Parser.php

<?php

declare (strict_types=1);
namespace OpenTelemetry\API\Baggage\Propagation;

use function explode;
use OpenTelemetry\API\Baggage\BaggageBuilderInterface;
use OpenTelemetry\API\Baggage\Metadata;
use function str_replace;
use function trim;
use function urldecode;
final class Parser {
    private const EXCLUDED_KEY_CHARS = [
        ' ',
        '(',
        ')',
        '<',
        '>',
        '@',
        ',',
        ';',
        ':',
        '\\',
        '"',
        '/',
        '[',
        ']',
        '?',
        '=',
        '{',
        '}',
    ];
    private const EXCLUDED_VALUE_CHARS = [
        ' ',
        '"',
        ',',
        ';',
        '\\',
    ];
    private const EQUALS = '=';
    public function __construct(string $baggageHeader) {
    }
    public function parseInto(BaggageBuilderInterface $baggageBuilder) : void {
        foreach (explode(',', $this->baggageHeader) as $baggageString) {
            if (empty(trim($baggageString))) {
                continue;
            }
            $explodedString = explode(';', $baggageString, 2);
            $keyValue = trim($explodedString[0]);
            if (empty($keyValue) || mb_strpos($keyValue, self::EQUALS) === false) {
                continue;
            }
            $metadataString = $explodedString[1] ?? null;
            if ($metadataString && !empty(trim($metadataString))) {
                $metadata = new Metadata(trim($metadataString));
            }
            else {
                $metadata = null;
            }
            
            /** @psalm-suppress PossiblyUndefinedArrayOffset */
            [
                $key,
                $value,
            ] = explode(self::EQUALS, $keyValue, 2);
            $key = urldecode($key);
            $value = urldecode($value);
            $key = str_replace(self::EXCLUDED_KEY_CHARS, '', trim($key), $invalidKeyCharacters);
            if (empty($key) || $invalidKeyCharacters > 0) {
                continue;
            }
            $value = str_replace(self::EXCLUDED_VALUE_CHARS, '', trim($value), $invalidValueCharacters);
            if (empty($value) || $invalidValueCharacters > 0) {
                continue;
            }
            $baggageBuilder->set($key, $value, $metadata);
        }
    }

}