easyfonts / src / Frontend / SmartPreload.php

SmartPreload.php in EasyFonts – Host Google Fonts Locally, Fast & Auto-Optimize, GDPR Compliant 2.0.2, at src/Frontend/SmartPreload.php

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1	<?php
2	/**
3	* Smart preload.
4	*
5	* Emits <link rel="preload"> for the font faces that render ABOVE THE FOLD on
6	* the current page, so the browser fetches them as early as possible. Preload
7	* is a scarce resource — preloading a font that isn't critical (or isn't even
8	* on the page) competes with the hero content — so the set is built narrowly:
9	*
10	* 1. PER-ROUTE above-the-fold families — measured by the beacon for THIS
11	* route. A font above the fold only on one page is preloaded only there.
12	* 2. GLOBAL above-the-fold families — families that are above the fold on
13	* every route where they render (e.g. the body/heading font). Their answer
14	* is the same everywhere, so they're preloaded wherever present without any
15	* per-route lookup (the cheap path the site-wide fonts take).
16	* 3. USER-FORCED families — variants the user toggled to "always preload".
17	*
18	* Every candidate is intersected with the faces actually emitted on this page
19	* (Consolidator::touched), and resolved to the file that is genuinely hosted —
20	* so a font is never preloaded on a page that doesn't use it, and a face the
21	* beacon reported at a weight we don't host still resolves to the right file.
22	*
23	* @package EasyFonts
24	*/
25
26	namespace EasyFonts\Frontend;
27
28	use EasyFonts\Detect\Consolidator;
29	use EasyFonts\Fonts\Registry;
30	use EasyFonts\Fonts\Storage;
31	use EasyFonts\Fonts\UsageTracker;
32	use EasyFonts\Settings;
33
34	defined( 'ABSPATH' ) \|\| exit;
35
36	/**
37	* Builds deduped, page-scoped preload link markup.
38	*/
39	class SmartPreload {
40
41	/**
42	* @var Registry
43	*/
44	private Registry $registry;
45
46	/**
47	* @var Storage
48	*/
49	private Storage $storage;
50
51	/**
52	* Constructor.
53	*/
54	public function __construct() {
55	$this->registry = new Registry();
56	$this->storage = new Storage();
57	}
58
59	/**
60	* Build preload markup for the current request.
61	*
62	* @param string $route Canonical route (path) of the current page.
63	* @param string $device 'mobile'\|'desktop'\|'any' (reserved; matching is family-level).
64	* @param array<string,bool> $present_families Lowercased families emitted on this page (from Consolidator::touched).
65	* @param array<string,bool> $above_fold Lowercased families measured above the fold on THIS route.
66	* @return string
67	*/
68	public function build( string $route = '', string $device = 'any', array $present_families = array(), array $above_fold = array() ): string {
69	if ( ! Settings::get( 'smart_preload', 1 ) ) {
70	return '';
71	}
72
73	// Families that should preload here: this route's above-the-fold set,
74	// plus the uniformly-above-the-fold (global) set. The global set is the
75	// "skip per-route checking" path — its members preload wherever present.
76	$want = $above_fold;
77
78	foreach ( ( new UsageTracker() )->global_preload_families() as $fam => $_ ) {
79	$want[ $fam ] = true;
80	}
81
82	$cap = max( 1, (int) apply_filters( 'easyfonts_preload_cap', 6 ) );
83
84	$links = '';
85	$seen = array();
86	$count = 0;
87
88	// 1. Above-the-fold (per-route + global): preload the faces this page
89	// actually emits for those families — using the hosted variant, so a
90	// faux-bold/weight-mismatch report still resolves to a real file.
91	foreach ( Consolidator::touched() as $t ) {
92	if ( $count >= $cap ) {
93	break;
94	}
95
96	$fam = strtolower( (string) $t['family'] );
97
98	if ( empty( $want[ $fam ] ) ) {
99	continue;
100	}
101
102	$file = $this->registry->resolve_preload_file( (string) $t['family'], (string) $t['weight'], (string) $t['style'] );
103
104	if ( $this->emit_link( $file, $seen, $links ) ) {
105	$count++;
106	}
107	}
108
109	// 2. User-forced "always preload" variants, intersected with the page.
110	$gate = ! empty( $present_families );
111
112	foreach ( $this->registry->preload_targets() as $u ) {
113	if ( $count >= $cap ) {
114	break;
115	}
116
117	if ( $gate && empty( $present_families[ strtolower( (string) $u['family'] ) ] ) ) {
118	continue; // forced font isn't on this page — don't preload here.
119	}
120
121	if ( $this->emit_link( $u['file'], $seen, $links ) ) {
122	$count++;
123	}
124	}
125
126	return $links;
127	}
128
129	/**
130	* Append a preload <link> for a hosted file, deduping by file and skipping
131	* anything missing on disk. Returns true when a link was added.
132	*
133	* @param string\|null $file Font filename.
134	* @param array<string,bool> $seen Dedupe set (by reference).
135	* @param string $links Accumulated markup (by reference).
136	* @return bool
137	*/
138	private function emit_link( ?string $file, array &$seen, string &$links ): bool {
139	$file = (string) $file;
140
141	if ( '' === $file \|\| isset( $seen[ $file ] ) \|\| ! $this->storage->exists( $file ) ) {
142	return false;
143	}
144
145	$seen[ $file ] = true;
146
147	$url = add_query_arg( 'ver', Settings::buster(), $this->storage->url( $file ) );
148	$links .= sprintf(
149	'<link rel="preload" href="%s" as="font" type="%s" crossorigin>' . "\n",
150	esc_url( $url ),
151	esc_attr( $this->mime_for( $file ) )
152	);
153
154	return true;
155	}
156
157	/**
158	* MIME for a font file.
159	*
160	* @param string $file Filename.
161	* @return string
162	*/
163	private function mime_for( string $file ): string {
164	$ext = strtolower( (string) pathinfo( $file, PATHINFO_EXTENSION ) );
165
166	$map = array(
167	'woff2' => 'font/woff2',
168	'woff' => 'font/woff',
169	'ttf' => 'font/ttf',
170	'otf' => 'font/otf',
171	);
172
173	return $map[ $ext ] ?? 'font/woff2';
174	}
175	}
176