void truncate(std::string& str, absl::optional<size_t> max_length) {

  if (!max_length) {

    return;

  }

  str = str.substr(0, max_length.value());

}

    : main_header_(main_header), alternative_header_(alternative_header), max_length_(max_length) {}

                                                    const StreamInfo::StreamInfo&) const {

  const Http::HeaderEntry* header = findHeader(context.requestHeaders());

  if (!header) {

    return absl::nullopt;

  }

  std::string val = Http::Utility::stripQueryString(header->value());

  truncate(val, max_length_);

  return val;

}

                                             const StreamInfo::StreamInfo&) const {

  const Http::HeaderEntry* header = findHeader(context.requestHeaders());

  if (!header) {

    return ValueUtil::nullValue();

  }

  std::string val = Http::Utility::stripQueryString(header->value());

  truncate(val, max_length_);

  return ValueUtil::stringValue(val);

}

const Http::HeaderEntry* ReqWithoutQuery::findHeader(OptRef<const Http::HeaderMap> headers) const {

  if (!headers.has_value()) {

    return nullptr;

  }

  const auto header = headers->get(main_header_);

  if (header.empty() && !alternative_header_.get().empty()) {

    const auto alternate_header = headers->get(alternative_header_);

    return alternate_header.empty() ? nullptr : alternate_header[0];

  }

  return header.empty() ? nullptr : header[0];

}

                                    absl::optional<size_t> max_length) const {

  if (command == "REQ_WITHOUT_QUERY") {

    auto status_or = Envoy::Formatter::SubstitutionFormatUtils::parseSubcommandHeaders(subcommand);

    THROW_IF_NOT_OK_REF(status_or.status());

    return std::make_unique<ReqWithoutQuery>(status_or.value().first, status_or.value().second,

                                             max_length);

  }

  return nullptr;

}