duplicate_post_as_draft()

        public function duplicate_post_as_draft(){
            global $wpdb;

            if ( !(isset($this->super->get['post']) || isset($this->super->post['post']) || (isset($this->super->request['action']) && $this->super->request['action'] === 'duplicate_post_as_draft')) ){
                wp_die('No post to duplicate has been supplied!');
            }

            $post_id = ( isset($this->super->get['post'] )? intval($this->super->get['post']) : intval($this->super->post['post'])); //Get the original post id
            $post = get_post($post_id); //Get all the original post data

            $current_user = wp_get_current_user();
            $new_post_author = $current_user->ID; //Set post author (default by current user). For original author change to: $new_post_author = $post->post_author;

            //If post data exists, create the post duplicate
            if ( isset($post) && $post != null ){

                //Insert the post by wp_insert_post() function
                $new_post_id = wp_insert_post(array(
                    'comment_status' => $post->comment_status,
                    'ping_status' => $post->ping_status,
                    'post_author' => $new_post_author,
                    'post_content' => $post->post_content,
                    'post_excerpt' => $post->post_excerpt,
                    'post_name' => $post->post_name,
                    'post_parent' => $post->post_parent,
                    'post_password' => $post->post_password,
                    'post_status' => 'draft',
                    'post_title' => $post->post_title . ' copy',
                    'post_type' => $post->post_type,
                    'to_ping' => $post->to_ping,
                    'menu_order' => $post->menu_order
                ));

                //Get all current post terms ad set them to the new post draft
                $taxonomies = get_object_taxonomies($post->post_type); //returns array of taxonomy names for post type, ex array("category", "post_tag");
                foreach ( $taxonomies as $taxonomy ){
                    $post_terms = wp_get_object_terms($post_id, $taxonomy, array('fields' => 'slugs'));
                    wp_set_object_terms($new_post_id, $post_terms, $taxonomy, false);
                }

                //Duplicate all post meta
                $post_meta_infos = $wpdb->get_results("SELECT meta_key, meta_value FROM $wpdb->postmeta WHERE post_id=$post_id"); //DB Query
                if ( count($post_meta_infos) !== 0 ){
                    $sql_query = "INSERT INTO $wpdb->postmeta (post_id, meta_key, meta_value) ";
                    foreach ( $post_meta_infos as $meta_info ){
                        $meta_key = $meta_info->meta_key;
                        $meta_value = addslashes($meta_info->meta_value);
                        $sql_query_sel[] = "SELECT $new_post_id, '$meta_key', '$meta_value'";
                    }
                    $sql_query .= implode(" UNION ALL ", $sql_query_sel);
                    $wpdb->query($sql_query); //DB Query
                }

                wp_redirect(admin_url('post.php?action=edit&post=' . $new_post_id)); //Redirect to the edit post screen for the new draft
                exit;
            } else {
                wp_die('Post creation failed, could not find original post: ' . $post_id);
            }
        }