ezcache / includes / CriticalCSS.php

CriticalCSS.php in ezCache 2.5.2, at includes/CriticalCSS.php

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1	<?php
2	/**
3	* Critical CSS Generator
4	*
5	* Generates above-the-fold CSS and inlines it in the page <head>,
6	* deferring the full stylesheets to load asynchronously.
7	*
8	* @package Upress\EzCache
9	*/
10	namespace Upress\EzCache;
11
12	class CriticalCSS {
13
14	/** Storage directory for generated critical CSS files */
15	const STORAGE_DIR = 'ezcache/critical-css/';
16
17	/** Diagnostic API endpoint for critical CSS extraction */
18	const DIAG_PATH = '/critical-css';
19
20	/** Viewport height used for above-the-fold extraction (px) */
21	const VIEWPORT_HEIGHT = 1200;
22
23	private static $instance;
24	private $settings;
25	private $storage_path;
26
27	private function __construct() {
28	$this->settings = Settings::get_settings();
29	$this->storage_path = WP_CONTENT_DIR . '/' . self::STORAGE_DIR;
30	}
31
32	public static function instance() {
33	if ( ! self::$instance ) {
34	self::$instance = new self();
35	}
36	return self::$instance;
37	}
38
39	/**
40	* Register hooks
41	*/
42	public function register() {
43	if ( empty( $this->settings->enable_critical_css ) ) {
44	return;
45	}
46
47	if ( ! PremiumFeatures::is_premium() ) {
48	return;
49	}
50
51	add_action( 'wp_head', [ $this, 'inject_critical_css' ], 1 );
52	add_filter( 'style_loader_tag', [ $this, 'defer_stylesheet' ], 10, 4 );
53	}
54
55	/**
56	* Inject stored critical CSS for the current URL.
57	*/
58	public function inject_critical_css() {
59	$css = $this->get_critical_css( $this->get_url_pattern() );
60	if ( ! $css ) { return; }
61	echo '<style id="ezcache-critical-css">' . wp_strip_all_tags( $css ) . '</style>' . "\n";
62	}
63
64	/**
65	* Convert stylesheet link tags to async load + noscript fallback.
66	*/
67	public function defer_stylesheet( $tag, $handle, $href, $media ) {
68	// Don't defer admin or login stylesheets
69	if ( is_admin() ) { return $tag; }
70	$media_attr = $media ?: 'all';
71	$deferred = sprintf(
72	'<link rel="preload" href="%s" as="style" onload="this.onload=null;this.rel=\'stylesheet\';this.media=\'%s\'">' . "\n" .
73	'<noscript><link rel="stylesheet" href="%s" media="%s"></noscript>' . "\n",
74	esc_url( $href ), esc_attr( $media_attr ),
75	esc_url( $href ), esc_attr( $media_attr )
76	);
77	return $deferred;
78	}
79
80	/**
81	* Generate critical CSS for a URL using the diagnostic API.
82	*
83	* @param string $page_url Full URL of the page.
84	* @param string $pattern Storage pattern key (home, post, page, archive).
85	* @return array{success:bool, message:string, css:string}
86	*/
87	public function generate( $page_url, $pattern = null ) {
88	if ( ! PremiumFeatures::is_premium() ) {
89	return [ 'success' => false, 'message' => 'Premium required' ];
90	}
91
92	$diag_url = $this->get_diag_api_url();
93	if ( ! $diag_url ) {
94	return [ 'success' => false, 'message' => 'Diagnostic API not configured' ];
95	}
96
97	$response = wp_remote_post( $diag_url . self::DIAG_PATH, [
98	'timeout' => 30,
99	'body' => wp_json_encode( [
100	'url' => $page_url,
101	'viewport_height' => self::VIEWPORT_HEIGHT,
102	] ),
103	'headers' => [ 'Content-Type' => 'application/json' ],
104	'sslverify' => false,
105	] );
106
107	if ( is_wp_error( $response ) ) {
108	return [ 'success' => false, 'message' => $response->get_error_message() ];
109	}
110
111	$body = json_decode( wp_remote_retrieve_body( $response ), true );
112	if ( empty( $body['css'] ) ) {
113	return [ 'success' => false, 'message' => 'No CSS returned from API' ];
114	}
115
116	$pattern = $pattern ?: $this->get_url_pattern();
117	$this->save_critical_css( $pattern, $body['css'] );
118
119	return [ 'success' => true, 'message' => 'Critical CSS generated', 'css' => $body['css'] ];
120	}
121
122	/**
123	* Get stored critical CSS for a URL pattern.
124	*
125	* @param string $pattern
126	* @return string\|false
127	*/
128	public function get_critical_css( $pattern ) {
129	$file = $this->storage_path . sanitize_file_name( $pattern ) . '.css';
130	if ( file_exists( $file ) ) {
131	return file_get_contents( $file );
132	}
133	return false;
134	}
135
136	/**
137	* Save critical CSS for a pattern.
138	*
139	* @param string $pattern
140	* @param string $css
141	*/
142	public function save_critical_css( $pattern, $css ) {
143	wp_mkdir_p( $this->storage_path );
144	$file = $this->storage_path . sanitize_file_name( $pattern ) . '.css';
145	file_put_contents( $file, wp_strip_all_tags( $css ) );
146	}
147
148	/**
149	* Delete all stored critical CSS files.
150	*/
151	public function clear_all() {
152	if ( ! is_dir( $this->storage_path ) ) { return; }
153	$files = glob( $this->storage_path . '*.css' );
154	if ( $files ) {
155	foreach ( $files as $f ) { @unlink( $f ); }
156	}
157	}
158
159	/**
160	* Get a list of patterns that have generated critical CSS.
161	*
162	* @return array
163	*/
164	public function get_patterns() {
165	if ( ! is_dir( $this->storage_path ) ) { return []; }
166	$files = glob( $this->storage_path . '*.css' ) ?: [];
167	$patterns = [];
168	foreach ( $files as $f ) {
169	$patterns[] = basename( $f, '.css' );
170	}
171	return $patterns;
172	}
173
174	/**
175	* Determine a canonical pattern key for the current URL.
176	*
177	* @return string e.g. 'home', 'post', 'page', 'archive'
178	*/
179	public function get_url_pattern() {
180	if ( is_front_page() \|\| is_home() ) { return 'home'; }
181	if ( is_single() ) { return 'post'; }
182	if ( is_page() ) { return 'page'; }
183	if ( is_archive() ) { return 'archive'; }
184	return 'default';
185	}
186
187	/**
188	* Build the diagnostic API base URL from plugin settings.
189	*
190	* @return string\|false
191	*/
192	private function get_diag_api_url() {
193	// Try to find the local diagnostic API (Booting AI diagnostic server).
194	$diag_url = \get_option( 'ezcache_diag_api_url' );
195	if ( $diag_url ) {
196	return rtrim( $diag_url, '/' );
197	}
198	// Default: localhost diagnostic service
199	return 'http://localhost:8787';
200	}
201	}
202