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Edit File: speculative-loading.php
<?php /** * Speculative loading functions. * * @package WordPress * @subpackage Speculative Loading * @since 6.8.0 */ /** * Returns the speculation rules configuration. * * @since 6.8.0 * @since 7.1.0 The `WP_SPECULATIVE_LOADING_DEFAULT_MODE` and `WP_SPECULATIVE_LOADING_DEFAULT_EAGERNESS` constants and * environment variables can now specify the default mode and eagerness, respectively. * * @see wp_get_speculation_rules_default_configuration() * * @return array<string, string>|null Associative array with 'mode' and 'eagerness' keys, or null if speculative * loading is disabled. * @phpstan-return array{ * mode: 'prefetch'|'prerender', * eagerness: 'conservative'|'moderate'|'eager', * }|null */ function wp_get_speculation_rules_configuration(): ?array { // By default, speculative loading is only enabled for sites with pretty permalinks when no user is logged in. if ( ! is_user_logged_in() && get_option( 'permalink_structure' ) ) { $config = array( 'mode' => 'auto', 'eagerness' => 'auto', ); } else { $config = null; } /** * Filters the way that speculation rules are configured. * * The Speculation Rules API is a web API that allows to automatically prefetch or prerender certain URLs on the * page, which can lead to near-instant page load times. This is also referred to as speculative loading. * * There are two aspects to the configuration: * * The "mode" (whether to "prefetch" or "prerender" URLs). * * The "eagerness" (whether to speculatively load URLs in an "eager", "moderate", or "conservative" way). * * By default, the speculation rules configuration is decided by WordPress Core ("auto"). This filter can be used * to force a certain configuration, which could for instance load URLs more or less eagerly. * * For logged-in users or for sites that are not configured to use pretty permalinks, the default value is `null`, * indicating that speculative loading is entirely disabled. * * @since 6.8.0 * @see https://developer.chrome.com/docs/web-platform/prerender-pages * * @param array<string, string>|null $config Associative array with 'mode' and 'eagerness' keys, or `null`. The * default value for both of the keys is 'auto'. Other possible values * for 'mode' are 'prefetch' and 'prerender'. Other possible values for * 'eagerness' are 'eager', 'moderate', and 'conservative'. The value * `null` is used to disable speculative loading entirely. */ $config = apply_filters( 'wp_speculation_rules_configuration', $config ); // Allow the value `null` to indicate that speculative loading is disabled. if ( null === $config ) { return null; } // Sanitize the configuration and replace 'auto' with current defaults. $defaults = wp_get_speculation_rules_default_configuration(); $default_mode = $defaults['mode']; $default_eagerness = $defaults['eagerness']; if ( ! is_array( $config ) ) { return array( 'mode' => $default_mode, 'eagerness' => $default_eagerness, ); } if ( ! isset( $config['mode'] ) || 'auto' === $config['mode'] || ! WP_Speculation_Rules::is_valid_mode( $config['mode'] ) ) { $config['mode'] = $default_mode; } if ( ! isset( $config['eagerness'] ) || 'auto' === $config['eagerness'] || ! WP_Speculation_Rules::is_valid_eagerness( $config['eagerness'] ) || // 'immediate' is a valid eagerness, but for safety WordPress does not allow it for document-level rules. 'immediate' === $config['eagerness'] ) { $config['eagerness'] = $default_eagerness; } return array( 'mode' => $config['mode'], 'eagerness' => $config['eagerness'], ); } /** * Returns the default speculation rules configuration that the value 'auto' resolves to. * * WordPress Core defaults to a mode of 'prefetch' and an eagerness of 'conservative'. Hosting providers can override * either default by way of the `WP_SPECULATIVE_LOADING_DEFAULT_MODE` and `WP_SPECULATIVE_LOADING_DEFAULT_EAGERNESS` * constants or environment variables. This only changes what the 'auto' value resolves to, so a plugin which supplies * an explicit mode or eagerness via the {@see 'wp_speculation_rules_configuration'} filter continues to take * precedence. * * Note that an eagerness of 'immediate' is not permitted as a default, since WordPress does not allow it for the * document-level rules that it generates. * * @since 7.1.0 * @access private * * @return array<string, string> Associative array with 'mode' and 'eagerness' keys. * @phpstan-return array{ * mode: 'prefetch'|'prerender', * eagerness: 'conservative'|'moderate'|'eager', * } */ function wp_get_speculation_rules_default_configuration(): array { $default_mode = 'prefetch'; $mode = wp_get_speculative_loading_override( 'WP_SPECULATIVE_LOADING_DEFAULT_MODE' ); if ( WP_Speculation_Rules::is_valid_mode( $mode ) ) { $default_mode = $mode; } $default_eagerness = 'conservative'; $eagerness = wp_get_speculative_loading_override( 'WP_SPECULATIVE_LOADING_DEFAULT_EAGERNESS' ); if ( WP_Speculation_Rules::is_valid_eagerness( $eagerness ) && // 'immediate' is a valid eagerness, but for safety WordPress does not allow it for document-level rules. 'immediate' !== $eagerness ) { $default_eagerness = $eagerness; } return array( 'mode' => $default_mode, 'eagerness' => $default_eagerness, ); } /** * Returns the value of a speculative loading override, as supplied by a constant or an environment variable. * * The constant takes precedence over the environment variable, consistent with {@see wp_get_environment_type()}. * * @since 7.1.0 * @access private * * @param string $name Name of the constant and environment variable to look up. * @return string|null The override value, or null if neither is set. */ function wp_get_speculative_loading_override( string $name ): ?string { $value = null; // Check if the environment variable has been set, if `getenv` is available on the system. if ( function_exists( 'getenv' ) ) { $has_env = getenv( $name ); if ( false !== $has_env ) { $value = $has_env; } } // Fetch the value from a constant, which overrides the environment variable. if ( defined( $name ) ) { $has_constant = constant( $name ); if ( is_string( $has_constant ) ) { $value = $has_constant; } } return $value; } /** * Returns the full speculation rules data based on the configuration. * * Plugins with features that rely on frontend URLs to exclude from prefetching or prerendering should use the * {@see 'wp_speculation_rules_href_exclude_paths'} filter to ensure those URL patterns are excluded. * * Additional speculation rules other than the default rule from WordPress Core can be provided by using the * {@see 'wp_load_speculation_rules'} action and amending the passed WP_Speculation_Rules object. * * @since 6.8.0 * @access private * * @return WP_Speculation_Rules|null Object representing the speculation rules to use, or null if speculative loading * is disabled in the current context. */ function wp_get_speculation_rules(): ?WP_Speculation_Rules { $configuration = wp_get_speculation_rules_configuration(); if ( null === $configuration ) { return null; } $mode = $configuration['mode']; $eagerness = $configuration['eagerness']; $prefixer = new WP_URL_Pattern_Prefixer(); $base_href_exclude_paths = array( $prefixer->prefix_path_pattern( '/wp-*.php', 'site' ), $prefixer->prefix_path_pattern( '/wp-admin/*', 'site' ), $prefixer->prefix_path_pattern( '/*', 'uploads' ), $prefixer->prefix_path_pattern( '/*', 'content' ), $prefixer->prefix_path_pattern( '/*', 'plugins' ), $prefixer->prefix_path_pattern( '/*', 'template' ), $prefixer->prefix_path_pattern( '/*', 'stylesheet' ), ); /* * If pretty permalinks are enabled, exclude any URLs with query parameters. * Otherwise, exclude specifically the URLs with a `_wpnonce` query parameter or any other query parameter * containing the word `nonce`. */ if ( get_option( 'permalink_structure' ) ) { $base_href_exclude_paths[] = $prefixer->prefix_path_pattern( '/*\\?(.+)', 'home' ); } else { $base_href_exclude_paths[] = $prefixer->prefix_path_pattern( '/*\\?*(^|&)*nonce*=*', 'home' ); } /** * Filters the paths for which speculative loading should be disabled. * * All paths should start in a forward slash, relative to the root document. The `*` can be used as a wildcard. * If the WordPress site is in a subdirectory, the exclude paths will automatically be prefixed as necessary. * * Note that WordPress always excludes certain path patterns such as `/wp-login.php` and `/wp-admin/*`, and those * cannot be modified using the filter. * * @since 6.8.0 * * @param string[] $href_exclude_paths Additional path patterns to disable speculative loading for. * @param string $mode Mode used to apply speculative loading. Either 'prefetch' or 'prerender'. */ $href_exclude_paths = (array) apply_filters( 'wp_speculation_rules_href_exclude_paths', array(), $mode ); $href_exclude_paths = array_filter( $href_exclude_paths, 'is_string' ); // Ensure that: // 1. There are no duplicates. // 2. The base paths cannot be removed. // 3. The array has sequential keys (i.e. array_is_list()). $href_exclude_paths = array_values( array_unique( array_merge( $base_href_exclude_paths, array_map( static function ( string $href_exclude_path ) use ( $prefixer ): string { return $prefixer->prefix_path_pattern( $href_exclude_path ); }, $href_exclude_paths ) ) ) ); $speculation_rules = new WP_Speculation_Rules(); $main_rule_conditions = array( // Include any URLs within the same site. array( 'href_matches' => $prefixer->prefix_path_pattern( '/*' ), ), // Except for excluded paths. array( 'not' => array( 'href_matches' => $href_exclude_paths, ), ), // Also exclude rel=nofollow links, as certain plugins use that on their links that perform an action. array( 'not' => array( 'selector_matches' => 'a[rel~="nofollow"]', ), ), // Also exclude links that are explicitly marked to opt out, either directly or via a parent element. array( 'not' => array( 'selector_matches' => ".no-{$mode}, .no-{$mode} a", ), ), ); // If using 'prerender', also exclude links that opt out of 'prefetch' because it's part of 'prerender'. if ( 'prerender' === $mode ) { $main_rule_conditions[] = array( 'not' => array( 'selector_matches' => '.no-prefetch, .no-prefetch a', ), ); } $speculation_rules->add_rule( $mode, 'main', array( 'source' => 'document', 'where' => array( 'and' => $main_rule_conditions, ), 'eagerness' => $eagerness, ) ); /** * Fires when speculation rules data is loaded, allowing to amend the rules. * * @since 6.8.0 * * @param WP_Speculation_Rules $speculation_rules Object representing the speculation rules to use. */ do_action( 'wp_load_speculation_rules', $speculation_rules ); return $speculation_rules; } /** * Prints the speculation rules. * * For browsers that do not support speculation rules yet, the `script[type="speculationrules"]` tag will be ignored. * * @since 6.8.0 * @access private */ function wp_print_speculation_rules(): void { $speculation_rules = wp_get_speculation_rules(); if ( null === $speculation_rules ) { return; } wp_print_inline_script_tag( (string) wp_json_encode( $speculation_rules, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ), array( 'type' => 'speculationrules' ) ); }