1/**
  2 * Duplicate WordPress Posts, Pages, and Custom Post Types as Drafts
  3 *
  4 * This code snippet enables the duplication of WordPress posts, pages, and all registered custom post types (CPTs).
  5 * It adds a 'Duplicate' link to the row actions for each item in the admin dashboard. When clicked, this link
  6 * triggers the duplication of the selected item, creating a new draft with the same content, custom fields,
  7 * and taxonomies.
  8 *
  9 * Functions:
 10 * 1. `duplicate_post_as_draft`: Handles the duplication process. It copies the post data, including title,
 11 *    content, excerpt, and custom fields, and creates a new post with a 'draft' status. It also maintains
 12 *    the taxonomy terms (like categories and tags) from the original post.
 13 * 2. `duplicate_post_link`: Adds the 'Duplicate' action link to the WordPress admin interface for each post,
 14 *    page, and custom post type. This link uses WordPress's built-in nonce functionality for security.
 15 * 3. `apply_duplicate_post_link_to_cpts`: Dynamically applies the duplicate post link function to all public
 16 *    post types, ensuring the 'Duplicate' link appears for any custom post types registered on the site.
 17 *
 18 * Author: Mark Harris
 19 * URI: https://www.christchurchwebsolutions.co.uk
 20 */
 21 
 22function duplicate_post_as_draft() {
 23    global $wpdb;
 24 
 25    // Verify the nonce for security
 26    $nonce_action = 'duplicate_post_as_draft';
 27    $nonce_name = 'duplicate_nonce';
 28    if (!isset($_GET[$nonce_name]) || !wp_verify_nonce($_GET[$nonce_name], $nonce_action)) {
 29        wp_die(esc_html__('Security check failed.', 'wpturbo'));
 30    }
 31 
 32    // Check if the 'post' parameter is set in either GET or POST request
 33    $post_id = filter_input(INPUT_GET, 'post', FILTER_SANITIZE_NUMBER_INT) ?: filter_input(INPUT_POST, 'post', FILTER_SANITIZE_NUMBER_INT);
 34 
 35    if (!$post_id) {
 36        wp_die(esc_html__('No post to duplicate has been supplied!', 'wpturbo'));
 37    }
 38 
 39    // Check if the post exists
 40    $post = get_post($post_id);
 41    if (!$post) {
 42        wp_die(esc_html(sprintf(__('Post creation failed, could not find original post: %s', 'wpturbo'), $post_id)));
 43    }
 44 
 45    $current_user = wp_get_current_user();
 46    $new_post_author = $current_user->ID;
 47 
 48    $args = [
 49        "comment_status" => $post->comment_status,
 50        "ping_status" => $post->ping_status,
 51        "post_author" => $new_post_author,
 52        "post_content" => $post->post_content,
 53        "post_excerpt" => $post->post_excerpt,
 54        "post_name" => $post->post_name,
 55        "post_parent" => $post->post_parent,
 56        "post_password" => $post->post_password,
 57        "post_status" => "draft",
 58        "post_title" => $post->post_title . " (Copy)",
 59        "post_type" => $post->post_type,
 60        "to_ping" => $post->to_ping,
 61        "menu_order" => $post->menu_order
 62    ];
 63 
 64    $new_post_id = wp_insert_post($args);
 65 
 66    $taxonomies = get_object_taxonomies($post->post_type);
 67    foreach ($taxonomies as $taxonomy) {
 68        $post_terms = wp_get_object_terms($post_id, $taxonomy, ["fields" => "slugs"]);
 69        wp_set_object_terms($new_post_id, $post_terms, $taxonomy, false);
 70    }
 71 
 72    $post_meta_infos = $wpdb->get_results(
 73        $wpdb->prepare("SELECT meta_key, meta_value FROM $wpdb->postmeta WHERE post_id = %d", $post_id)
 74    );
 75    if (count($post_meta_infos) != 0) {
 76        foreach ($post_meta_infos as $meta_info) {
 77            $meta_key = $meta_info->meta_key;
 78            $meta_value = sanitize_meta($meta_info->meta_key, $meta_info->meta_value, "post");
 79            $wpdb->insert($wpdb->postmeta, [
 80                "post_id" => $new_post_id,
 81                "meta_key" => $meta_key,
 82                "meta_value" => $meta_value
 83            ]);
 84        }
 85    }
 86 
 87    // Redirect to the post list screen and show a success message
 88    $redirect_url = admin_url("edit.php?post_type=" . $post->post_type);
 89    wp_redirect(add_query_arg("message", "101", $redirect_url));
 90    exit();
 91}
 92 
 93add_action("admin_action_duplicate_post_as_draft", "duplicate_post_as_draft");
 94 
 95function duplicate_post_link($actions, $post) {
 96    if (current_user_can('edit_posts')) {
 97        $actions['duplicate'] = '<a href="' .
 98            wp_nonce_url(
 99                admin_url("admin.php?action=duplicate_post_as_draft&post=" . $post->ID),
100                'duplicate_post_as_draft',
101                'duplicate_nonce'
102            ) .
103            '" title="' . esc_attr__('Duplicate this item', 'wpturbo') .
104            '" rel="permalink">' . esc_html__('Duplicate', 'wpturbo') . '</a>';
105    }
106    return $actions;
107}
108 
109add_filter("post_row_actions", "duplicate_post_link", 10, 2);
110add_filter("page_row_actions", "duplicate_post_link", 10, 2);
111 
112function apply_duplicate_post_link_to_cpts() {
113    $post_types = get_post_types(["public" => true], "names");
114    foreach ($post_types as $post_type) {
115        add_filter("{$post_type}_row_actions", "duplicate_post_link", 10, 2);
116    }
117}
118 
119add_action("admin_init", "apply_duplicate_post_link_to_cpts");
120 
121function show_duplicate_admin_notice() {
122    if (isset($_GET['message']) && $_GET['message'] === '101') {
123        echo '<div class="notice notice-success is-dismissible"><p>' . esc_html('Post duplicated successfully.') . '</p></div>';
124    }
125}
126 
127add_action('admin_notices', 'show_duplicate_admin_notice');