Duplicate Posts and Pages

// Add the duplicate link to action list for post_row_actions

// for "post" and custom post types

add_filter( 'post_row_actions', 'rd_duplicate_post_link', 10, 2 );

// for "page" post type

add_filter( 'page_row_actions', 'rd_duplicate_post_link', 10, 2 );

function rd_duplicate_post_link( $actions, $post ) {

	if( ! current_user_can( 'edit_posts' ) ) {

		return $actions;

	}

	$url = wp_nonce_url(

		add_query_arg(

			array(

				'action' => 'rd_duplicate_post_as_draft',

				'post' => $post->ID,

			),

			'admin.php'

		),

		basename(__FILE__),

		'duplicate_nonce'

	);

	$actions[ 'duplicate' ] = '<a href="' . $url . '" title="Duplicate this item" rel="permalink">Duplicate</a>';

	return $actions;

}

/*

 * Function creates post duplicate as a draft and redirects then to the edit post screen

 */

add_action( 'admin_action_rd_duplicate_post_as_draft', 'rd_duplicate_post_as_draft' );

function rd_duplicate_post_as_draft(){

	// check if post ID has been provided and action

	if ( empty( $_GET[ 'post' ] ) ) {

		wp_die( 'No post to duplicate has been provided!' );

	}

	// Nonce verification

	if ( ! isset( $_GET[ 'duplicate_nonce' ] ) || ! wp_verify_nonce( $_GET[ 'duplicate_nonce' ], basename( __FILE__ ) ) ) {

		return;

	}

	// Get the original post id

	$post_id = absint( $_GET[ 'post' ] );

	// And all the original post data then

	$post = get_post( $post_id );

	/*

	 * if you don't want current user to be the new post author,

	 * then change next couple of lines to this: $new_post_author = $post->post_author;

	 */

	$current_user = wp_get_current_user();

	$new_post_author = $current_user->ID;

	// if post data exists (I am sure it is, but just in a case), create the post duplicate

	if ( $post ) {

		// new post data array

		$args = 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,

			'post_type'      => $post->post_type,

			'to_ping'        => $post->to_ping,

			'menu_order'     => $post->menu_order

		);

		// insert the post by wp_insert_post() function

		$new_post_id = wp_insert_post( $args );

		/*

		 * get all current post terms ad set them to the new post draft

		 */

		$taxonomies = get_object_taxonomies( get_post_type( $post ) ); // returns array of taxonomy names for post type, ex array("category", "post_tag");

		if( $taxonomies ) {

			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 = get_post_meta( $post_id );

		if( $post_meta ) {

			foreach ( $post_meta as $meta_key => $meta_values ) {

				if( '_wp_old_slug' == $meta_key ) { // do nothing for this meta key

					continue;

				}

				foreach ( $meta_values as $meta_value ) {

					add_post_meta( $new_post_id, $meta_key, $meta_value );

				}

			}

		}

		// finally, redirect to the edit post screen for the new draft

		// wp_safe_redirect(

		// 	add_query_arg(

		// 		array(

		// 			'action' => 'edit',

		// 			'post' => $new_post_id

		// 		),

		// 		admin_url( 'post.php' )

		// 	)

		// );

		// exit;

		// or we can redirect to all posts with a message

		wp_safe_redirect(

			add_query_arg(

				array(

					'post_type' => ( 'post' !== get_post_type( $post ) ? get_post_type( $post ) : false ),

					'saved' => 'post_duplication_created' // just a custom slug here

				),

				admin_url( 'edit.php' )

			)

		);

		exit;

	} else {

		wp_die( 'Post creation failed, could not find original post.' );

	}

}

/*

 * In case we decided to add admin notices

 */

add_action( 'admin_notices', 'rudr_duplication_admin_notice' );

function rudr_duplication_admin_notice() {

	// Get the current screen

	$screen = get_current_screen();

	if ( 'edit' !== $screen->base ) {

		return;

	}

    //Checks if settings updated

    if ( isset( $_GET[ 'saved' ] ) && 'post_duplication_created' == $_GET[ 'saved' ] ) {

		 echo '<div class="notice notice-success is-dismissible"><p>Post copy created.</p></div>';

    }

}