HttpAcceptParser.php

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<?php

namespace Wikimedia\Http;

class HttpAcceptParser {

    public function parseAccept( $accept ): array {
        $accepts = explode( ',', $accept );  // FIXME: Allow commas in quotes
        $ret = [];

        foreach ( $accepts as $i => $a ) {
            preg_match( '!^([^\s/;]+)/([^;\s]+)\s*(?:;(.*))?$!D', trim( $a ), $matches );
            if ( !$matches ) {
                continue;
            }
            $q = 1;
            $params = [];
            if ( isset( $matches[3] ) ) {
                $kvps = explode( ';', $matches[3] );  // FIXME: Allow semi-colon in quotes
                foreach ( $kvps as $kv ) {
                    [ $key, $val ] = explode( '=', trim( $kv ), 2 );
                    $key = strtolower( trim( $key ) );
                    $val = trim( $val );
                    if ( $key === 'q' ) {
                        $q = (float)$val;  // FIXME: Spec is stricter about this
                    } else {
                        if ( $val && $val[0] === '"' && $val[ strlen( $val ) - 1 ] === '"' ) {
                            $val = substr( $val, 1, strlen( $val ) - 2 );
                        }
                        $params[$key] = $val;
                    }
                }
            }
            $ret[] = [
                'type' => $matches[1],
                'subtype' => $matches[2],
                'q' => $q,
                'i' => $i,
                'params' => $params,
            ];
        }

        // Sort list. First by q values, then by order
        usort( $ret, function ( $a, $b ) {
            if ( $b['q'] > $a['q'] ) {
                return 1;
            } elseif ( $b['q'] === $a['q'] ) {
                return $a['i'] - $b['i'];
            } else {
                return -1;
            }
        } );

        return $ret;
    }

    public function parseWeights( $rawHeader ) {
        // first, strip header name
        $rawHeader = preg_replace( '/^[-\w]+:\s*/', '', $rawHeader );

        // Return values in lower case
        $rawHeader = strtolower( $rawHeader );

        $accepts = $this->parseAccept( $rawHeader );

        // Create a list like "en" => 0.8
        return array_reduce( $accepts, function ( $prev, $next ) {
            $type = "{$next['type']}/{$next['subtype']}";
            $prev[$type] = $next['q'];
            return $prev;
        }, [] );
    }

}