jetpack / class.frame-nonce-preview.php

class.frame-nonce-preview.php in Jetpack – WP Security, Backup, Speed, & Growth 12.1, at class.frame-nonce-preview.php

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1	<?php // phpcs:ignore WordPress.Files.FileName.InvalidClassFileName
2	/**
3	* Allows viewing posts on the frontend when the user is not logged in.
4	*
5	* @package automattic/jetpack
6	*/
7
8	// phpcs:disable WordPress.Security.NonceVerification.Recommended -- This is _implementing_ cross-site nonce handling, no need for WordPress's nonces.
9
10	/**
11	* Allows viewing posts on the frontend when the user is not logged in.
12	*/
13	class Jetpack_Frame_Nonce_Preview {
14	/**
15	* Static instance.
16	*
17	* @todo This should be private.
18	* @var self
19	*/
20	public static $instance = null;
21
22	/**
23	* Returns the single instance of the Jetpack_Frame_Nonce_Preview object
24	*
25	* @since 4.3.0
26	*
27	* @return Jetpack_Frame_Nonce_Preview
28	**/
29	public static function get_instance() {
30	if ( null === self::$instance ) {
31	self::$instance = new Jetpack_Frame_Nonce_Preview();
32	}
33
34	return self::$instance;
35	}
36
37	/**
38	* Constructor.
39	*
40	* @todo This should be private.
41	*/
42	public function __construct() {
43	if ( isset( $_GET['frame-nonce'] ) && ! is_admin() ) {
44	add_filter( 'pre_get_posts', array( $this, 'maybe_display_post' ) );
45	}
46
47	// autosave previews are validated differently.
48	if ( isset( $_GET['frame-nonce'] ) && isset( $_GET['preview_id'] ) && isset( $_GET['preview_nonce'] ) ) {
49	remove_action( 'init', '_show_post_preview' );
50	add_action( 'init', array( $this, 'handle_autosave_nonce_validation' ) );
51	}
52	}
53
54	/**
55	* Verify that frame nonce exists, and if so, validate the nonce by calling WP.com.
56	*
57	* @since 4.3.0
58	*
59	* @return bool
60	*/
61	public function is_frame_nonce_valid() {
62	if ( empty( $_GET['frame-nonce'] ) ) {
63	return false;
64	}
65
66	$xml = new Jetpack_IXR_Client();
67	$xml->query( 'jetpack.verifyFrameNonce', sanitize_key( $_GET['frame-nonce'] ) );
68
69	if ( $xml->isError() ) {
70	return false;
71	}
72
73	return (bool) $xml->getResponse();
74	}
75
76	/**
77	* Conditionally add a hook on posts_results if this is the main query, a preview, and singular.
78	*
79	* @since 4.3.0
80	*
81	* @param WP_Query $query Query.
82	* @return WP_Query
83	*/
84	public function maybe_display_post( $query ) {
85	if (
86	$query->is_main_query() &&
87	$query->is_preview() &&
88	$query->is_singular()
89	) {
90	add_filter( 'posts_results', array( $this, 'set_post_to_publish' ), 10, 2 );
91	}
92
93	return $query;
94	}
95
96	/**
97	* Conditionally set the first post to 'publish' if the frame nonce is valid and there is a post.
98	*
99	* @since 4.3.0
100	*
101	* @param array $posts Posts.
102	* @return array
103	*/
104	public function set_post_to_publish( $posts ) {
105	remove_filter( 'posts_results', array( $this, 'set_post_to_publish' ), 10, 2 );
106
107	if ( empty( $posts ) \|\| is_user_logged_in() \|\| ! $this->is_frame_nonce_valid() ) {
108	return $posts;
109	}
110
111	$posts[0]->post_status = 'publish';
112
113	// Disable comments and pings for this post.
114	add_filter( 'comments_open', '__return_false' );
115	add_filter( 'pings_open', '__return_false' );
116
117	return $posts;
118	}
119
120	/**
121	* Handle validation for autosave preview request
122	*
123	* @since 4.7.0
124	*/
125	public function handle_autosave_nonce_validation() {
126	if ( ! $this->is_frame_nonce_valid() ) {
127	wp_die( esc_html__( 'Sorry, you are not allowed to preview drafts.', 'jetpack' ) );
128	}
129	add_filter( 'the_preview', '_set_preview' );
130	}
131	}
132
133	Jetpack_Frame_Nonce_Preview::get_instance();
134