* Block template loader functions.
* Adds necessary hooks to resolve '_wp-find-template' requests.
function _add_template_loader_filters() {
if ( isset( $_GET['_wp-find-template'] ) && current_theme_supports( 'block-templates' ) ) {
add_action( 'pre_get_posts', '_resolve_template_for_new_post' );
* Renders a warning screen for empty block templates.
* @param WP_Block_Template $block_template The block template object.
* @return string The warning screen HTML.
function wp_render_empty_block_template_warning( $block_template ) {
wp_enqueue_style( 'wp-empty-template-alert' );
/* translators: %1$s: Block template title. %2$s: Empty template warning message. %3$s: Edit template link. %4$s: Edit template button label. */
'<div id="wp-empty-template-alert">
<a href="%3$s" class="wp-element-button">
esc_html( $block_template->title ),
__( 'This page is blank because the template is empty. You can reset or customize it in the Site Editor.' ),
get_edit_post_link( $block_template->wp_id, 'site-editor' ),
* Finds a block template with equal or higher specificity than a given PHP template file.
* Internally, this communicates the block content that needs to be used by the template canvas through a global variable.
* @since 6.3.0 Added `$_wp_current_template_id` global for editing of current template directly from the admin bar.
* @global string $_wp_current_template_content
* @global string $_wp_current_template_id
* @param string $template Path to the template. See locate_template().
* @param string $type Sanitized filename without extension.
* @param string[] $templates A list of template candidates, in descending order of priority.
* @return string The path to the Site Editor template canvas file, or the fallback PHP template.
function locate_block_template( $template, $type, array $templates ) {
global $_wp_current_template_content, $_wp_current_template_id;
if ( ! current_theme_supports( 'block-templates' ) ) {
* locate_template() has found a PHP template at the path specified by $template.
* That means that we have a fallback candidate if we cannot find a block template
* with higher specificity.
* Thus, before looking for matching block themes, we shorten our list of candidate
// Locate the index of $template (without the theme directory path) in $templates.
$relative_template_path = str_replace(
array( get_stylesheet_directory() . '/', get_template_directory() . '/' ),
$index = array_search( $relative_template_path, $templates, true );
// If the template hierarchy algorithm has successfully located a PHP template file,
// we will only consider block templates with higher or equal specificity.
$templates = array_slice( $templates, 0, $index + 1 );
$block_template = resolve_block_template( $type, $templates, $template );
$_wp_current_template_id = $block_template->id;
if ( empty( $block_template->content ) ) {
if ( is_user_logged_in() ) {
$_wp_current_template_content = wp_render_empty_block_template_warning( $block_template );
if ( $block_template->has_theme_file ) {
// Show contents from theme template if user is not logged in.
$theme_template = _get_block_template_file( 'wp_template', $block_template->slug );
$_wp_current_template_content = file_get_contents( $theme_template['path'] );
$_wp_current_template_content = $block_template->content;
} elseif ( ! empty( $block_template->content ) ) {
$_wp_current_template_content = $block_template->content;
if ( isset( $_GET['_wp-find-template'] ) ) {
wp_send_json_success( $block_template );
if ( 'index' === $type ) {
if ( isset( $_GET['_wp-find-template'] ) ) {
wp_send_json_error( array( 'message' => __( 'No matching template found.' ) ) );
return ''; // So that the template loader keeps looking for templates.
// Add hooks for template canvas.
// Add viewport meta tag.
add_action( 'wp_head', '_block_template_viewport_meta_tag', 0 );
// Render title tag with content, regardless of whether theme has title-tag support.
remove_action( 'wp_head', '_wp_render_title_tag', 1 ); // Remove conditional title tag rendering...
add_action( 'wp_head', '_block_template_render_title_tag', 1 ); // ...and make it unconditional.
// This file will be included instead of the theme's template file.
return ABSPATH . WPINC . '/template-canvas.php';
* Returns the correct 'wp_template' to render for the request template type.
* @since 5.9.0 Added the `$fallback_template` parameter.
* @param string $template_type The current template type.
* @param string[] $template_hierarchy The current template hierarchy, ordered by priority.
* @param string $fallback_template A PHP fallback template to use if no matching block template is found.
* @return WP_Block_Template|null template A template object, or null if none could be found.
function resolve_block_template( $template_type, $template_hierarchy, $fallback_template ) {
if ( ! $template_type ) {
if ( empty( $template_hierarchy ) ) {
$template_hierarchy = array( $template_type );
'_strip_template_file_suffix',
// Find all potential templates 'wp_template' post matching the hierarchy.
$templates = get_block_templates( $query );
// Order these templates per slug priority.
// Build map of template slugs to their priority in the current hierarchy.
$slug_priorities = array_flip( $slugs );
static function ( $template_a, $template_b ) use ( $slug_priorities ) {
return $slug_priorities[ $template_a->slug ] - $slug_priorities[ $template_b->slug ];
$theme_base_path = get_stylesheet_directory() . DIRECTORY_SEPARATOR;
$parent_theme_base_path = get_template_directory() . DIRECTORY_SEPARATOR;
// Is the active theme a child theme, and is the PHP fallback template part of it?
str_starts_with( $fallback_template, $theme_base_path ) &&
! str_contains( $fallback_template, $parent_theme_base_path )
$fallback_template_slug = substr(
// Starting position of slug.
strpos( $fallback_template, $theme_base_path ) + strlen( $theme_base_path ),
// Is our candidate block template's slug identical to our PHP fallback template's?
$fallback_template_slug === $templates[0]->slug &&
'theme' === $templates[0]->source
// Unfortunately, we cannot trust $templates[0]->theme, since it will always
// be set to the active theme's slug by _build_block_template_result_from_file(),
// even if the block template is really coming from the active theme's parent.
// (The reason for this is that we want it to be associated with the active theme
// -- not its parent -- once we edit it and store it to the DB as a wp_template CPT.)
// Instead, we use _get_block_template_file() to locate the block template file.
$template_file = _get_block_template_file( 'wp_template', $fallback_template_slug );
if ( $template_file && get_template() === $template_file['theme'] ) {
// The block template is part of the parent theme, so we
// have to give precedence to the child theme's PHP template.
array_shift( $templates );
return count( $templates ) ? $templates[0] : null;
* Displays title tag with content, regardless of whether theme has title-tag support.
* @see _wp_render_title_tag()
function _block_template_render_title_tag() {
echo '<title>' . wp_get_document_title() . '</title>' . "\n";
* Returns the markup for the current template.
* @global string $_wp_current_template_id
* @global string $_wp_current_template_content
* @global WP_Embed $wp_embed WordPress Embed object.
* @global WP_Query $wp_query WordPress Query object.
* @return string Block template markup.
function get_the_block_template_html() {
global $_wp_current_template_id, $_wp_current_template_content, $wp_embed, $wp_query;
if ( ! $_wp_current_template_content ) {
if ( is_user_logged_in() ) {
return '<h1>' . esc_html__( 'No matching template found' ) . '</h1>';
$content = $wp_embed->run_shortcode( $_wp_current_template_content );
$content = $wp_embed->autoembed( $content );
$content = shortcode_unautop( $content );
$content = do_shortcode( $content );
* Most block themes omit the `core/query` and `core/post-template` blocks in their singular content templates.
* While this technically still works since singular content templates are always for only one post, it results in
* the main query loop never being entered which causes bugs in core and the plugin ecosystem.
* The workaround below ensures that the loop is started even for those singular templates. The while loop will by
* definition only go through a single iteration, i.e. `do_blocks()` is only called once. Additional safeguard
* checks are included to ensure the main query loop has not been tampered with and really only encompasses a
* Even if the block template contained a `core/query` and `core/post-template` block referencing the main query
* loop, it would not cause errors since it would use a cloned instance and go through the same loop of a single
* post, within the actual main query loop.
* This special logic should be skipped if the current template does not come from the current theme, in which case
* it has been injected by a plugin by hijacking the block template loader mechanism. In that case, entirely custom
* logic may be applied which is unpredictable and therefore safer to omit this special handling on.
$_wp_current_template_id &&
str_starts_with( $_wp_current_template_id, get_stylesheet() . '//' ) &&
1 === $wp_query->post_count &&
$content = do_blocks( $content );
$content = do_blocks( $content );
$content = wptexturize( $content );
$content = convert_smilies( $content );
$content = wp_filter_content_tags( $content, 'template' );
$content = str_replace( ']]>', ']]>', $content );
// Wrap block template in .wp-site-blocks to allow for specific descendant styles
// (e.g. `.wp-site-blocks > *`).
return '<div class="wp-site-blocks">' . $content . '</div>';
* Renders a 'viewport' meta tag.
* This is hooked into {@see 'wp_head'} to decouple its output from the default template canvas.
function _block_template_viewport_meta_tag() {
echo '<meta name="viewport" content="width=device-width, initial-scale=1" />' . "\n";
* Strips .php or .html suffix from template file names.
* @param string $template_file Template file name.
* @return string Template file name without extension.
function _strip_template_file_suffix( $template_file ) {
return preg_replace( '/\.(php|html)$/', '', $template_file );
* Removes post details from block context when rendering a block template.
* @param array $context Default context.
* @return array Filtered context.
function _block_template_render_without_post_block_context( $context ) {
* When loading a template directly and not through a page that resolves it,
* the top-level post ID and type context get set to that of the template.
* Templates are just the structure of a site, and they should not be available
* as post context because blocks like Post Content would recurse infinitely.
if ( isset( $context['postType'] ) && 'wp_template' === $context['postType'] ) {
unset( $context['postId'] );
unset( $context['postType'] );
* Sets the current WP_Query to return auto-draft posts.
* The auto-draft status indicates a new post, so allow the the WP_Query instance to
* return an auto-draft post for template resolution when editing a new post.
* @param WP_Query $wp_query Current WP_Query instance, passed by reference.
function _resolve_template_for_new_post( $wp_query ) {
if ( ! $wp_query->is_main_query() ) {
remove_filter( 'pre_get_posts', '_resolve_template_for_new_post' );
$page_id = isset( $wp_query->query['page_id'] ) ? $wp_query->query['page_id'] : null;
// Posts, including custom post types.
$p = isset( $wp_query->query['p'] ) ? $wp_query->query['p'] : null;
$post_id = $page_id ? $page_id : $p;
$post = get_post( $post_id );
'auto-draft' === $post->post_status &&
current_user_can( 'edit_post', $post->ID )
$wp_query->set( 'post_status', 'auto-draft' );
* Register a block template.
* @param string $template_name Template name in the form of `plugin_uri//template_name`.
* @param array|string $args {
* @type string $title Optional. Title of the template as it will be shown in the Site Editor
* @type string $description Optional. Description of the template as it will be shown in the Site
* @type string $content Optional. Default content of the template that will be used when the
* template is rendered or edited in the editor.
* @type string[] $post_types Optional. Array of post types to which the template should be available.
* @type string $plugin Optional. Slug of the plugin that registers the template.
* @return WP_Block_Template|WP_Error The registered template object on success, WP_Error object on failure.
function register_block_template( $template_name, $args = array() ) {
return WP_Block_Templates_Registry::get_instance()->register( $template_name, $args );
* Unregister a block template.
* @param string $template_name Template name in the form of `plugin_uri//template_name`.
* @return WP_Block_Template|WP_Error The unregistered template object on success, WP_Error object on failure or if the
* template doesn't exist.
function unregister_block_template( $template_name ) {
return WP_Block_Templates_Registry::get_instance()->unregister( $template_name );
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
