Ariadne-CMS /
arc-web
Complex classes like headers often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use headers, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 18 | final class headers |
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| 19 | { |
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| 20 | |||
| 21 | /** |
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| 22 | * Parse response headers string from a HTTP request into an array of headers. e.g. |
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| 23 | * [ 'Location' => 'http://www.example.com', ... ] |
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| 24 | * When multiple headers with the same name are present, all values will form an array, in the order in which |
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| 25 | * they are present in the source. |
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| 26 | * @param string|string[] $headers The headers string to parse. |
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| 27 | * @return array |
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| 28 | */ |
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| 29 | 14 | public static function parse( $headers ) { |
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| 30 | 14 | if ( !is_array($headers) && !$headers instanceof \ArrayObject ) { |
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| 31 | 10 | $headers = array_filter( |
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| 32 | 10 | array_map( 'trim', explode( "\n", (string) $headers ) ) |
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| 33 | ); |
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| 34 | } |
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| 35 | 14 | $result = []; |
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| 36 | 14 | $currentName = ''; |
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| 37 | 14 | foreach( $headers as $key => $header ) { |
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| 38 | 14 | if ( !is_array($header) ) { |
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| 39 | 14 | @list($name, $value) = array_map('trim', explode(':', $header, 2) ); |
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| 40 | } else { |
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| 41 | $name = $header; |
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| 42 | $value = null; |
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| 43 | } |
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| 44 | 14 | if ( isset( $value ) ) { |
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| 45 | 14 | $result = self::addHeader($result, $name, $value); |
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| 46 | 12 | } else if (is_numeric($key)) { |
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| 47 | 12 | if ( $currentName ) { |
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| 48 | 2 | $result = self::addHeader($result, $currentName, $name); |
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| 49 | } else { |
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| 50 | 12 | $result[] = $name; |
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| 51 | } |
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| 52 | 12 | $name = $key; |
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| 53 | } else { |
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| 54 | $result = self::addHeader($result, $key, $name); |
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| 55 | $name = $key; |
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| 56 | } |
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| 57 | 14 | $currentName = ( is_numeric($name) ? $currentName : $name ); |
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| 58 | } |
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| 59 | 14 | return $result; |
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| 60 | } |
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| 61 | |||
| 62 | /** |
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| 63 | * Return an array with values from a Comma seperated header like Cache-Control or Accept |
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| 64 | * e.g. 'max-age=300,public,no-store' |
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| 65 | * results in |
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| 66 | * [ 0 => [ 'max-age' => '300' ], 1 => [ 'public' => 'public' ], 2 => ['no-store' => 'no-store'] ] |
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| 67 | * @param string $header |
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| 68 | * @return array |
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| 69 | */ |
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| 70 | 12 | public static function parseHeader($header) |
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| 71 | { |
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| 72 | 12 | $header = (strpos($header, ':')!==false) ? explode(':', $header)[1] : $header; |
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| 73 | 12 | $parts = array_map('trim', explode(',', $header)); |
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| 74 | 12 | $header = []; |
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| 75 | 12 | foreach ( $parts as $part ) { |
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| 76 | 12 | $elements = array_map('trim', explode(';', $part)); |
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| 77 | 12 | $result = []; |
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| 78 | 12 | foreach ($elements as $element) { |
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| 79 | 12 | @list($name, $value) = array_map('trim', explode( '=', $element)); |
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| 80 | 12 | if ( !isset($value) ) { |
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| 81 | 12 | $result['value'] = $name; |
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| 82 | } else { |
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| 83 | 12 | $result[$name] = (isset($value) ? $value : $name); |
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| 84 | } |
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| 85 | } |
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| 86 | 12 | $header[] = $result; |
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| 87 | } |
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| 88 | 12 | return $header; |
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| 89 | } |
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| 90 | |||
| 91 | /** |
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| 92 | * Merge multiple occurances of a comma seperated header |
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| 93 | * @param array $headers |
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| 94 | * @return array |
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| 95 | */ |
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| 96 | 10 | public static function mergeHeaders( $headers ) |
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| 97 | { |
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| 98 | 10 | $result = []; |
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| 99 | 10 | if ( is_string($headers) ) { |
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| 100 | 6 | $result = self::parseHeader( $headers ); |
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| 101 | 4 | } else foreach ( $headers as $header ) { |
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| 102 | 4 | if (is_string($header)) { |
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| 103 | 4 | $header = self::parseHeader($header); |
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| 104 | } |
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| 105 | 4 | $result = array_merge( $result, $header ); |
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| 106 | } |
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| 107 | 10 | return $result; |
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| 108 | } |
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| 109 | |||
| 110 | /** |
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| 111 | * Parse response headers to determine if and how long you may cache the response. Doesn't understand ETags. |
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| 112 | * @param string|string[] $headers Headers string or array as returned by parse() |
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| 113 | * @param bool $private Whether to store a private cache (true) or public cache image (false). Default is public. |
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| 114 | * @return int The number of seconds you may cache this result starting from now. |
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| 115 | */ |
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| 116 | 12 | public static function parseCacheTime( $headers, $private=false ) |
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| 117 | { |
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| 118 | 12 | $result = null; |
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| 119 | 12 | if ( is_string($headers) || ( !isset($headers['Cache-Control']) && !isset($headers['Expires']) ) ) { |
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| 120 | 2 | $headers = \arc\http\headers::parse( $headers ); |
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| 121 | } |
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| 122 | 12 | if ( isset( $headers['Cache-Control'] ) ) { |
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| 123 | 10 | $header = self::mergeHeaders( $headers['Cache-Control'] ); |
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| 124 | 10 | $result = self::getCacheControlTime( $header, $private ); |
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| 125 | } |
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| 126 | 12 | if ( !isset($result) && isset( $headers['Expires'] ) ) { |
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| 127 | 2 | $result = strtotime( self::getLastHeader( $headers['Expires'] ) ) - time(); |
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| 128 | } |
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| 129 | 12 | return (int) $result; |
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| 130 | } |
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| 131 | |||
| 132 | /** |
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| 133 | * Parses Accept-* header and returns best matching value from the $acceptable list |
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| 134 | * Takes into account the Q value and wildcards. Does not take into account other parameters |
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| 135 | * currently ( e.g. text/html;level=1 ) |
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| 136 | * @param array|string $header The Accept-* header (Accept:, Accept-Lang:, Accept-Encoding: etc.) |
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| 137 | * @param array $acceptable List of acceptable values, in order of preference |
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| 138 | * @return string |
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| 139 | */ |
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| 140 | 2 | public static function accept( $header, $acceptable ) |
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| 141 | { |
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| 142 | 2 | if ( is_string($header) ) { |
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| 143 | 2 | $header = \arc\http\headers::parseHeader( $header ); |
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| 144 | } |
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| 145 | 2 | $ordered = self::orderByQuality($header); |
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| 146 | 2 | foreach( $ordered as $value ) { |
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| 147 | 2 | if ( self::isAcceptable($value['value'], $acceptable) ) { |
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| 148 | 2 | return $value['value']; |
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| 149 | } |
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| 150 | } |
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| 151 | } |
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| 152 | |||
| 153 | 14 | private static function addHeader($headers, $name, $value) |
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| 154 | { |
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| 155 | 14 | if ( !isset($headers[ $name]) ) { |
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| 156 | // first entry for this header |
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| 157 | 14 | $headers[ $name ] = $value; |
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| 158 | 6 | } else if ( is_string($headers[ $name ]) ) { |
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| 159 | // second header entry with same name |
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| 160 | 6 | $headers[ $name ] = [ |
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| 161 | 6 | $headers[ $name ], |
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| 162 | 6 | $value |
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| 163 | ]; |
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| 164 | } else { // third or later header entry with same name |
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| 165 | 2 | $headers[ $name ][] = $value; |
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| 166 | } |
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| 167 | 14 | return $headers; |
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| 168 | } |
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| 169 | |||
| 170 | 10 | private static function getCacheControlTime( $header, $private ) |
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| 171 | { |
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| 172 | 10 | $result = null; |
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| 173 | 10 | $dontcache = false; |
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| 174 | 10 | foreach ( $header as $value ) { |
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| 175 | 10 | if ( isset($value['value']) ) { |
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| 176 | 10 | switch($value['value']) { |
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| 177 | 10 | case 'private': |
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| 178 | 2 | if ( !$private ) { |
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| 179 | 2 | $dontcache = true; |
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| 180 | } |
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| 181 | 2 | break; |
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| 182 | 8 | case 'no-cache': |
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| 183 | 8 | case 'no-store': |
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| 184 | 8 | case 'must-revalidate': |
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| 185 | 8 | case 'proxy-revalidate': |
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| 186 | 2 | $dontcache = true; |
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| 187 | 10 | break; |
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| 188 | } |
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| 189 | 10 | } else if ( isset($value['max-age']) || isset($value['s-maxage']) ) { |
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| 190 | 10 | $maxage = (int) (isset($value['max-age']) ? $value['max-age'] : $value['s-maxage']); |
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| 191 | 10 | if ( isset($result) ) { |
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| 192 | 10 | $result = min($result, $maxage); |
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| 193 | } else { |
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| 194 | 10 | $result = $maxage; |
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| 195 | } |
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| 196 | } |
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| 197 | } |
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| 198 | 10 | if ( $dontcache ) { |
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| 199 | 4 | $result = 0; |
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| 200 | } |
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| 201 | 10 | return $result; |
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| 202 | } |
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| 203 | |||
| 204 | 2 | private static function orderByQuality($header) |
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| 205 | { |
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| 206 | $getQ = function($entry) { |
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| 207 | 2 | $q = ( isset($entry['q']) ? floatval($entry['q']) : 1); |
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| 208 | 2 | $name = $entry['value']; |
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| 209 | 2 | if ( $name[ strlen($name)-1 ] == '*' || $name[0] == '*' ) { |
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| 210 | 2 | $q -= 0.0001; // exact matches are preferred over wildcards |
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| 211 | } |
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| 212 | 2 | return $q; |
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| 213 | 2 | }; |
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| 214 | usort($header, function($a,$b) use ($getQ) { |
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| 215 | 2 | return ($getQ($a)>$getQ($b) ? -1 : 1); |
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| 216 | 2 | }); |
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| 217 | 2 | return $header; |
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| 218 | } |
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| 219 | |||
| 220 | 2 | private static function pregEscape($string) { |
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| 225 | |||
| 226 | 2 | private static function isAcceptable($name, $acceptable) |
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| 232 | |||
| 233 | /** |
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| 234 | * Return the last value sent for a specific header, uses the output of parse(). |
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| 235 | * @param (mixed) $headers An array with multiple header strings or a single string. |
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| 236 | * @return array|mixed |
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| 237 | */ |
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| 238 | 2 | private static function getLastHeader($headers) { |
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| 244 | |||
| 245 | |||
| 246 | } |
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