name : theme-previews.php <?php /** * Theme previews using the Site Editor for block themes. * * @package WordPress */ /** * Filters the blog option to return the path for the previewed theme. * * @since 6.3.0 * * @param string $current_stylesheet The current theme's stylesheet or template path. * @return string The previewed theme's stylesheet or template path. */ function wp_get_theme_preview_path( $current_stylesheet = null ) { if ( ! current_user_can( 'switch_themes' ) ) { return $current_stylesheet; } $preview_stylesheet = ! empty( $_GET['wp_theme_preview'] ) ? sanitize_text_field( wp_unslash( $_GET['wp_theme_preview'] ) ) : null; $wp_theme = wp_get_theme( $preview_stylesheet ); if ( ! is_wp_error( $wp_theme->errors() ) ) { if ( current_filter() === 'template' ) { $theme_path = $wp_theme->get_template(); } else { $theme_path = $wp_theme->get_stylesheet(); } return sanitize_text_field( $theme_path ); } return $current_stylesheet; } /** * Adds a middleware to `apiFetch` to set the theme for the preview. * This adds a `wp_theme_preview` URL parameter to API requests from the Site Editor, so they also respond as if the theme is set to the value of the parameter. * * @since 6.3.0 */ function wp_attach_theme_preview_middleware() { // Don't allow non-admins to preview themes. if ( ! current_user_can( 'switch_themes' ) ) { return; } wp_add_inline_script( 'wp-api-fetch', sprintf( 'wp.apiFetch.use( wp.apiFetch.createThemePreviewMiddleware( %s ) );', wp_json_encode( sanitize_text_field( wp_unslash( $_GET['wp_theme_preview'] ) ) ) ), 'after' ); } /** * Set a JavaScript constant for theme activation. * * Sets the JavaScript global WP_BLOCK_THEME_ACTIVATE_NONCE containing the nonce * required to activate a theme. For use within the site editor. * * @see https://github.com/WordPress/gutenberg/pull/41836 * * @since 6.3.0 * @access private */ function wp_block_theme_activate_nonce() { $nonce_handle = 'switch-theme_' . wp_get_theme_preview_path(); ?> <script type="text/javascript"> window.WP_BLOCK_THEME_ACTIVATE_NONCE = <?php echo wp_json_encode( wp_create_nonce( $nonce_handle ) ); ?>; </script> <?php } /** * Add filters and actions to enable Block Theme Previews in the Site Editor. * * The filters and actions should be added after `pluggable.php` is included as they may * trigger code that uses `current_user_can()` which requires functionality from `pluggable.php`. * * @since 6.3.2 */ function wp_initialize_theme_preview_hooks() { if ( ! empty( $_GET['wp_theme_preview'] ) ) { add_filter( 'stylesheet', 'wp_get_theme_preview_path' ); add_filter( 'template', 'wp_get_theme_preview_path' ); add_action( 'init', 'wp_attach_theme_preview_middleware' ); add_action( 'admin_head', 'wp_block_theme_activate_nonce' ); } }