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Member "wordpress/wp-includes/class-wp-http-encoding.php" (15 Jan 2021, 6654 Bytes) of package /linux/www/wordpress-5.7-RC1.tar.gz:
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1 <?php
2 /**
3 * HTTP API: WP_Http_Encoding class
4 *
5 * @package WordPress
6 * @subpackage HTTP
7 * @since 4.4.0
8 */
9
10 /**
11 * Core class used to implement deflate and gzip transfer encoding support for HTTP requests.
12 *
13 * Includes RFC 1950, RFC 1951, and RFC 1952.
14 *
15 * @since 2.8.0
16 */
17 class WP_Http_Encoding {
18
19 /**
20 * Compress raw string using the deflate format.
21 *
22 * Supports the RFC 1951 standard.
23 *
24 * @since 2.8.0
25 *
26 * @param string $raw String to compress.
27 * @param int $level Optional. Compression level, 9 is highest. Default 9.
28 * @param string $supports Optional, not used. When implemented it will choose
29 * the right compression based on what the server supports.
30 * @return string|false Compressed string on success, false on failure.
31 */
32 public static function compress( $raw, $level = 9, $supports = null ) {
33 return gzdeflate( $raw, $level );
34 }
35
36 /**
37 * Decompression of deflated string.
38 *
39 * Will attempt to decompress using the RFC 1950 standard, and if that fails
40 * then the RFC 1951 standard deflate will be attempted. Finally, the RFC
41 * 1952 standard gzip decode will be attempted. If all fail, then the
42 * original compressed string will be returned.
43 *
44 * @since 2.8.0
45 *
46 * @param string $compressed String to decompress.
47 * @param int $length The optional length of the compressed data.
48 * @return string|false Decompressed string on success, false on failure.
49 */
50 public static function decompress( $compressed, $length = null ) {
51
52 if ( empty( $compressed ) ) {
53 return $compressed;
54 }
55
56 $decompressed = @gzinflate( $compressed );
57 if ( false !== $decompressed ) {
58 return $decompressed;
59 }
60
61 $decompressed = self::compatible_gzinflate( $compressed );
62 if ( false !== $decompressed ) {
63 return $decompressed;
64 }
65
66 $decompressed = @gzuncompress( $compressed );
67 if ( false !== $decompressed ) {
68 return $decompressed;
69 }
70
71 if ( function_exists( 'gzdecode' ) ) {
72 $decompressed = @gzdecode( $compressed );
73
74 if ( false !== $decompressed ) {
75 return $decompressed;
76 }
77 }
78
79 return $compressed;
80 }
81
82 /**
83 * Decompression of deflated string while staying compatible with the majority of servers.
84 *
85 * Certain Servers will return deflated data with headers which PHP's gzinflate()
86 * function cannot handle out of the box. The following function has been created from
87 * various snippets on the gzinflate() PHP documentation.
88 *
89 * Warning: Magic numbers within. Due to the potential different formats that the compressed
90 * data may be returned in, some "magic offsets" are needed to ensure proper decompression
91 * takes place. For a simple progmatic way to determine the magic offset in use, see:
92 * https://core.trac.wordpress.org/ticket/18273
93 *
94 * @since 2.8.1
95 *
96 * @link https://core.trac.wordpress.org/ticket/18273
97 * @link https://www.php.net/manual/en/function.gzinflate.php#70875
98 * @link https://www.php.net/manual/en/function.gzinflate.php#77336
99 *
100 * @param string $gzData String to decompress.
101 * @return string|false Decompressed string on success, false on failure.
102 */
103 public static function compatible_gzinflate( $gzData ) {
104
105 // Compressed data might contain a full header, if so strip it for gzinflate().
106 if ( "\x1f\x8b\x08" === substr( $gzData, 0, 3 ) ) {
107 $i = 10;
108 $flg = ord( substr( $gzData, 3, 1 ) );
109 if ( $flg > 0 ) {
110 if ( $flg & 4 ) {
111 list($xlen) = unpack( 'v', substr( $gzData, $i, 2 ) );
112 $i = $i + 2 + $xlen;
113 }
114 if ( $flg & 8 ) {
115 $i = strpos( $gzData, "\0", $i ) + 1;
116 }
117 if ( $flg & 16 ) {
118 $i = strpos( $gzData, "\0", $i ) + 1;
119 }
120 if ( $flg & 2 ) {
121 $i = $i + 2;
122 }
123 }
124 $decompressed = @gzinflate( substr( $gzData, $i, -8 ) );
125 if ( false !== $decompressed ) {
126 return $decompressed;
127 }
128 }
129
130 // Compressed data from java.util.zip.Deflater amongst others.
131 $decompressed = @gzinflate( substr( $gzData, 2 ) );
132 if ( false !== $decompressed ) {
133 return $decompressed;
134 }
135
136 return false;
137 }
138
139 /**
140 * What encoding types to accept and their priority values.
141 *
142 * @since 2.8.0
143 *
144 * @param string $url
145 * @param array $args
146 * @return string Types of encoding to accept.
147 */
148 public static function accept_encoding( $url, $args ) {
149 $type = array();
150 $compression_enabled = self::is_available();
151
152 if ( ! $args['decompress'] ) { // Decompression specifically disabled.
153 $compression_enabled = false;
154 } elseif ( $args['stream'] ) { // Disable when streaming to file.
155 $compression_enabled = false;
156 } elseif ( isset( $args['limit_response_size'] ) ) { // If only partial content is being requested, we won't be able to decompress it.
157 $compression_enabled = false;
158 }
159
160 if ( $compression_enabled ) {
161 if ( function_exists( 'gzinflate' ) ) {
162 $type[] = 'deflate;q=1.0';
163 }
164
165 if ( function_exists( 'gzuncompress' ) ) {
166 $type[] = 'compress;q=0.5';
167 }
168
169 if ( function_exists( 'gzdecode' ) ) {
170 $type[] = 'gzip;q=0.5';
171 }
172 }
173
174 /**
175 * Filters the allowed encoding types.
176 *
177 * @since 3.6.0
178 *
179 * @param string[] $type Array of what encoding types to accept and their priority values.
180 * @param string $url URL of the HTTP request.
181 * @param array $args HTTP request arguments.
182 */
183 $type = apply_filters( 'wp_http_accept_encoding', $type, $url, $args );
184
185 return implode( ', ', $type );
186 }
187
188 /**
189 * What encoding the content used when it was compressed to send in the headers.
190 *
191 * @since 2.8.0
192 *
193 * @return string Content-Encoding string to send in the header.
194 */
195 public static function content_encoding() {
196 return 'deflate';
197 }
198
199 /**
200 * Whether the content be decoded based on the headers.
201 *
202 * @since 2.8.0
203 *
204 * @param array|string $headers All of the available headers.
205 * @return bool
206 */
207 public static function should_decode( $headers ) {
208 if ( is_array( $headers ) ) {
209 if ( array_key_exists( 'content-encoding', $headers ) && ! empty( $headers['content-encoding'] ) ) {
210 return true;
211 }
212 } elseif ( is_string( $headers ) ) {
213 return ( stripos( $headers, 'content-encoding:' ) !== false );
214 }
215
216 return false;
217 }
218
219 /**
220 * Whether decompression and compression are supported by the PHP version.
221 *
222 * Each function is tested instead of checking for the zlib extension, to
223 * ensure that the functions all exist in the PHP version and aren't
224 * disabled.
225 *
226 * @since 2.8.0
227 *
228 * @return bool
229 */
230 public static function is_available() {
231 return ( function_exists( 'gzuncompress' ) || function_exists( 'gzdeflate' ) || function_exists( 'gzinflate' ) );
232 }
233 }