name : class-wp-http-encoding.php <?php /** * HTTP API: WP_Http_Encoding class * * @package WordPress * @subpackage HTTP * @since 4.4.0 */ /** * Core class used to implement deflate and gzip transfer encoding support for HTTP requests. * * Includes RFC 1950, RFC 1951, and RFC 1952. * * @since 2.8.0 */ #[AllowDynamicProperties] class WP_Http_Encoding { /** * Compress raw string using the deflate format. * * Supports the RFC 1951 standard. * * @since 2.8.0 * * @param string $raw String to compress. * @param int $level Optional. Compression level, 9 is highest. Default 9. * @param string $supports Optional, not used. When implemented it will choose * the right compression based on what the server supports. * @return string|false Compressed string on success, false on failure. */ public static function compress( $raw, $level = 9, $supports = null ) { return gzdeflate( $raw, $level ); } /** * Decompression of deflated string. * * Will attempt to decompress using the RFC 1950 standard, and if that fails * then the RFC 1951 standard deflate will be attempted. Finally, the RFC * 1952 standard gzip decode will be attempted. If all fail, then the * original compressed string will be returned. * * @since 2.8.0 * * @param string $compressed String to decompress. * @param int $length The optional length of the compressed data. * @return string|false Decompressed string on success, false on failure. */ public static function decompress( $compressed, $length = null ) { if ( empty( $compressed ) ) { return $compressed; } $decompressed = @gzinflate( $compressed ); if ( false !== $decompressed ) { return $decompressed; } $decompressed = self::compatible_gzinflate( $compressed ); if ( false !== $decompressed ) { return $decompressed; } $decompressed = @gzuncompress( $compressed ); if ( false !== $decompressed ) { return $decompressed; } if ( function_exists( 'gzdecode' ) ) { $decompressed = @gzdecode( $compressed ); if ( false !== $decompressed ) { return $decompressed; } } return $compressed; } /** * Decompression of deflated string while staying compatible with the majority of servers. * * Certain Servers will return deflated data with headers which PHP's gzinflate() * function cannot handle out of the box. The following function has been created from * various snippets on the gzinflate() PHP documentation. * * Warning: Magic numbers within. Due to the potential different formats that the compressed * data may be returned in, some "magic offsets" are needed to ensure proper decompression * takes place. For a simple pragmatic way to determine the magic offset in use, see: * https://core.trac.wordpress.org/ticket/18273 * * @since 2.8.1 * * @link https://core.trac.wordpress.org/ticket/18273 * @link https://www.php.net/manual/en/function.gzinflate.php#70875 * @link https://www.php.net/manual/en/function.gzinflate.php#77336 * * @param string $gz_data String to decompress. * @return string|false Decompressed string on success, false on failure. */ public static function compatible_gzinflate( $gz_data ) { // Compressed data might contain a full header, if so strip it for gzinflate(). if ( str_starts_with( $gz_data, "\x1f\x8b\x08" ) ) { $i = 10; $flg = ord( substr( $gz_data, 3, 1 ) ); if ( $flg > 0 ) { if ( $flg & 4 ) { list($xlen) = unpack( 'v', substr( $gz_data, $i, 2 ) ); $i = $i + 2 + $xlen; } if ( $flg & 8 ) { $i = strpos( $gz_data, "\0", $i ) + 1; } if ( $flg & 16 ) { $i = strpos( $gz_data, "\0", $i ) + 1; } if ( $flg & 2 ) { $i = $i + 2; } } $decompressed = @gzinflate( substr( $gz_data, $i, -8 ) ); if ( false !== $decompressed ) { return $decompressed; } } // Compressed data from java.util.zip.Deflater amongst others. $decompressed = @gzinflate( substr( $gz_data, 2 ) ); if ( false !== $decompressed ) { return $decompressed; } return false; } /** * What encoding types to accept and their priority values. * * @since 2.8.0 * * @param string $url * @param array $args * @return string Types of encoding to accept. */ public static function accept_encoding( $url, $args ) { $type = array(); $compression_enabled = self::is_available(); if ( ! $args['decompress'] ) { // Decompression specifically disabled. $compression_enabled = false; } elseif ( $args['stream'] ) { // Disable when streaming to file. $compression_enabled = false; } elseif ( isset( $args['limit_response_size'] ) ) { // If only partial content is being requested, we won't be able to decompress it. $compression_enabled = false; } if ( $compression_enabled ) { if ( function_exists( 'gzinflate' ) ) { $type[] = 'deflate;q=1.0'; } if ( function_exists( 'gzuncompress' ) ) { $type[] = 'compress;q=0.5'; } if ( function_exists( 'gzdecode' ) ) { $type[] = 'gzip;q=0.5'; } } /** * Filters the allowed encoding types. * * @since 3.6.0 * * @param string[] $type Array of what encoding types to accept and their priority values. * @param string $url URL of the HTTP request. * @param array $args HTTP request arguments. */ $type = apply_filters( 'wp_http_accept_encoding', $type, $url, $args ); return implode( ', ', $type ); } /** * What encoding the content used when it was compressed to send in the headers. * * @since 2.8.0 * * @return string Content-Encoding string to send in the header. */ public static function content_encoding() { return 'deflate'; } /** * Whether the content be decoded based on the headers. * * @since 2.8.0 * * @param array|string $headers All of the available headers. * @return bool */ public static function should_decode( $headers ) { if ( is_array( $headers ) ) { if ( array_key_exists( 'content-encoding', $headers ) && ! empty( $headers['content-encoding'] ) ) { return true; } } elseif ( is_string( $headers ) ) { return ( stripos( $headers, 'content-encoding:' ) !== false ); } return false; } /** * Whether decompression and compression are supported by the PHP version. * * Each function is tested instead of checking for the zlib extension, to * ensure that the functions all exist in the PHP version and aren't * disabled. * * @since 2.8.0 * * @return bool */ public static function is_available() { return ( function_exists( 'gzuncompress' ) || function_exists( 'gzdeflate' ) || function_exists( 'gzinflate' ) ); } }