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<?php |
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|
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namespace Upress\EzCache; |
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|
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/** |
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* Front-end performance optimizations inspired by WP Rocket. |
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* |
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* Each optimization is opt-in via the plugin settings. Heavy lifting that |
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* needs to alter the HTML of cached pages happens through buffer filters that |
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* run before the cache file is written, so the work only happens once per |
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* cache generation. |
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*/ |
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class Optimizations { |
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|
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/** @var object */ |
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protected $settings; |
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|
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public function __construct() { |
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$this->settings = Settings::get_settings(); |
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|
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add_action( 'init', [ $this, 'maybe_control_heartbeat' ], 1 ); |
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add_filter( 'heartbeat_settings', [ $this, 'filter_heartbeat_settings' ] ); |
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|
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add_action( 'wp_head', [ $this, 'output_resource_hints' ], 1 ); |
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|
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add_filter( 'ezcache_before_save_cache', [ $this, 'lazy_load_html' ], 20 ); |
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add_filter( 'ezcache_before_save_cache', [ $this, 'remove_query_strings' ], 30 ); |
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add_filter( 'ezcache_before_save_cache', [ $this, 'rewrite_cdn_urls' ], 40 ); |
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add_filter( 'ezcache_before_save_cache', [ $this, 'defer_js' ], 50 ); |
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} |
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|
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/** |
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* Disable or throttle the WP Heartbeat API based on settings. |
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*/ |
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public function maybe_control_heartbeat() { |
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if ( empty( $this->settings->heartbeat_control ) ) { |
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return; |
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} |
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|
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$mode = isset( $this->settings->heartbeat_mode ) ? $this->settings->heartbeat_mode : 'reduce'; |
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|
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if ( 'disable' === $mode ) { |
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wp_deregister_script( 'heartbeat' ); |
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} |
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} |
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|
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/** |
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* Slow the heartbeat tick interval down (default 60s) when "reduce" mode is on. |
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* |
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* @param array $settings |
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* @return array |
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*/ |
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public function filter_heartbeat_settings( $settings ) { |
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if ( empty( $this->settings->heartbeat_control ) ) { |
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return $settings; |
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} |
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|
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$mode = isset( $this->settings->heartbeat_mode ) ? $this->settings->heartbeat_mode : 'reduce'; |
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|
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if ( 'reduce' === $mode ) { |
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$settings['interval'] = 60; |
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$settings['minimalInterval'] = 60; |
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} |
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|
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return $settings; |
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} |
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|
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/** |
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* Output `<link rel="dns-prefetch">` and `<link rel="preconnect">` tags |
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* configured by the user. |
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*/ |
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public function output_resource_hints() { |
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if ( ! empty( $this->settings->dns_prefetch ) ) { |
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$hosts = preg_split( "/\r\n|\r|\n/", trim( $this->settings->dns_prefetch ), -1, PREG_SPLIT_NO_EMPTY ); |
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foreach ( $hosts as $host ) { |
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$host = esc_url( trim( $host ) ); |
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if ( $host ) { |
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echo "<link rel='dns-prefetch' href='" . esc_attr( $host ) . "'>\n"; |
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} |
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} |
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} |
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|
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if ( ! empty( $this->settings->preconnect ) ) { |
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$hosts = preg_split( "/\r\n|\r|\n/", trim( $this->settings->preconnect ), -1, PREG_SPLIT_NO_EMPTY ); |
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foreach ( $hosts as $host ) { |
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$host = esc_url( trim( $host ) ); |
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if ( $host ) { |
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echo "<link rel='preconnect' href='" . esc_attr( $host ) . "' crossorigin>\n"; |
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} |
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} |
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} |
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} |
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|
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/** |
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* Add native lazy-loading to images and iframes that don't already opt out. |
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* |
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* @param string $html |
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* @return string |
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*/ |
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public function lazy_load_html( $html ) { |
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if ( empty( $this->settings->lazy_load_images ) && empty( $this->settings->lazy_load_iframes ) ) { |
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return $html; |
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} |
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|
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if ( ! empty( $this->settings->lazy_load_images ) ) { |
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$html = preg_replace_callback( |
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'#<img\b([^>]*)>#i', |
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function ( $match ) { |
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$attrs = $match[1]; |
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if ( false !== stripos( $attrs, 'data-no-lazy' ) || preg_match( '/loading\s*=\s*["\'][^"\']*["\']/i', $attrs ) ) { |
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return $match[0]; |
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} |
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return '<img loading="lazy" decoding="async"' . $attrs . '>'; |
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}, |
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$html |
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); |
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} |
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|
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if ( ! empty( $this->settings->lazy_load_iframes ) ) { |
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$html = preg_replace_callback( |
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'#<iframe\b([^>]*)>#i', |
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function ( $match ) { |
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$attrs = $match[1]; |
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if ( false !== stripos( $attrs, 'data-no-lazy' ) || preg_match( '/loading\s*=\s*["\'][^"\']*["\']/i', $attrs ) ) { |
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return $match[0]; |
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} |
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return '<iframe loading="lazy"' . $attrs . '>'; |
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}, |
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$html |
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); |
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} |
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|
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return $html; |
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} |
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|
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/** |
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* Remove the `?ver=` query string from local static asset URLs to improve |
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* proxy/CDN cacheability. |
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* |
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* @param string $html |
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* @return string |
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*/ |
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public function remove_query_strings( $html ) { |
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if ( empty( $this->settings->remove_query_strings ) ) { |
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return $html; |
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} |
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|
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$home_host = preg_quote( wp_parse_url( home_url(), PHP_URL_HOST ), '#' ); |
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|
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return preg_replace_callback( |
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'#(["\'])((?:https?:)?//' . $home_host . '/[^"\']+\.(?:css|js))\?[^"\']*\1#i', |
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function ( $match ) { |
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return $match[1] . $match[2] . $match[1]; |
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}, |
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$html |
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); |
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} |
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|
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/** |
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* Rewrite local static URLs to point at the configured CDN host. |
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* |
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* @param string $html |
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* @return string |
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*/ |
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public function rewrite_cdn_urls( $html ) { |
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if ( empty( $this->settings->cdn_enabled ) || empty( $this->settings->cdn_url ) ) { |
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return $html; |
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} |
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|
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$cdn = untrailingslashit( $this->settings->cdn_url ); |
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$cdn = preg_replace( '#^https?:#', '', $cdn ); |
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|
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$home_url = home_url(); |
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$home_no_proto = preg_replace( '#^https?:#', '', $home_url ); |
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$home_no_proto = rtrim( $home_no_proto, '/' ); |
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|
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// Rewrite /wp-content/ and /wp-includes/ URLs. |
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$pattern = '#(["\'(=\s])((?:https?:)?' . preg_quote( $home_no_proto, '#' ) . ')?(/wp-content/(?:uploads|themes|plugins)/[^"\'\s)]+\.(?:jpg|jpeg|png|gif|webp|svg|css|js|woff|woff2|ttf|eot|ico))#i'; |
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|
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return preg_replace_callback( |
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$pattern, |
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function ( $match ) use ( $cdn ) { |
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return $match[1] . $cdn . $match[3]; |
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}, |
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$html |
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); |
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} |
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|
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/** |
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* Add `defer` to local script tags to reduce render-blocking JS. |
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* |
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* @param string $html |
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* @return string |
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*/ |
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public function defer_js( $html ) { |
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if ( empty( $this->settings->defer_js ) ) { |
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return $html; |
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} |
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|
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$excluded = [ 'jquery-core', 'jquery-migrate', 'jquery.js' ]; |
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if ( ! empty( $this->settings->defer_js_exclusions ) ) { |
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$excluded = array_merge( |
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$excluded, |
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preg_split( "/\r\n|\r|\n/", trim( $this->settings->defer_js_exclusions ), -1, PREG_SPLIT_NO_EMPTY ) |
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); |
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} |
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|
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return preg_replace_callback( |
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'#<script\b([^>]*?)src=(["\'])([^"\']+)\2([^>]*)></script>#i', |
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function ( $match ) use ( $excluded ) { |
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$attrs_before = $match[1]; |
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$src = $match[3]; |
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$attrs_after = $match[4]; |
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$all_attrs = $attrs_before . ' ' . $attrs_after; |
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|
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// Already deferred / async / module. |
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if ( preg_match( '/\b(defer|async|type\s*=\s*["\']?module)\b/i', $all_attrs ) ) { |
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return $match[0]; |
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} |
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|
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foreach ( $excluded as $needle ) { |
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$needle = trim( $needle ); |
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if ( '' !== $needle && false !== strpos( $src, $needle ) ) { |
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return $match[0]; |
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} |
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} |
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|
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return '<script' . $attrs_before . 'defer src=' . $match[2] . $src . $match[2] . $attrs_after . '></script>'; |
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}, |
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$html |
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); |
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} |
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} |
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|
