<?php // phpcs:ignore WordPress.Files.FileName.InvalidClassFileName
/**
* Allows viewing posts on the frontend when the user is not logged in.
*
* @package automattic/jetpack
*/
// phpcs:disable WordPress.Security.NonceVerification.Recommended -- This is _implementing_ cross-site nonce handling, no need for WordPress's nonces.
/**
* Allows viewing posts on the frontend when the user is not logged in.
*/
class Jetpack_Frame_Nonce_Preview {
/**
* Static instance.
*
* @todo This should be private.
* @var self
*/
public static $instance = null;
/**
* Returns the single instance of the Jetpack_Frame_Nonce_Preview object
*
* @since 4.3.0
*
* @return Jetpack_Frame_Nonce_Preview
**/
public static function get_instance() {
if ( null === self::$instance ) {
self::$instance = new Jetpack_Frame_Nonce_Preview();
}
return self::$instance;
}
/**
* Constructor.
*
* @todo This should be private.
*/
public function __construct() {
if ( isset( $_GET['frame-nonce'] ) && ! is_admin() ) {
add_filter( 'pre_get_posts', array( $this, 'maybe_display_post' ) );
}
// autosave previews are validated differently.
if ( isset( $_GET['frame-nonce'] ) && isset( $_GET['preview_id'] ) && isset( $_GET['preview_nonce'] ) ) {
remove_action( 'init', '_show_post_preview' );
add_action( 'init', array( $this, 'handle_autosave_nonce_validation' ) );
}
}
/**
* Verify that frame nonce exists, and if so, validate the nonce by calling WP.com.
*
* @since 4.3.0
*
* @return bool
*/
public function is_frame_nonce_valid() {
if ( empty( $_GET['frame-nonce'] ) ) {
return false;
}
$xml = new Jetpack_IXR_Client();
$xml->query( 'jetpack.verifyFrameNonce', sanitize_key( $_GET['frame-nonce'] ) );
if ( $xml->isError() ) {
return false;
}
return (bool) $xml->getResponse();
}
/**
* Conditionally add a hook on posts_results if this is the main query, a preview, and singular.
*
* @since 4.3.0
*
* @param WP_Query $query Query.
* @return WP_Query
*/
public function maybe_display_post( $query ) {
if (
$query->is_main_query() &&
$query->is_preview() &&
$query->is_singular()
) {
add_filter( 'posts_results', array( $this, 'set_post_to_publish' ), 10, 2 );
}
return $query;
}
/**
* Conditionally set the first post to 'publish' if the frame nonce is valid and there is a post.
*
* @since 4.3.0
*
* @param array $posts Posts.
* @return array
*/
public function set_post_to_publish( $posts ) {
remove_filter( 'posts_results', array( $this, 'set_post_to_publish' ), 10, 2 );
if ( empty( $posts ) || is_user_logged_in() || ! $this->is_frame_nonce_valid() ) {
return $posts;
}
$posts[0]->post_status = 'publish';
// Disable comments and pings for this post.
add_filter( 'comments_open', '__return_false' );
add_filter( 'pings_open', '__return_false' );
return $posts;
}
/**
* Handle validation for autosave preview request
*
* @since 4.7.0
*/
public function handle_autosave_nonce_validation() {
if ( ! $this->is_frame_nonce_valid() ) {
wp_die( esc_html__( 'Sorry, you are not allowed to preview drafts.', 'jetpack' ) );
}
add_filter( 'the_preview', '_set_preview' );
}
}
Jetpack_Frame_Nonce_Preview::get_instance();