WordPress Post Cloning

clone-posts.php

<?php
/**
 * This file handles the cloning of any post type.
 */

class Clone_Posts {

	/**
	 * Instances of child classes.
	 *
	 * @var array
	 */
	protected static $instances = array();

	/**
	 * Initialization typically happens via get_instance() method.
	 */
	public function __construct() {}

	/**
	 * Return an instance of a child class.
	 *
	 * @return ATT_Singleton
	 */
	public static function get_instance() {
		$class = get_called_class();
		if ( ! isset( self::$instances[ $class ] ) ) {
			self::$instances[ $class ] = new static;
			self::$instances[ $class ]->setup();
		}
		return self::$instances[ $class ];
	}

	/**
	 * Set up the class.
	 */
	protected function setup() {
		add_filter( 'post_row_actions', array( $this, 'post_row_actions' ), 10, 2 );
		add_action( 'admin_post_clone_posts_action', array( $this, 'clone_post' ) );
	}

	/**
	 * Get all of the post types that we will need to clone.
	 *
	 * @return array The post types to clone.
	 */
	function get_post_types() {
		/**
		 * Filter the post types that can be cloned.
		 *
		 * Example:
		 * array(
		 *     'custom-post-type' => array(
		 *         'cap' => 'custom-post-type',          // Used to check for cap.
		 *         'action' => 'clone_custom_post_type', // Used to check for nonce.
		 *     )
		 * ),
		 *
		 * @param array An array of post types.
		 */
		return apply_filters( 'clone_posts_get_post_types_to_clone', array() );
	}

	/**
	 * Add a clone row action to the channel layout list table.
	 *
	 * @param  array  $actions The current list of actions.
	 * @param  object $post    WP_Post object.
	 * @return array  $actions The new list of actions.
	 */
	function post_row_actions( $actions, $post ) {
		foreach ( $this->get_post_types() as $post_type => $args ) {
			if ( $post_type === $post->post_type && current_user_can( 'edit_' . $args['cap'], $post->ID ) ) {
				// Include a nonce in this link
				$clone_link = wp_nonce_url(
					add_query_arg(
						array(
							'action' => 'clone_posts_action',
							'post_type' => $post->post_type,
							'nonce_check' => $args['action'],
						),
						admin_url( 'admin-post.php?post=' . $post->ID )
					),
					$args['action']
				);

				/**
				 * Allow other plugins to determine if this post can have a clone link.
				 *
				 * @param WP_Post $post The current post object.
				 * @param array   $post The current args.
				 */
				if ( apply_filters( 'clone_posts_add_clone_link', true, $post, $args ) ) {
					// Add the clone link to the list of actions.
					$actions = array_merge( $actions, array(
						'copy' => sprintf( '<a href="%1$s">%2$s</a>', esc_url( $clone_link ), esc_html( $this->get_row_action_title() ) ),
					) );
				}
			}
		}
		return $actions;
	}

	/**
	 * Clone a specific post type.  This is called when the use clicks on the clone
	 * row action from the posts list view.
	 */
	function clone_post() {
		if (
			isset( $_GET['post'] )
			&& ! empty( $_GET['nonce_check'] )
			&& check_admin_referer( sanitize_text_field( wp_unslash( $_GET['nonce_check'] ) ) )
		) {
			$post_id = absint( $_GET['post'] );
			$post = get_post( $post_id );

			/**
			 * Can this post be cloned?
			 *
			 * @param WP_Post $post The current post object.
			 */
			if ( ! apply_filters( 'clone_posts_validate_post', true, $post ) ) {
				wp_die( esc_html( __( ' Unable to clone post' ) . ': ' . $post_title ) );
			}

			if ( ! empty( $post_id ) && $post instanceof WP_Post ) {
				$clone_id = wp_insert_post( array(
					'post_status'  => 'draft',
					'post_type'    => $post->post_type,
					'post_title'   => $this->get_cloned_title_prefix() . $post->post_title,
					'post_content' => $post->post_content,
					'post_excerpt' => $post->post_excerpt,
				) );

				// Add all custom fields
				if ( $clone_id ) {
					$custom_fields = get_post_custom( $post_id );
					foreach ( $custom_fields as $meta_key => $custom_field ) {
						foreach ( $custom_field as $meta_value ) {

							/**
							 * Allow other plugins to determine if this meta data
							 * should be added to this post.
							 *
							 * @param int    $clone_id   The cloned post ID.
							 * @param string $meta_key   The meta key.
							 * @param mixed  $meta_value The meta value.
							 */
							if ( apply_filters( 'clone_posts_add_post_meta', true, $clone_id, $meta_key, $meta_value ) ) {
								add_post_meta( $clone_id, $meta_key, maybe_unserialize( $meta_value ) );
							}
						}
					}
				}

				// Add the terms
				$taxonomies = get_post_taxonomies( $post_id );
				foreach ( $taxonomies as $taxonomy ) {
					$terms = get_the_terms( $post_id, $taxonomy );
					if ( ! empty( $terms ) ) {

						/**
						 * Allow other plugins to determine if these terms should
						 * be added to the cloned post.
						 *
						 * @param int    $clone_id The cloned post ID.
						 * @param string $taxonomy The term taxonomy.
						 * @param array  $terms    The terms.
						 */
						if ( apply_filters( 'clone_posts_add_post_terms', true, $clone_id, $taxonomy, $terms ) ) {
							wp_set_object_terms( $clone_id, wp_list_pluck( $terms, 'term_id' ), $taxonomy );
						}
					}
				}
			} // End if().
		} // End if().

		wp_safe_redirect( esc_url_raw( get_admin_url() . '/edit.php?post_type=' . $post->post_type ) );
	}

	/**
	 * Get the cloned post title prefix.
	 *
	 * @return string The cloned title prefix.
	 */
	public function get_cloned_title_prefix() {
		/**
		 * The cloned post title prefix.
		 */
		return apply_filters( 'clone_posts_title_prefix', __( 'CLONED - ' ) );
	}

	/**
	 * Get the row action title.
	 *
	 * @return string The row action title.
	 */
	public function get_row_action_title() {
		/**
		 * The row action title.
		 */
		return apply_filters( 'clone_posts_row_action_title', __( 'Clone' ) );
	}
}

// Start it up!
Clone_Posts::get_instance();

Should be updated to not copy over certain meta data like _edit_lock.