woocommerce-pos / includes / Services / Local_Image_Resolver.php

Local_Image_Resolver.php in WCPOS – Point of Sale (POS) plugin for WooCommerce trunk, at includes/Services/Local_Image_Resolver.php

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1	<?php
2	/**
3	* Local image resolution for receipt rendering.
4	*
5	* Receipt templates carry logos as ordinary WordPress URLs, but nothing that
6	* renders a receipt may fetch a URL: the PDF path runs with Dompdf's remote
7	* access disabled, and the cloud-print raster runs inside a printer's job fetch,
8	* where an outbound HTTP call would stall the print.
9	*
10	* So local URLs are resolved to bytes on disk instead. Resolution is deliberately
11	* narrow — only the uploads directory, wp-content and this plugin's own directory
12	* are reachable, and every candidate path is realpath()-checked against those
13	* roots so a crafted `../` src cannot read outside them.
14	*
15	* Extracted from Pdf_Renderer, which still uses it for Dompdf's data-URI
16	* embedding, so both renderers resolve images the same way.
17	*
18	* @package WCPOS\WooCommercePOS\Services
19	*/
20
21	namespace WCPOS\WooCommercePOS\Services;
22
23	/**
24	* Local_Image_Resolver class.
25	*/
26	class Local_Image_Resolver {
27
28	/**
29	* Read the bytes an image src points at.
30	*
31	* Accepts a data URI (decoded in place) or a local WordPress URL/path.
32	* Remote URLs resolve to '' — they are never fetched.
33	*
34	* @param string $src Image source.
35	*
36	* @return string The image bytes, or '' when the src is not resolvable.
37	*/
38	public function bytes( string $src ): string {
39	$src = trim( $src );
40	if ( '' === $src ) {
41	return '';
42	}
43
44	if ( 1 === preg_match( '#^data:image/[a-z.+-]+;base64,#i', $src ) ) {
45	$decoded = base64_decode( (string) substr( $src, (int) strpos( $src, ',' ) + 1 ), true );
46
47	return false === $decoded ? '' : $decoded;
48	}
49
50	$path = $this->local_path( $src );
51	if ( null === $path ) {
52	return '';
53	}
54
55	$bytes = file_get_contents( $path ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- Local file read, not HTTP.
56
57	return false === $bytes ? '' : $bytes;
58	}
59
60	/**
61	* Convert a local image source to a data URI.
62	*
63	* @param string $src Image source.
64	*
65	* @return string\|null Data URI, or null when the source is not embeddable.
66	*/
67	public function data_uri( string $src ): ?string {
68	if ( '' === $src \|\| 0 === strpos( $src, 'data:' ) ) {
69	return null;
70	}
71
72	$path = $this->local_path( $src );
73	if ( null === $path ) {
74	return null;
75	}
76
77	$bytes = file_get_contents( $path ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- Local file read, not HTTP.
78	if ( false === $bytes \|\| '' === $bytes ) {
79	return null;
80	}
81
82	$mime = $this->mime_type( $path );
83	if ( null === $mime ) {
84	return null;
85	}
86
87	return 'data:' . $mime . ';base64,' . base64_encode( $bytes );
88	}
89
90	/**
91	* Resolve an image src to a readable local filesystem path.
92	*
93	* @param string $src Image source.
94	*
95	* @return string\|null Local path, or null when the src is external/unknown.
96	*/
97	public function local_path( string $src ): ?string {
98	$src = trim( $src );
99	$src = explode( '#', $src, 2 )[0];
100	$src = explode( '?', $src, 2 )[0];
101
102	if ( '' === $src ) {
103	return null;
104	}
105
106	$path = null;
107	if ( 0 === strpos( $src, '/' ) && 0 !== strpos( $src, '//' ) && \defined( 'ABSPATH' ) ) {
108	$path = wp_normalize_path( ABSPATH . ltrim( $src, '/' ) );
109	} else {
110	foreach ( $this->url_path_mappings() as $url_base => $path_base ) {
111	if ( 0 !== strpos( $src, $url_base ) ) {
112	continue;
113	}
114
115	$relative = ltrim( substr( $src, \strlen( $url_base ) ), '/\\' );
116	$path = wp_normalize_path( trailingslashit( $path_base ) . $relative );
117	break;
118	}
119	}
120
121	if ( null === $path \|\| ! $this->is_allowed_path( $path ) ) {
122	return null;
123	}
124
125	return ( is_readable( $path ) && is_file( $path ) ) ? $path : null;
126	}
127
128	/**
129	* The image MIME type of a local file, when it is one we render.
130	*
131	* @param string $path Local file path.
132	*
133	* @return string\|null
134	*/
135	public function mime_type( string $path ): ?string {
136	$extension = strtolower( (string) pathinfo( $path, PATHINFO_EXTENSION ) );
137
138	switch ( $extension ) {
139	case 'png':
140	return 'image/png';
141	case 'jpg':
142	case 'jpeg':
143	return 'image/jpeg';
144	case 'gif':
145	return 'image/gif';
146	case 'webp':
147	return 'image/webp';
148	case 'svg':
149	// Dompdf renders SVG, so PDF receipts with a vector logo depend on
150	// this. GD cannot decode it, so the raster emitter simply skips such
151	// an image rather than drawing a broken one — bytes() hands over the
152	// file either way and the caller decides.
153	return 'image/svg+xml';
154	default:
155	return null;
156	}
157	}
158
159	/**
160	* Build URL-to-path mappings for local WordPress assets.
161	*
162	* Longest URL base first, so a nested mapping wins over its parent.
163	*
164	* @return array<string,string>
165	*/
166	private function url_path_mappings(): array {
167	$uploads = wp_upload_dir();
168	$plugin = \dirname( __DIR__, 2 );
169
170	$mappings = array(
171	$uploads['baseurl'] => $uploads['basedir'],
172	content_url() => \defined( 'WP_CONTENT_DIR' ) ? WP_CONTENT_DIR : '',
173	plugins_url( '', $plugin . '/woocommerce-pos.php' ) => $plugin,
174	);
175
176	$normalized = array();
177	foreach ( $mappings as $url => $path ) {
178	if ( '' === $url \|\| '' === $path ) {
179	continue;
180	}
181	$normalized[ trailingslashit( $url ) ] = wp_normalize_path( $path );
182	}
183
184	uksort(
185	$normalized,
186	static function ( string $a, string $b ): int {
187	return \strlen( $b ) <=> \strlen( $a );
188	}
189	);
190
191	return $normalized;
192	}
193
194	/**
195	* Check that a resolved path stays within known local asset roots.
196	*
197	* @param string $path Resolved path.
198	*
199	* @return bool
200	*/
201	private function is_allowed_path( string $path ): bool {
202	$real_path = realpath( $path );
203	if ( false === $real_path ) {
204	return false;
205	}
206
207	$real_path = wp_normalize_path( $real_path );
208	foreach ( $this->allowed_roots() as $root ) {
209	if ( 0 === strpos( $real_path, trailingslashit( $root ) ) \|\| $real_path === $root ) {
210	return true;
211	}
212	}
213
214	return false;
215	}
216
217	/**
218	* Allowed local image roots.
219	*
220	* @return string[]
221	*/
222	private function allowed_roots(): array {
223	$uploads = wp_upload_dir();
224	$roots = array(
225	$uploads['basedir'],
226	\defined( 'WP_CONTENT_DIR' ) ? WP_CONTENT_DIR : '',
227	\dirname( __DIR__, 2 ),
228	);
229
230	return array_values(
231	array_filter(
232	array_map(
233	static function ( string $root ): string {
234	$real = realpath( $root );
235
236	return false === $real ? '' : wp_normalize_path( $real );
237	},
238	$roots
239	)
240	)
241	);
242	}
243	}
244