includes/libs/http/HttpAcceptParser.php

   1 <?php
   2
   3 /**
   4  * Utility for parsing a HTTP Accept header value into a weight map. May also be used with
   5  * other, similar headers like Accept-Language, Accept-Encoding, etc.
   6  *
   7  * @license GPL-2.0-or-later
   8  * @author Daniel Kinzler
   9  */
  10
  11 namespace Wikimedia\Http;
  12
  13 class HttpAcceptParser {
  14
  15         /**
  16          * Parses an HTTP header into a weight map, that is an associative array
  17          * mapping values to their respective weights. Any header name preceding
  18          * weight spec is ignored for convenience.
  19          *
  20          * This implementation is partially based on the code at
  21          * http://www.thefutureoftheweb.com/blog/use-accept-language-header
  22          *
  23          * Note that type parameters and accept extension like the "level" parameter
  24          * are not supported, weights are derived from "q" values only.
  25          *
  26          * @todo If additional type parameters are present, ignore them cleanly.
  27          *        At present, they often confuse the result.
  28          *
  29          * See HTTP/1.1 section 14 for details.
  30          *
  31          * @param string $rawHeader
  32          *
  33          * @return array
  34          */
  35         public function parseWeights( $rawHeader ) {
  36                 //FIXME: The code below was copied and adapted from WebRequest::getAcceptLang.
  37                 //       Move this utility class into core for reuse!
  38
  39                 // first, strip header name
  40                 $rawHeader = preg_replace( '/^[-\w]+:\s*/', '', $rawHeader );
  41
  42                 // Return values in lower case
  43                 $rawHeader = strtolower( $rawHeader );
  44
  45                 // Break up string into pieces (values and q factors)
  46                 $value_parse = null;
  47                 preg_match_all( '@([a-z\d*]+([-+/.][a-z\d*]+)*)\s*(;\s*q\s*=\s*(1(\.0{0,3})?|0(\.\d{0,3})?)?)?@',
  48                         $rawHeader, $value_parse );
  49
  50                 if ( !count( $value_parse[1] ) ) {
  51                         return [];
  52                 }
  53
  54                 $values = $value_parse[1];
  55                 $qvalues = $value_parse[4];
  56                 $indices = range( 0, count( $value_parse[1] ) - 1 );
  57
  58                 // Set default q factor to 1
  59                 foreach ( $indices as $index ) {
  60                         if ( $qvalues[$index] === '' ) {
  61                                 $qvalues[$index] = 1;
  62                         } elseif ( $qvalues[$index] == 0 ) {
  63                                 unset( $values[$index], $qvalues[$index], $indices[$index] );
  64                         } else {
  65                                 $qvalues[$index] = (float)$qvalues[$index];
  66                         }
  67                 }
  68
  69                 // Sort list. First by $qvalues, then by order. Reorder $values the same way
  70                 array_multisort( $qvalues, SORT_DESC, SORT_NUMERIC, $indices, $values );
  71
  72                 // Create a list like "en" => 0.8
  73                 $weights = array_combine( $values, $qvalues );
  74
  75                 return $weights;
  76         }
  77
  78 }