<?php
/**
* Template loading functions.
*
* @package WordPress
* @subpackage Template
*/
/**
* Retrieves path to a template.
*
* Used to quickly retrieve the path of a template without including the file
* extension. It will also check the parent theme, if the file exists, with
* the use of locate_template(). Allows for more generic template location
* without the use of the other get_*_template() functions.
*
* @since 1.5.0
*
* @param string $type Filename without extension.
* @param string[] $templates An optional list of template candidates.
* @return string Full path to template file.
*/
function get_query_template( $type, $templates = array() ) {
$type = preg_replace( '|[^a-z0-9-]+|', '', $type );
if ( empty( $templates ) ) {
$templates = array( "{$type}.php" );
}
/**
* Filters the list of template filenames that are searched for when retrieving a template to use.
*
* The dynamic portion of the hook name, `$type`, refers to the filename -- minus the file
* extension and any non-alphanumeric characters delimiting words -- of the file to load.
* The last element in the array should always be the fallback template for this query type.
*
* Possible hook names include:
*
* - `404_template_hierarchy`
* - `archive_template_hierarchy`
* - `attachment_template_hierarchy`
* - `author_template_hierarchy`
* - `category_template_hierarchy`
* - `date_template_hierarchy`
* - `embed_template_hierarchy`
* - `frontpage_template_hierarchy`
* - `home_template_hierarchy`
* - `index_template_hierarchy`
* - `page_template_hierarchy`
* - `paged_template_hierarchy`
* - `privacypolicy_template_hierarchy`
* - `search_template_hierarchy`
* - `single_template_hierarchy`
* - `singular_template_hierarchy`
* - `tag_template_hierarchy`
* - `taxonomy_template_hierarchy`
*
* @since 4.7.0
*
* @param string[] $templates A list of template candidates, in descending order of priority.
*/
$templates = apply_filters( "{$type}_template_hierarchy", $templates );
$template = locate_template( $templates );
$template = locate_block_template( $template, $type, $templates );
/**
* Filters the path of the queried template by type.
*
* The dynamic portion of the hook name, `$type`, refers to the filename -- minus the file
* extension and any non-alphanumeric characters delimiting words -- of the file to load.
* This hook also applies to various types of files loaded as part of the Template Hierarchy.
*
* Possible hook names include:
*
* - `404_template`
* - `archive_template`
* - `attachment_template`
* - `author_template`
* - `category_template`
* - `date_template`
* - `embed_template`
* - `frontpage_template`
* - `home_template`
* - `index_template`
* - `page_template`
* - `paged_template`
* - `privacypolicy_template`
* - `search_template`
* - `single_template`
* - `singular_template`
* - `tag_template`
* - `taxonomy_template`
*
* @since 1.5.0
* @since 4.8.0 The `$type` and `$templates` parameters were added.
*
* @param string $template Path to the template. See locate_template().
* @param string $type Sanitized filename without extension.
* @param string[] $templates A list of template candidates, in descending order of priority.
*/
return apply_filters( "{$type}_template", $template, $type, $templates );
}
/**
* Retrieves path of index template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'index'.
*
* @since 3.0.0
*
* @see get_query_template()
*
* @return string Full path to index template file.
*/
function get_index_template() {
return get_query_template( 'index' );
}
/**
* Retrieves path of 404 template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is '404'.
*
* @since 1.5.0
*
* @see get_query_template()
*
* @return string Full path to 404 template file.
*/
function get_404_template() {
return get_query_template( '404' );
}
/**
* Retrieves path of archive template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'archive'.
*
* @since 1.5.0
*
* @see get_query_template()
*
* @return string Full path to archive template file.
*/
function get_archive_template() {
$post_types = array_filter( (array) get_query_var( 'post_type' ) );
$templates = array();
if ( count( $post_types ) === 1 ) {
$post_type = reset( $post_types );
$templates[] = "archive-{$post_type}.php";
}
$templates[] = 'archive.php';
return get_query_template( 'archive', $templates );
}
/**
* Retrieves path of post type archive template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'archive'.
*
* @since 3.7.0
*
* @see get_archive_template()
*
* @return string Full path to archive template file.
*/
function get_post_type_archive_template() {
$post_type = get_query_var( 'post_type' );
if ( is_array( $post_type ) ) {
$post_type = reset( $post_type );
}
$obj = get_post_type_object( $post_type );
if ( ! ( $obj instanceof WP_Post_Type ) || ! $obj->has_archive ) {
return '';
}
return get_archive_template();
}
/**
* Retrieves path of author template in current or parent template.
*
* The hierarchy for this template looks like:
*
* 1. author-{nicename}.php
* 2. author-{id}.php
* 3. author.php
*
* An example of this is:
*
* 1. author-john.php
* 2. author-1.php
* 3. author.php
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'author'.
*
* @since 1.5.0
*
* @see get_query_template()
*
* @return string Full path to author template file.
*/
function get_author_template() {
$author = get_queried_object();
$templates = array();
if ( $author instanceof WP_User ) {
$templates[] = "author-{$author->user_nicename}.php";
$templates[] = "author-{$author->ID}.php";
}
$templates[] = 'author.php';
return get_query_template( 'author', $templates );
}
/**
* Retrieves path of category template in current or parent template.
*
* The hierarchy for this template looks like:
*
* 1. category-{slug}.php
* 2. category-{id}.php
* 3. category.php
*
* An example of this is:
*
* 1. category-news.php
* 2. category-2.php
* 3. category.php
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'category'.
*
* @since 1.5.0
* @since 4.7.0 The decoded form of `category-{slug}.php` was added to the top of the
* template hierarchy when the category slug contains multibyte characters.
*
* @see get_query_template()
*
* @return string Full path to category template file.
*/
function get_category_template() {
$category = get_queried_object();
$templates = array();
if ( ! empty( $category->slug ) ) {
$slug_decoded = urldecode( $category->slug );
if ( $slug_decoded !== $category->slug ) {
$templates[] = "category-{$slug_decoded}.php";
}
$templates[] = "category-{$category->slug}.php";
$templates[] = "category-{$category->term_id}.php";
}
$templates[] = 'category.php';
return get_query_template( 'category', $templates );
}
/**
* Retrieves path of tag template in current or parent template.
*
* The hierarchy for this template looks like:
*
* 1. tag-{slug}.php
* 2. tag-{id}.php
* 3. tag.php
*
* An example of this is:
*
* 1. tag-wordpress.php
* 2. tag-3.php
* 3. tag.php
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'tag'.
*
* @since 2.3.0
* @since 4.7.0 The decoded form of `tag-{slug}.php` was added to the top of the
* template hierarchy when the tag slug contains multibyte characters.
*
* @see get_query_template()
*
* @return string Full path to tag template file.
*/
function get_tag_template() {
$tag = get_queried_object();
$templates = array();
if ( ! empty( $tag->slug ) ) {
$slug_decoded = urldecode( $tag->slug );
if ( $slug_decoded !== $tag->slug ) {
$templates[] = "tag-{$slug_decoded}.php";
}
$templates[] = "tag-{$tag->slug}.php";
$templates[] = "tag-{$tag->term_id}.php";
}
$templates[] = 'tag.php';
return get_query_template( 'tag', $templates );
}
/**
* Retrieves path of custom taxonomy term template in current or parent template.
*
* The hierarchy for this template looks like:
*
* 1. taxonomy-{taxonomy_slug}-{term_slug}.php
* 2. taxonomy-{taxonomy_slug}-{term_id}.php
* 3. taxonomy-{taxonomy_slug}.php
* 4. taxonomy.php
*
* An example of this is:
*
* 1. taxonomy-location-texas.php
* 2. taxonomy-location-67.php
* 3. taxonomy-location.php
* 4. taxonomy.php
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'taxonomy'.
*
* @since 2.5.0
* @since 4.7.0 The decoded form of `taxonomy-{taxonomy_slug}-{term_slug}.php` was added to the top of the
* template hierarchy when the term slug contains multibyte characters.
* @since 6.9.0 Added `taxonomy-{taxonomy_slug}-{term_id}.php` to the hierarchy.
*
* @see get_query_template()
*
* @return string Full path to custom taxonomy term template file.
*/
function get_taxonomy_template() {
$term = get_queried_object();
$templates = array();
if ( ! empty( $term->slug ) ) {
$taxonomy = $term->taxonomy;
$slug_decoded = urldecode( $term->slug );
if ( $slug_decoded !== $term->slug ) {
$templates[] = "taxonomy-$taxonomy-{$slug_decoded}.php";
}
$templates[] = "taxonomy-$taxonomy-{$term->slug}.php";
$templates[] = "taxonomy-$taxonomy-{$term->term_id}.php";
$templates[] = "taxonomy-$taxonomy.php";
}
$templates[] = 'taxonomy.php';
return get_query_template( 'taxonomy', $templates );
}
/**
* Retrieves path of date template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'date'.
*
* @since 1.5.0
*
* @see get_query_template()
*
* @return string Full path to date template file.
*/
function get_date_template() {
return get_query_template( 'date' );
}
/**
* Retrieves path of home template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'home'.
*
* @since 1.5.0
*
* @see get_query_template()
*
* @return string Full path to home template file.
*/
function get_home_template() {
$templates = array( 'home.php', 'index.php' );
return get_query_template( 'home', $templates );
}
/**
* Retrieves path of front page template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'frontpage'.
*
* @since 3.0.0
*
* @see get_query_template()
*
* @return string Full path to front page template file.
*/
function get_front_page_template() {
$templates = array( 'front-page.php' );
return get_query_template( 'frontpage', $templates );
}
/**
* Retrieves path of Privacy Policy page template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'privacypolicy'.
*
* @since 5.2.0
*
* @see get_query_template()
*
* @return string Full path to privacy policy template file.
*/
function get_privacy_policy_template() {
$templates = array( 'privacy-policy.php' );
return get_query_template( 'privacypolicy', $templates );
}
/**
* Retrieves path of page template in current or parent template.
*
* Note: For block themes, use locate_block_template() function instead.
*
* The hierarchy for this template looks like:
*
* 1. {Page Template}.php
* 2. page-{page_name}.php
* 3. page-{id}.php
* 4. page.php
*
* An example of this is:
*
* 1. page-templates/full-width.php
* 2. page-about.php
* 3. page-4.php
* 4. page.php
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'page'.
*
* @since 1.5.0
* @since 4.7.0 The decoded form of `page-{page_name}.php` was added to the top of the
* template hierarchy when the page name contains multibyte characters.
*
* @see get_query_template()
*
* @return string Full path to page template file.
*/
function get_page_template() {
$id = get_queried_object_id();
$template = get_page_template_slug();
$pagename = get_query_var( 'pagename' );
if ( ! $pagename && $id ) {
/*
* If a static page is set as the front page, $pagename will not be set.
* Retrieve it from the queried object.
*/
$post = get_queried_object();
if ( $post ) {
$pagename = $post->post_name;
}
}
$templates = array();
if ( $template && 0 === validate_file( $template ) ) {
$templates[] = $template;
}
if ( $pagename ) {
$pagename_decoded = urldecode( $pagename );
if ( $pagename_decoded !== $pagename ) {
$templates[] = "page-{$pagename_decoded}.php";
}
$templates[] = "page-{$pagename}.php";
}
if ( $id ) {
$templates[] = "page-{$id}.php";
}
$templates[] = 'page.php';
return get_query_template( 'page', $templates );
}
/**
* Retrieves path of search template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'search'.
*
* @since 1.5.0
*
* @see get_query_template()
*
* @return string Full path to search template file.
*/
function get_search_template() {
return get_query_template( 'search' );
}
/**
* Retrieves path of single template in current or parent template. Applies to single Posts,
* single Attachments, and single custom post types.
*
* The hierarchy for this template looks like:
*
* 1. {Post Type Template}.php
* 2. single-{post_type}-{post_name}.php
* 3. single-{post_type}.php
* 4. single.php
*
* An example of this is:
*
* 1. templates/full-width.php
* 2. single-post-hello-world.php
* 3. single-post.php
* 4. single.php
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'single'.
*
* @since 1.5.0
* @since 4.4.0 `single-{post_type}-{post_name}.php` was added to the top of the template hierarchy.
* @since 4.7.0 The decoded form of `single-{post_type}-{post_name}.php` was added to the top of the
* template hierarchy when the post name contains multibyte characters.
* @since 4.7.0 `{Post Type Template}.php` was added to the top of the template hierarchy.
*
* @see get_query_template()
*
* @return string Full path to single template file.
*/
function get_single_template() {
$object = get_queried_object();
$templates = array();
if ( ! empty( $object->post_type ) ) {
$template = get_page_template_slug( $object );
if ( $template && 0 === validate_file( $template ) ) {
$templates[] = $template;
}
$name_decoded = urldecode( $object->post_name );
if ( $name_decoded !== $object->post_name ) {
$templates[] = "single-{$object->post_type}-{$name_decoded}.php";
}
$templates[] = "single-{$object->post_type}-{$object->post_name}.php";
$templates[] = "single-{$object->post_type}.php";
}
$templates[] = 'single.php';
return get_query_template( 'single', $templates );
}
/**
* Retrieves an embed template path in the current or parent template.
*
* The hierarchy for this template looks like:
*
* 1. embed-{post_type}-{post_format}.php
* 2. embed-{post_type}.php
* 3. embed.php
*
* An example of this is:
*
* 1. embed-post-audio.php
* 2. embed-post.php
* 3. embed.php
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'embed'.
*
* @since 4.5.0
*
* @see get_query_template()
*
* @return string Full path to embed template file.
*/
function get_embed_template() {
$object = get_queried_object();
$templates = array();
if ( ! empty( $object->post_type ) ) {
$post_format = get_post_format( $object );
if ( $post_format ) {
$templates[] = "embed-{$object->post_type}-{$post_format}.php";
}
$templates[] = "embed-{$object->post_type}.php";
}
$templates[] = 'embed.php';
return get_query_template( 'embed', $templates );
}
/**
* Retrieves the path of the singular template in current or parent template.
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'singular'.
*
* @since 4.3.0
*
* @see get_query_template()
*
* @return string Full path to singular template file.
*/
function get_singular_template() {
return get_query_template( 'singular' );
}
/**
* Retrieves path of attachment template in current or parent template.
*
* The hierarchy for this template looks like:
*
* 1. {mime_type}-{sub_type}.php
* 2. {sub_type}.php
* 3. {mime_type}.php
* 4. attachment.php
*
* An example of this is:
*
* 1. image-jpeg.php
* 2. jpeg.php
* 3. image.php
* 4. attachment.php
*
* The template hierarchy and template path are filterable via the {@see '$type_template_hierarchy'}
* and {@see '$type_template'} dynamic hooks, where `$type` is 'attachment'.
*
* @since 2.0.0
* @since 4.3.0 The order of the mime type logic was reversed so the hierarchy is more logical.
*
* @see get_query_template()
*
* @return string Full path to attachment template file.
*/
function get_attachment_template() {
$attachment = get_queried_object();
$templates = array();
if ( $attachment ) {
if ( str_contains( $attachment->post_mime_type, '/' ) ) {
list( $type, $subtype ) = explode( '/', $attachment->post_mime_type );
} else {
list( $type, $subtype ) = array( $attachment->post_mime_type, '' );
}
if ( ! empty( $subtype ) ) {
$templates[] = "{$type}-{$subtype}.php";
$templates[] = "{$subtype}.php";
}
$templates[] = "{$type}.php";
}
$templates[] = 'attachment.php';
return get_query_template( 'attachment', $templates );
}
/**
* Set up the globals used for template loading.
*
* @since 6.5.0
*
* @global string $wp_stylesheet_path Path to current theme's stylesheet directory.
* @global string $wp_template_path Path to current theme's template directory.
*/
function wp_set_template_globals() {
global $wp_stylesheet_path, $wp_template_path;
$wp_stylesheet_path = get_stylesheet_directory();
$wp_template_path = get_template_directory();
}
/**
* Retrieves the name of the highest priority template file that exists.
*
* Searches in the stylesheet directory before the template directory and
* wp-includes/theme-compat so that themes which inherit from a parent theme
* can just overload one file.
*
* @since 2.7.0
* @since 5.5.0 The `$args` parameter was added.
*
* @global string $wp_stylesheet_path Path to current theme's stylesheet directory.
* @global string $wp_template_path Path to current theme's template directory.
*
* @param string|array $template_names Template file(s) to search for, in order.
* @param bool $load If true the template file will be loaded if it is found.
* @param bool $load_once Whether to require_once or require. Has no effect if `$load` is false.
* Default true.
* @param array $args Optional. Additional arguments passed to the template.
* Default empty array.
* @return string The template filename if one is located.
*/
function locate_template( $template_names, $load = false, $load_once = true, $args = array() ) {
global $wp_stylesheet_path, $wp_template_path;
if ( ! isset( $wp_stylesheet_path ) || ! isset( $wp_template_path ) ) {
wp_set_template_globals();
}
$is_child_theme = is_child_theme();
$located = '';
foreach ( (array) $template_names as $template_name ) {
if ( ! $template_name ) {
continue;
}
if ( file_exists( $wp_stylesheet_path . '/' . $template_name ) ) {
$located = $wp_stylesheet_path . '/' . $template_name;
break;
} elseif ( $is_child_theme && file_exists( $wp_template_path . '/' . $template_name ) ) {
$located = $wp_template_path . '/' . $template_name;
break;
} elseif ( file_exists( ABSPATH . WPINC . '/theme-compat/' . $template_name ) ) {
$located = ABSPATH . WPINC . '/theme-compat/' . $template_name;
break;
}
}
if ( $load && '' !== $located ) {
load_template( $located, $load_once, $args );
}
return $located;
}
/**
* Requires the template file with WordPress environment.
*
* The globals are set up for the template file to ensure that the WordPress
* environment is available from within the function. The query variables are
* also available.
*
* @since 1.5.0
* @since 5.5.0 The `$args` parameter was added.
*
* @global array $posts
* @global WP_Post $post Global post object.
* @global bool $wp_did_header
* @global WP_Query $wp_query WordPress Query object.
* @global WP_Rewrite $wp_rewrite WordPress rewrite component.
* @global wpdb $wpdb WordPress database abstraction object.
* @global string $wp_version
* @global WP $wp Current WordPress environment instance.
* @global int $id
* @global WP_Comment $comment Global comment object.
* @global int $user_ID
*
* @param string $_template_file Path to template file.
* @param bool $load_once Whether to require_once or require. Default true.
* @param array $args Optional. Additional arguments passed to the template.
* Default empty array.
*/
function load_template( $_template_file, $load_once = true, $args = array() ) {
global $posts, $post, $wp_did_header, $wp_query, $wp_rewrite, $wpdb, $wp_version, $wp, $id, $comment, $user_ID;
if ( is_array( $wp_query->query_vars ) ) {
/*
* This use of extract() cannot be removed. There are many possible ways that
* templates could depend on variables that it creates existing, and no way to
* detect and deprecate it.
*
* Passing the EXTR_SKIP flag is the safest option, ensuring globals and
* function variables cannot be overwritten.
*/
// phpcs:ignore WordPress.PHP.DontExtract.extract_extract
extract( $wp_query->query_vars, EXTR_SKIP );
}
if ( isset( $s ) ) {
$s = esc_attr( $s );
}
/**
* Fires before a template file is loaded.
*
* @since 6.1.0
*
* @param string $_template_file The full path to the template file.
* @param bool $load_once Whether to require_once or require.
* @param array $args Additional arguments passed to the template.
*/
do_action( 'wp_before_load_template', $_template_file, $load_once, $args );
if ( $load_once ) {
require_once $_template_file;
} else {
require $_template_file;
}
/**
* Fires after a template file is loaded.
*
* @since 6.1.0
*
* @param string $_template_file The full path to the template file.
* @param bool $load_once Whether to require_once or require.
* @param array $args Additional arguments passed to the template.
*/
do_action( 'wp_after_load_template', $_template_file, $load_once, $args );
}
/**
* Checks whether the template should be output buffered for enhancement.
*
* By default, an output buffer is only started if a {@see 'wp_template_enhancement_output_buffer'} filter has been
* added by the time a template is included at the {@see 'wp_before_include_template'} action. This allows template
* responses to be streamed as much as possible when no template enhancements are registered to apply.
*
* @since 6.9.0
*
* @return bool Whether the template should be output-buffered for enhancement.
*/
function wp_should_output_buffer_template_for_enhancement(): bool {
/**
* Filters whether the template should be output-buffered for enhancement.
*
* By default, an output buffer is only started if a {@see 'wp_template_enhancement_output_buffer'} filter has been
* added or if a plugin has added a {@see 'wp_finalized_template_enhancement_output_buffer'} action. For this
* default to apply, either of the hooks must be added by the time the template is included at the
* {@see 'wp_before_include_template'} action. This allows template responses to be streamed unless the there is
* code which depends on an output buffer being opened. This filter allows a site to opt in to adding such template
* enhancement filters later during the rendering of the template.
*
* @since 6.9.0
*
* @param bool $use_output_buffer Whether an output buffer is started.
*/
return (bool) apply_filters( 'wp_should_output_buffer_template_for_enhancement', has_filter( 'wp_template_enhancement_output_buffer' ) || has_action( 'wp_finalized_template_enhancement_output_buffer' ) );
}
/**
* Starts the template enhancement output buffer.
*
* This function is called immediately before the template is included.
*
* @since 6.9.0
*
* @return bool Whether the output buffer successfully started.
*/
function wp_start_template_enhancement_output_buffer(): bool {
if ( ! wp_should_output_buffer_template_for_enhancement() ) {
return false;
}
$started = ob_start(
'wp_finalize_template_enhancement_output_buffer',
0, // Unlimited buffer size so that entire output is passed to the filter.
/*
* Instead of the default PHP_OUTPUT_HANDLER_STDFLAGS (cleanable, flushable, and removable) being used for
* flags, the PHP_OUTPUT_HANDLER_FLUSHABLE flag must be omitted. If the buffer were flushable, then each time
* that ob_flush() is called, a fragment of the output would be sent into the output buffer callback. This
* output buffer is intended to capture the entire response for processing, as indicated by the chunk size of 0.
* So the buffer does not allow flushing to ensure the entire buffer can be processed, such as for optimizing an
* entire HTML document, where markup in the HEAD may need to be adjusted based on markup that appears late in
* the BODY.
*
* If this ends up being problematic, then PHP_OUTPUT_HANDLER_FLUSHABLE could be added to the $flags and the
* output buffer callback could check if the phase is PHP_OUTPUT_HANDLER_FLUSH and abort any subsequent
* processing while also emitting a _doing_it_wrong().
*
* The output buffer needs to be removable because WordPress calls wp_ob_end_flush_all() and then calls
* wp_cache_close(). If the buffers are not all flushed before wp_cache_close() is closed, then some output buffer
* handlers (e.g. for caching plugins) may fail to be able to store the page output in the object cache.
* See <https://github.com/WordPress/performance/pull/1317#issuecomment-2271955356>.
*/
PHP_OUTPUT_HANDLER_STDFLAGS ^ PHP_OUTPUT_HANDLER_FLUSHABLE
);
if ( $started ) {
/**
* Fires when the template enhancement output buffer has started.
*
* @since 6.9.0
*/
do_action( 'wp_template_enhancement_output_buffer_started' );
}
return $started;
}
/**
* Finalizes the template enhancement output buffer.
*
* Checks to see if the output buffer is complete and contains HTML. If so, runs the content through
* the `wp_template_enhancement_output_buffer` filter. If not, the original content is returned.
*
* @since 6.9.0
*
* @see wp_start_template_enhancement_output_buffer()
*
* @param string $output Output buffer.
* @param int $phase Phase.
* @return string Finalized output buffer.
*/
function wp_finalize_template_enhancement_output_buffer( string $output, int $phase ): string {
// When the output is being cleaned (e.g. pending template is replaced with error page), do not send it through the filter.
if ( ( $phase & PHP_OUTPUT_HANDLER_CLEAN ) !== 0 ) {
return $output;
}
// Detect if the response is an HTML content type.
$is_html_content_type = null;
$html_content_types = array( 'text/html', 'application/xhtml+xml' );
foreach ( headers_list() as $header ) {
$header_parts = explode( ':', strtolower( $header ), 2 );
if (
count( $header_parts ) === 2 &&
'content-type' === $header_parts[0]
) {
/*
* This is looking for very specific content types, therefore it
* doesn’t need to fully parse the header’s value. Instead, it needs
* only assert that the content type is one of the static HTML types.
*
* Example:
*
* Content-Type: text/html; charset=utf8
* Content-Type: text/html ;charset=latin4
* Content-Type:application/xhtml+xml
*/
$media_type = trim( strtok( $header_parts[1], ';' ), " \t" );
$is_html_content_type = in_array( $media_type, $html_content_types, true );
break; // PHP only sends the first Content-Type header in the list.
}
}
if ( null === $is_html_content_type ) {
$is_html_content_type = in_array( ini_get( 'default_mimetype' ), $html_content_types, true );
}
// If the content type is not HTML, short-circuit since it is not relevant for enhancement.
if ( ! $is_html_content_type ) {
/** This action is documented in wp-includes/template.php */
do_action( 'wp_finalized_template_enhancement_output_buffer', $output );
return $output;
}
$filtered_output = $output;
$did_just_catch = false;
$error_log = array();
set_error_handler(
static function ( int $level, string $message, ?string $file = null, ?int $line = null ) use ( &$error_log, &$did_just_catch ) {
// Switch a user error to an exception so that it can be caught and the buffer can be returned.
if ( E_USER_ERROR === $level ) {
throw new Exception( __( 'User error triggered:' ) . ' ' . $message );
}
// Display a caught exception as an error since it prevents any of the output buffer filters from applying.
if ( $did_just_catch ) { // @phpstan-ignore if.alwaysFalse (The variable is set in the catch block below.)
$level = E_USER_ERROR;
}
// Capture a reported error to be displayed by appending to the processed output buffer if display_errors is enabled.
if ( error_reporting() & $level ) {
$error_log[] = compact( 'level', 'message', 'file', 'line' );
}
return false;
}
);
$original_display_errors = ini_get( 'display_errors' );
if ( $original_display_errors ) {
ini_set( 'display_errors', 0 );
}
try {
/**
* Filters the template enhancement output buffer prior to sending to the client.
*
* This filter only applies the HTML output of an included template. This filter is a progressive enhancement
* intended for applications such as optimizing markup to improve frontend page load performance. Sites must not
* depend on this filter applying since they may opt to stream the responses instead. Callbacks for this filter
* are highly discouraged from using regular expressions to do any kind of replacement on the output. Use the
* HTML API (either `WP_HTML_Tag_Processor` or `WP_HTML_Processor`), or else use {@see DOM\HtmlDocument} as of
* PHP 8.4 which fully supports HTML5.
*
* Do not print any output during this filter. While filters normally don't print anything, this is especially
* important since this applies during an output buffer callback. Prior to PHP 8.5, the output will be silently
* omitted, whereas afterward a deprecation notice will be emitted.
*
* Important: Because this filter is applied inside an output buffer callback (i.e. display handler), any
* callbacks added to the filter must not attempt to start their own output buffers. Otherwise, PHP will raise a
* fatal error: "Cannot use output buffering in output buffering display handlers."
*
* @since 6.9.0
*
* @param string $filtered_output HTML template enhancement output buffer.
* @param string $output Original HTML template output buffer.
*/
$filtered_output = (string) apply_filters( 'wp_template_enhancement_output_buffer', $filtered_output, $output );
} catch ( Throwable $throwable ) {
// Emit to the error log as a warning not as an error to prevent halting execution.
$did_just_catch = true;
trigger_error(
sprintf(
/* translators: %s is the throwable class name */
__( 'Uncaught "%s" thrown:' ),
get_class( $throwable )
) . ' ' . $throwable->getMessage(),
E_USER_WARNING
);
$did_just_catch = false;
}
try {
/**
* Fires after the template enhancement output buffer has been finalized.
*
* This happens immediately before the template enhancement output buffer is flushed. No output may be printed
* at this action; prior to PHP 8.5, the output will be silently omitted, whereas afterward a deprecation notice
* will be emitted. Nevertheless, HTTP headers may be sent, which makes this action complimentary to the
* {@see 'send_headers'} action, in which headers may be sent before the template has started rendering. In
* contrast, this `wp_finalized_template_enhancement_output_buffer` action is the possible point at which HTTP
* headers can be sent. This action does not fire if the "template enhancement output buffer" was not started.
* This output buffer is automatically started if this action is added before
* {@see wp_start_template_enhancement_output_buffer()} runs at the {@see 'wp_before_include_template'} action
* with priority 1000. Before this point, the output buffer will also be started automatically if there was a
* {@see 'wp_template_enhancement_output_buffer'} filter added, or if the
* {@see 'wp_should_output_buffer_template_for_enhancement'} filter is made to return `true`.
*
* Important: Because this action fires inside an output buffer callback (i.e. display handler), any callbacks
* added to the action must not attempt to start their own output buffers. Otherwise, PHP will raise a fatal
* error: "Cannot use output buffering in output buffering display handlers."
*
* @since 6.9.0
*
* @param string $output Finalized output buffer.
*/
do_action( 'wp_finalized_template_enhancement_output_buffer', $filtered_output );
} catch ( Throwable $throwable ) {
// Emit to the error log as a warning not as an error to prevent halting execution.
$did_just_catch = true;
trigger_error(
sprintf(
/* translators: %s is the class name */
__( 'Uncaught "%s" thrown:' ),
get_class( $throwable )
) . ' ' . $throwable->getMessage(),
E_USER_WARNING
);
$did_just_catch = false;
}
// Append any errors to be displayed before returning flushing the buffer.
if ( $original_display_errors && 'stderr' !== $original_display_errors ) {
foreach ( $error_log as $error ) {
switch ( $error['level'] ) {
case E_USER_NOTICE:
$type = 'Notice';
break;
case E_USER_DEPRECATED:
$type = 'Deprecated';
break;
case E_USER_WARNING:
$type = 'Warning';
break;
default:
$type = 'Error';
}
if ( ini_get( 'html_errors' ) ) {
/*
* Adapted from PHP internals: <https://github.com/php/php-src/blob/a979e9f897a90a580e883b1f39ce5673686ffc67/main/main.c#L1478>.
* The self-closing tags are a vestige of the XHTML past!
*/
$format = "%s<br />\n<b>%s</b>: %s in <b>%s</b> on line <b>%s</b><br />\n%s";
} else {
// Adapted from PHP internals: <https://github.com/php/php-src/blob/a979e9f897a90a580e883b1f39ce5673686ffc67/main/main.c#L1492>.
$format = "%s\n%s: %s in %s on line %s\n%s";
}
$filtered_output .= sprintf(
$format,
ini_get( 'error_prepend_string' ),
$type,
$error['message'],
$error['file'],
$error['line'],
ini_get( 'error_append_string' )
);
}
ini_set( 'display_errors', $original_display_errors );
}
restore_error_handler();
return $filtered_output;
}