not_published_error_notice' );
function not_published_error_notice() {
    if(isset($_GET['wallfaerror']) == 1 ){
       ?>
       <div class="updated">
       <p style='color:red' ><?php _e('貌似已经存在相同标题的文章，若您使用了文章别名作为固定链接，则可以通过修改本文的固定链接来使标题不再重复！' , '') ?></p>
       </div>
       <?php
    }
}



// 禁用自动保存
add_action( 'wp_print_scripts', 'disable_autosave' ) ;
function disable_autosave(){
    wp_deregister_script( 'autosave' ) ;
}