class.frame-nonce-preview.php
| 1 | <?php |
| 2 | |
| 3 | /** |
| 4 | * Allows viewing posts on the frontend when the user is not logged in. |
| 5 | */ |
| 6 | class Jetpack_Frame_Nonce_Preview { |
| 7 | static $instance = null; |
| 8 | |
| 9 | /** |
| 10 | * Returns the single instance of the Jetpack_Frame_Nonce_Preview object |
| 11 | * |
| 12 | * @since 4.3.0 |
| 13 | * |
| 14 | * @return Jetpack_Frame_Nonce_Preview |
| 15 | **/ |
| 16 | public static function get_instance() { |
| 17 | if ( ! is_null( self::$instance ) ) { |
| 18 | return self::$instance; |
| 19 | } |
| 20 | |
| 21 | return self::$instance = new Jetpack_Frame_Nonce_Preview(); |
| 22 | } |
| 23 | |
| 24 | function __construct() { |
| 25 | if ( isset( $_GET['frame-nonce'] ) && ! is_admin() ) { |
| 26 | add_filter( 'pre_get_posts', array( $this, 'maybe_display_post' ) ); |
| 27 | } |
| 28 | |
| 29 | // autosave previews are validated differently |
| 30 | if ( isset( $_GET['frame-nonce'] ) && isset( $_GET['preview_id'] ) && isset( $_GET['preview_nonce'] ) ) { |
| 31 | remove_action( 'init', '_show_post_preview' ); |
| 32 | add_action( 'init', array( $this, 'handle_autosave_nonce_validation' ) ); |
| 33 | } |
| 34 | } |
| 35 | |
| 36 | /** |
| 37 | * Verify that frame nonce exists, and if so, validate the nonce by calling WP.com. |
| 38 | * |
| 39 | * @since 4.3.0 |
| 40 | * |
| 41 | * @return bool |
| 42 | */ |
| 43 | public function is_frame_nonce_valid() { |
| 44 | if ( empty( $_GET['frame-nonce'] ) ) { |
| 45 | return false; |
| 46 | } |
| 47 | |
| 48 | $xml = new Jetpack_IXR_Client(); |
| 49 | $xml->query( 'jetpack.verifyFrameNonce', sanitize_key( $_GET['frame-nonce'] ) ); |
| 50 | |
| 51 | if ( $xml->isError() ) { |
| 52 | return false; |
| 53 | } |
| 54 | |
| 55 | return (bool) $xml->getResponse(); |
| 56 | } |
| 57 | |
| 58 | /** |
| 59 | * Conditionally add a hook on posts_results if this is the main query, a preview, and singular. |
| 60 | * |
| 61 | * @since 4.3.0 |
| 62 | * |
| 63 | * @param WP_Query $query |
| 64 | * |
| 65 | * @return WP_Query |
| 66 | */ |
| 67 | public function maybe_display_post( $query ) { |
| 68 | if ( |
| 69 | $query->is_main_query() && |
| 70 | $query->is_preview() && |
| 71 | $query->is_singular() |
| 72 | ) { |
| 73 | add_filter( 'posts_results', array( $this, 'set_post_to_publish' ), 10, 2 ); |
| 74 | } |
| 75 | |
| 76 | return $query; |
| 77 | } |
| 78 | |
| 79 | /** |
| 80 | * Conditionally set the first post to 'publish' if the frame nonce is valid and there is a post. |
| 81 | * |
| 82 | * @since 4.3.0 |
| 83 | * |
| 84 | * @param array $posts |
| 85 | * |
| 86 | * @return array |
| 87 | */ |
| 88 | public function set_post_to_publish( $posts ) { |
| 89 | remove_filter( 'posts_results', array( $this, 'set_post_to_publish' ), 10, 2 ); |
| 90 | |
| 91 | if ( empty( $posts ) || is_user_logged_in() || ! $this->is_frame_nonce_valid() ) { |
| 92 | return $posts; |
| 93 | } |
| 94 | |
| 95 | $posts[0]->post_status = 'publish'; |
| 96 | |
| 97 | // Disable comments and pings for this post. |
| 98 | add_filter( 'comments_open', '__return_false' ); |
| 99 | add_filter( 'pings_open', '__return_false' ); |
| 100 | |
| 101 | return $posts; |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Handle validation for autosave preview request |
| 106 | * |
| 107 | * @since 4.7.0 |
| 108 | */ |
| 109 | public function handle_autosave_nonce_validation() { |
| 110 | if ( ! $this->is_frame_nonce_valid() ) { |
| 111 | wp_die( __( 'Sorry, you are not allowed to preview drafts.', 'jetpack' ) ); |
| 112 | } |
| 113 | add_filter( 'the_preview', '_set_preview' ); |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | Jetpack_Frame_Nonce_Preview::get_instance(); |
| 118 |