<?php
/**
* Extend WordPress core's rendering of menus to support block-based menus.
*
* @package gutenberg
*/
/**
* Shim that hooks into `wp_update_nav_menu_item` and makes it so that nav menu
* items support a 'content' field. This field contains HTML and is used by nav
* menu items with `type` set to `'block'`.
*
* Specifically, this shim makes it so that:
*
* 1) The `wp_update_nav_menu_item()` function supports setting
* `'menu-item-content'` on a menu item. When merged to Core, this functionality
* should exist in `wp_update_nav_menu_item()`.
*
* 2) Updating a menu via nav-menus.php supports setting `'menu-item-content'`
* on a menu item. When merged to Core, this functionality should exist in
* `wp_nav_menu_update_menu_items()`.
*
* 3) The `customize_save` ajax action supports setting `'content'` on a nav
* menu item. When merged to Core, this functionality should exist in
* `WP_Customize_Manager::save()`.
*
* This shim can be removed when the Gutenberg plugin requires a WordPress
* version that has the ticket below.
*
* @see https://core.trac.wordpress.org/ticket/50544
*
* @param int $menu_id ID of the updated menu.
* @param int $menu_item_db_id ID of the new menu item.
* @param array $args An array of arguments used to update/add the menu item.
*/
function gutenberg_update_nav_menu_item_content( $menu_id, $menu_item_db_id, $args ) {
global $wp_customize;
// Support setting content in nav-menus.php by grabbing the value from
// $_POST. This belongs in `wp_nav_menu_update_menu_items()`.
if ( isset( $_POST['menu-item-content'][ $menu_item_db_id ] ) ) {
$args['menu-item-content'] = wp_unslash( $_POST['menu-item-content'][ $menu_item_db_id ] );
}
// Support setting content in customize_save admin-ajax.php requests by
// grabbing the unsanitized $_POST values. This belongs in
// `WP_Customize_Manager::save()`.
if ( isset( $wp_customize ) ) {
$values = $wp_customize->unsanitized_post_values();
if ( isset( $values[ "nav_menu_item[$menu_item_db_id]" ]['content'] ) ) {
if ( is_string( $values[ "nav_menu_item[$menu_item_db_id]" ]['content'] ) ) {
$args['menu-item-content'] = $values[ "nav_menu_item[$menu_item_db_id]" ]['content'];
} elseif ( isset( $values[ "nav_menu_item[$menu_item_db_id]" ]['content']['raw'] ) ) {
$args['menu-item-content'] = $values[ "nav_menu_item[$menu_item_db_id]" ]['content']['raw'];
}
}
}
// Everything else belongs in `wp_update_nav_menu_item()`.
$defaults = array(
'menu-item-content' => '',
);
$args = wp_parse_args( $args, $defaults );
update_post_meta( $menu_item_db_id, '_menu_item_content', wp_slash( $args['menu-item-content'] ) );
}
add_action( 'wp_update_nav_menu_item', 'gutenberg_update_nav_menu_item_content', 10, 3 );
/**
* Shim that hooks into `wp_setup_nav_menu_items` and makes it so that nav menu
* items have a 'content' field. This field contains HTML and is used by nav
* menu items with `type` set to `'block'`.
*
* Specifically, this shim makes it so that the `wp_setup_nav_menu_item()`
* function sets `content` on the returned menu item. When merged to Core, this
* functionality should exist in `wp_setup_nav_menu_item()`.
*
* This shim can be removed when the Gutenberg plugin requires a WordPress
* version that has the ticket below.
*
* @see https://core.trac.wordpress.org/ticket/50544
*
* @param object $menu_item The menu item object.
*
* @return object Updated menu item object.
*/
function gutenberg_setup_block_nav_menu_item( $menu_item ) {
if ( 'block' === $menu_item->type ) {
$menu_item->type_label = __( 'Block', 'gutenberg' );
$menu_item->content = ! isset( $menu_item->content ) ? get_post_meta( $menu_item->db_id, '_menu_item_content', true ) : $menu_item->content;
// Set to make the menu item display nicely in nav-menus.php.
$menu_item->object = 'block';
$menu_item->title = __( 'Block', 'gutenberg' );
}
return $menu_item;
}
add_filter( 'wp_setup_nav_menu_item', 'gutenberg_setup_block_nav_menu_item' );
/**
* Shim that hooks into `walker_nav_menu_start_el` and makes it so that the
* default walker which renders a menu will correctly render the HTML associated
* with any navigation menu item that has `type` set to `'block`'.
*
* Specifically, this shim makes it so that `Walker_Nav_Menu::start_el()`
* renders the `content` of a nav menu item when its `type` is `'block'`. When
* merged to Core, this functionality should exist in
* `Walker_Nav_Menu::start_el()`.
*
* This shim can be removed when the Gutenberg plugin requires a WordPress
* version that has the ticket below.
*
* @see https://core.trac.wordpress.org/ticket/50544
*
* @param string $item_output The menu item's starting HTML output.
* @param WP_Post $item Menu item data object.
* @param int $depth Depth of menu item. Used for padding.
* @param stdClass $args An object of wp_nav_menu() arguments.
*
* @return string The menu item's updated HTML output.
*/
function gutenberg_output_block_nav_menu_item( $item_output, $item, $depth, $args ) {
if ( 'block' === $item->type ) {
$item_output = $args->before;
/** This filter is documented in wp-includes/post-template.php */
$item_output .= apply_filters( 'the_content', $item->content );
$item_output .= $args->after;
}
return $item_output;
}
add_filter( 'walker_nav_menu_start_el', 'gutenberg_output_block_nav_menu_item', 10, 4 );
/**
* Shim that prevents menu items with type `'block'` from being rendered in the
* frontend when the theme does not support block menus.
*
* Specifically, this shim makes it so that `wp_nav_menu()` will remove any menu
* items that have a `type` of `'block'` from `$sorted_menu_items`. When merged
* to Core, this functionality should exist in `wp_nav_menu()`.
*
* This shim can be removed when the Gutenberg plugin requires a WordPress
* version that has the ticket below.
*
* @see https://core.trac.wordpress.org/ticket/50544
*
* @param array $menu_items The menu items, sorted by each menu item's menu order.
*
* @return array Updated menu items, sorted by each menu item's menu order.
*/
function gutenberg_remove_block_nav_menu_items( $menu_items ) {
// We should uncomment the line below when the block-nav-menus feature becomes stable.
// @see https://github.com/WordPress/gutenberg/issues/34265.
/*if ( current_theme_supports( 'block-nav-menus' ) ) {*/
if ( false ) {
return $menu_items;
}
return array_filter(
$menu_items,
static function ( $menu_item ) {
return 'block' !== $menu_item->type;
}
);
}
add_filter( 'wp_nav_menu_objects', 'gutenberg_remove_block_nav_menu_items', 10 );
/**
* Recursively converts a list of menu items into a list of blocks. This is a
* helper function used by `gutenberg_output_block_nav_menu()`.
*
* Transformation depends on the menu item type. Link menu items are turned into
* a `core/navigation-link` block. Block menu items are simply parsed.
*
* @param array $menu_items The menu items to convert, sorted by each menu item's menu order.
* @param array $menu_items_by_parent_id All menu items, indexed by their parent's ID.
* @return array Updated menu items, sorted by each menu item's menu order.
*/
function gutenberg_convert_menu_items_to_blocks(
$menu_items,
&$menu_items_by_parent_id
) {
if ( empty( $menu_items ) ) {
return array();
}
$blocks = array();
foreach ( $menu_items as $menu_item ) {
if ( 'block' === $menu_item->type ) {
$parsed_blocks = parse_blocks( $menu_item->content );
if ( count( $parsed_blocks ) ) {
$block = $parsed_blocks[0];
} else {
$block = array(
'blockName' => 'core/freeform',
'attrs' => array(
'originalContent' => $menu_item->content,
),
);
}
} else {
$block = array(
'blockName' => 'core/navigation-link',
'attrs' => array(
'label' => $menu_item->title,
'url' => $menu_item->url,
),
);
}
$block['innerBlocks'] = gutenberg_convert_menu_items_to_blocks(
isset( $menu_items_by_parent_id[ $menu_item->ID ] )
? $menu_items_by_parent_id[ $menu_item->ID ]
: array(),
$menu_items_by_parent_id
);
$blocks[] = $block;
}
return $blocks;
}
/**
* Shim that causes `wp_nav_menu()` to output a Navigation block instead of a
* nav menu when the theme supports block menus. The Navigation block is
* constructed by transforming the stored tree of menu items into a tree of
* blocks.
*
* Specifically, this shim makes it so that `wp_nav_menu()` returns early when
* the theme supports block menus. When merged to Core, this functionality
* should exist in `wp_nav_menu()` after `$sorted_menu_items` is set. The
* duplicated code (marked using BEGIN and END) can be deleted.
*
* This shim can be removed when the Gutenberg plugin requires a WordPress
* version that has the ticket below.
*
* @see https://core.trac.wordpress.org/ticket/50544
*
* @param string|null $output Nav menu output to short-circuit with. Default null.
* @param stdClass $args An object containing wp_nav_menu() arguments.
*
* @return string|null Nav menu output to short-circuit with.
*/
function gutenberg_output_block_nav_menu( $output, $args ) {
// We should uncomment the line below when the block-nav-menus feature becomes stable.
// @see https://github.com/WordPress/gutenberg/issues/34265.
/*if ( ! current_theme_supports( 'block-nav-menus' ) ) {*/
if ( true ) {
return null;
}
// BEGIN: Code that already exists in wp_nav_menu().
// Get the nav menu based on the requested menu.
$menu = wp_get_nav_menu_object( $args->menu );
// Get the nav menu based on the theme_location.
$locations = get_nav_menu_locations();
if ( ! $menu && $args->theme_location && $locations && isset( $locations[ $args->theme_location ] ) ) {
$menu = wp_get_nav_menu_object( $locations[ $args->theme_location ] );
}
// Get the first menu that has items if we still can't find a menu.
if ( ! $menu && ! $args->theme_location ) {
$menus = wp_get_nav_menus();
foreach ( $menus as $menu_maybe ) {
$menu_items = wp_get_nav_menu_items( $menu_maybe->term_id, array( 'update_post_term_cache' => false ) );
if ( $menu_items ) {
$menu = $menu_maybe;
break;
}
}
}
if ( empty( $args->menu ) ) {
$args->menu = $menu;
}
// If the menu exists, get its items.
if ( $menu && ! is_wp_error( $menu ) && ! isset( $menu_items ) ) {
$menu_items = wp_get_nav_menu_items( $menu->term_id, array( 'update_post_term_cache' => false ) );
}
// Set up the $menu_item variables.
_wp_menu_item_classes_by_context( $menu_items );
$sorted_menu_items = array();
foreach ( (array) $menu_items as $menu_item ) {
$sorted_menu_items[ $menu_item->menu_order ] = $menu_item;
}
unset( $menu_items, $menu_item );
// END: Code that already exists in wp_nav_menu().
$menu_items_by_parent_id = array();
foreach ( $sorted_menu_items as $menu_item ) {
$menu_items_by_parent_id[ $menu_item->menu_item_parent ][] = $menu_item;
}
$block_attributes = array();
if ( isset( $args->block_attributes ) ) {
$block_attributes = $args->block_attributes;
}
$navigation_block = array(
'blockName' => 'core/navigation',
'attrs' => $block_attributes,
'innerBlocks' => gutenberg_convert_menu_items_to_blocks(
isset( $menu_items_by_parent_id[0] )
? $menu_items_by_parent_id[0]
: array(),
$menu_items_by_parent_id
),
);
return render_block( $navigation_block );
}
add_filter( 'pre_wp_nav_menu', 'gutenberg_output_block_nav_menu', 10, 2 );
/**
* Shim that makes nav-menus.php nicely display a menu item with its `type` set to
* `'block'`.
*
* Specifically, this shim makes it so that `Walker_Nav_Menu_Edit::start_el()`
* outputs extra form fields. When merged to Core, this markup should exist in
* `Walker_Nav_Menu_Edit::start_el()`.
*
* This shim can be removed when the Gutenberg plugin requires a WordPress
* version that has the ticket below.
*
* @see https://core.trac.wordpress.org/ticket/50544
*
* @param int $item_id Menu item ID.
* @param WP_Post $item Menu item data object.
*/
function gutenberg_output_block_menu_item_custom_fields( $item_id, $item ) {
if ( 'block' === $item->type ) {
?>
<p class="field-content description description-wide">
<label for="edit-menu-item-content-<?php echo $item_id; ?>">
<?php _e( 'Content', 'gutenberg' ); ?><br />
<textarea id="edit-menu-item-content-<?php echo $item_id; ?>" class="widefat" rows="3" cols="20" name="menu-item-content[<?php echo $item_id; ?>]" readonly><?php echo esc_textarea( trim( $item->content ) ); ?></textarea>
</label>
</p>
<?php
}
}
add_action( 'wp_nav_menu_item_custom_fields', 'gutenberg_output_block_menu_item_custom_fields', 10, 2 );
/**
* Shim that adds extra styling to nav-menus.php. This lets us style menu items
* that have a `type` set to `'block'`. When merged to Core, this CSS should be
* moved to nav-menus.css.
*
* This shim can be removed when the Gutenberg plugin requires a WordPress
* version that has the ticket below.
*
* @see https://core.trac.wordpress.org/ticket/50544
*
* @param string $hook The current admin page.
*/
function gutenberg_add_block_menu_item_styles_to_nav_menus( $hook ) {
if ( 'nav-menus.php' === $hook ) {
$css = <<<CSS
/**
* HACK: We're hiding the description field using CSS because this
* cannot be done using a filter. When merged to Core, we should
* actually remove the field from
* `Walker_Nav_Menu_Edit::start_el()`.
*/
.menu-item-block .description:not(.field-content) {
display: none;
}
CSS;
wp_add_inline_style( 'nav-menus', $css );
}
}
add_action( 'admin_enqueue_scripts', 'gutenberg_add_block_menu_item_styles_to_nav_menus' );