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<?php |
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/* |
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* This file is part of the Ariadne Component Library. |
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* |
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* (c) Muze <[email protected]> |
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* |
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* For the full copyright and license information, please view the LICENSE |
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* file that was distributed with this source code. |
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*/ |
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namespace arc\http; |
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/** |
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* This class contains static methods to help parse HTTP headers. |
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* @package arc\http |
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*/ |
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final class headers |
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{ |
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/** |
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* Parse response headers string from a HTTP request into an array of headers. e.g. |
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* [ 'Location' => 'http://www.example.com', ... ] |
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* When multiple headers with the same name are present, all values will form an array, in the order in which |
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* they are present in the source. |
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* @param string|string[] $headers The headers string to parse. |
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* @return array |
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*/ |
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public static function parse( $headers ) { |
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if ( !is_array($headers) && !$headers instanceof \ArrayObject ) { |
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$headers = array_filter( |
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array_map( 'trim', explode( "\n", (string) $headers ) ) |
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); |
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} |
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$result = []; |
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$currentName = ''; |
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foreach( $headers as $key => $header ) { |
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if ( !is_array($header) ) { |
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@list($name, $value) = array_map('trim', explode(':', $header, 2) ); |
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} else { |
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$name = $header; |
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$value = null; |
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} |
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if ( isset( $value ) ) { |
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$result = self::addHeader($result, $name, $value); |
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} else if (is_numeric($key)) { |
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if ( $currentName ) { |
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$result = self::addHeader($result, $currentName, $name); |
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} else { |
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$result[] = $name; |
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} |
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$name = $key; |
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} else { |
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$result = self::addHeader($result, $key, $name); |
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$name = $key; |
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} |
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$currentName = ( is_numeric($name) ? $currentName : $name ); |
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} |
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return $result; |
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} |
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/** |
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* Return an array with values from a Comma seperated header like Cache-Control or Accept |
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* e.g. 'max-age=300,public,no-store' |
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* results in |
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* [ 0 => [ 'max-age' => '300' ], 1 => [ 'public' => 'public' ], 2 => ['no-store' => 'no-store'] ] |
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* @param string $header |
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* @return array |
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*/ |
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public static function parseHeader($header) |
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{ |
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$header = (strpos($header, ':')!==false) ? explode(':', $header)[1] : $header; |
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$parts = array_map('trim', explode(',', $header)); |
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$header = []; |
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foreach ( $parts as $part ) { |
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$elements = array_map('trim', explode(';', $part)); |
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$result = []; |
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foreach ($elements as $element) { |
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@list($name, $value) = array_map('trim', explode( '=', $element)); |
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if ( !isset($value) ) { |
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$result['value'] = $name; |
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} else { |
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$result[$name] = (isset($value) ? $value : $name); |
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} |
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} |
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$header[] = $result; |
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} |
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return $header; |
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} |
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/** |
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* Merge multiple occurances of a comma seperated header |
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* @param array $headers |
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* @return array |
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*/ |
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public static function mergeHeaders( $headers ) |
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{ |
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$result = []; |
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if ( is_string($headers) ) { |
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$result = self::parseHeader( $headers ); |
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} else foreach ( $headers as $header ) { |
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if (is_string($header)) { |
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$header = self::parseHeader($header); |
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} |
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$result = array_merge( $result, $header ); |
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} |
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return $result; |
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} |
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/** |
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* Parse response headers to determine if and how long you may cache the response. Doesn't understand ETags. |
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* @param string|string[] $headers Headers string or array as returned by parse() |
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* @param bool $private Whether to store a private cache (true) or public cache image (false). Default is public. |
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* @return int The number of seconds you may cache this result starting from now. |
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*/ |
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public static function parseCacheTime( $headers, $private=false ) |
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{ |
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$result = null; |
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if ( is_string($headers) || ( !isset($headers['Cache-Control']) && !isset($headers['Expires']) ) ) { |
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$headers = \arc\http\headers::parse( $headers ); |
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} |
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if ( isset( $headers['Cache-Control'] ) ) { |
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$header = self::mergeHeaders( $headers['Cache-Control'] ); |
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$result = self::getCacheControlTime( $header, $private ); |
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} |
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if ( !isset($result) && isset( $headers['Expires'] ) ) { |
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$result = strtotime( self::getLastHeader( $headers['Expires'] ) ) - time(); |
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} |
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return (int) $result; |
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} |
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/** |
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* Parses Accept-* header and returns best matching value from the $acceptable list |
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* Takes into account the Q value and wildcards. Does not take into account other parameters |
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* currently ( e.g. text/html;level=1 ) |
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* @param array|string $header The Accept-* header (Accept:, Accept-Lang:, Accept-Encoding: etc.) |
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* @param array $acceptable List of acceptable values, in order of preference |
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* @return string |
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*/ |
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public static function accept( $header, $acceptable ) |
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{ |
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if ( is_string($header) ) { |
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$header = \arc\http\headers::parseHeader( $header ); |
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} |
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$ordered = self::orderByQuality($header); |
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foreach( $ordered as $value ) { |
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if ( self::isAcceptable($value['value'], $acceptable) ) { |
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return $value['value']; |
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} |
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} |
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} |
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public static function addHeader($headers, $name, $value) |
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{ |
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if ( !isset($headers[ $name]) ) { |
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// first entry for this header |
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$headers[ $name ] = $value; |
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} else if ( is_string($headers[ $name ]) ) { |
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// second header entry with same name |
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$headers[ $name ] = [ |
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$headers[ $name ], |
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$value |
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]; |
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} else { // third or later header entry with same name |
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$headers[ $name ][] = $value; |
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} |
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return $headers; |
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} |
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private static function getCacheControlTime( $header, $private ) |
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{ |
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$result = null; |
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$dontcache = false; |
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foreach ( $header as $value ) { |
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if ( isset($value['value']) ) { |
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switch($value['value']) { |
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case 'private': |
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if ( !$private ) { |
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$dontcache = true; |
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} |
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break; |
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case 'no-cache': |
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case 'no-store': |
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case 'must-revalidate': |
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case 'proxy-revalidate': |
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$dontcache = true; |
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break; |
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} |
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} else if ( isset($value['max-age']) || isset($value['s-maxage']) ) { |
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$maxage = (int) (isset($value['max-age']) ? $value['max-age'] : $value['s-maxage']); |
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if ( isset($result) ) { |
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$result = min($result, $maxage); |
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} else { |
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$result = $maxage; |
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} |
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} |
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} |
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if ( $dontcache ) { |
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$result = 0; |
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} |
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return $result; |
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} |
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private static function orderByQuality($header) |
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{ |
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$getQ = function($entry) { |
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$q = ( isset($entry['q']) ? floatval($entry['q']) : 1); |
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$name = $entry['value']; |
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if ( $name[ strlen($name)-1 ] == '*' || $name[0] == '*' ) { |
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$q -= 0.0001; // exact matches are preferred over wildcards |
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} |
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return $q; |
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}; |
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usort($header, function($a,$b) use ($getQ) { |
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return ($getQ($a)>$getQ($b) ? -1 : 1); |
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}); |
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return $header; |
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} |
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private static function pregEscape($string) { |
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$special = ".\\+'?[^]$(){}=!<>|:"; |
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// * and - are not included, since they are allowed in the accept mimetypes |
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return AddCSlashes($string, $special); |
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} |
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private static function isAcceptable($name, $acceptable) |
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{ |
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$name = str_replace('*', '.*', $name); |
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$result = preg_grep('|'.self::pregEscape($name).'|', $acceptable); |
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return current($result); |
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} |
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/** |
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* Return the last value sent for a specific header, uses the output of parse(). |
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* @param (mixed) $headers An array with multiple header strings or a single string. |
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* @return array|mixed |
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*/ |
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private static function getLastHeader($headers) { |
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if ( is_array($headers) ) { |
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return end($headers); |
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} |
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return $headers; |
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} |
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} |
If you suppress an error, we recommend checking for the error condition explicitly: