[Summary view] [Print] [Text view]

   1  <?php
   2  /**
   3   * Theme previews using the Site Editor for block themes.
   4   *
   5   * @package WordPress
   6   */
   7  
   8  /**
   9   * Filters the blog option to return the path for the previewed theme.
  10   *
  11   * @since 6.3.0
  12   *
  13   * @param string $current_stylesheet The current theme's stylesheet or template path.
  14   * @return string The previewed theme's stylesheet or template path.
  15   */
  16  function wp_get_theme_preview_path( $current_stylesheet = null ) {
  17      if ( ! current_user_can( 'switch_themes' ) ) {
  18          return $current_stylesheet;
  19      }
  20  
  21      $preview_stylesheet = ! empty( $_GET['wp_theme_preview'] ) ? sanitize_text_field( wp_unslash( $_GET['wp_theme_preview'] ) ) : null;
  22      $wp_theme           = wp_get_theme( $preview_stylesheet );
  23      if ( ! is_wp_error( $wp_theme->errors() ) ) {
  24          if ( current_filter() === 'template' ) {
  25              $theme_path = $wp_theme->get_template();
  26          } else {
  27              $theme_path = $wp_theme->get_stylesheet();
  28          }
  29  
  30          return sanitize_text_field( $theme_path );
  31      }
  32  
  33      return $current_stylesheet;
  34  }
  35  
  36  /**
  37   * Adds a middleware to `apiFetch` to set the theme for the preview.
  38   * 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.
  39   *
  40   * @since 6.3.0
  41   */
  42  function wp_attach_theme_preview_middleware() {
  43      // Don't allow non-admins to preview themes.
  44      if ( ! current_user_can( 'switch_themes' ) ) {
  45          return;
  46      }
  47  
  48      wp_add_inline_script(
  49          'wp-api-fetch',
  50          sprintf(
  51              'wp.apiFetch.use( wp.apiFetch.createThemePreviewMiddleware( %s ) );',
  52              wp_json_encode( sanitize_text_field( wp_unslash( $_GET['wp_theme_preview'] ) ) )
  53          ),
  54          'after'
  55      );
  56  }
  57  
  58  /**
  59   * Set a JavaScript constant for theme activation.
  60   *
  61   * Sets the JavaScript global WP_BLOCK_THEME_ACTIVATE_NONCE containing the nonce
  62   * required to activate a theme. For use within the site editor.
  63   *
  64   * @see https://github.com/WordPress/gutenberg/pull/41836
  65   *
  66   * @since 6.3.0
  67   * @access private
  68   */
  69  function wp_block_theme_activate_nonce() {
  70      $nonce_handle = 'switch-theme_' . wp_get_theme_preview_path();
  71      ?>
  72      <script type="text/javascript">
  73          window.WP_BLOCK_THEME_ACTIVATE_NONCE = <?php echo wp_json_encode( wp_create_nonce( $nonce_handle ) ); ?>;
  74      </script>
  75      <?php
  76  }
  77  
  78  /**
  79   * Add filters and actions to enable Block Theme Previews in the Site Editor.
  80   *
  81   * The filters and actions should be added after `pluggable.php` is included as they may
  82   * trigger code that uses `current_user_can()` which requires functionality from `pluggable.php`.
  83   *
  84   * @since 6.3.2
  85   */
  86  function wp_initialize_theme_preview_hooks() {
  87      if ( ! empty( $_GET['wp_theme_preview'] ) ) {
  88          add_filter( 'stylesheet', 'wp_get_theme_preview_path' );
  89          add_filter( 'template', 'wp_get_theme_preview_path' );
  90          add_action( 'init', 'wp_attach_theme_preview_middleware' );
  91          add_action( 'admin_head', 'wp_block_theme_activate_nonce' );
  92      }
  93  }