Function refreshAccessToken

packages/oauth/src/oauth.ts:208–272

(
  config: OAuthFlowConfig,
  refreshToken: string,
  options: RefreshOptions,
)

}

export async function refreshAccessToken(
  config: OAuthFlowConfig,
  refreshToken: string,
  options: RefreshOptions,
): Promise<TokenInfo> {
  const maxRetries = options.maxRetries ?? 3;
  const backoff = options.backoffMs ?? ((attempt) => 2 ** attempt * 1000);
  const sleep =
    options.sleep ??
    ((ms: number) =>
      new Promise<void>((resolve) => {
        setTimeout(resolve, ms);
      }));
  const url = `${config.oauthHost.replace(/\/$/, '')}/api/oauth/token`;

  let lastError: Error | undefined;
  for (let attempt = 0; attempt < maxRetries; attempt += 1) {
    let status: number;
    let data: Record<string, unknown>;
    try {
      ({ status, data } = await postForm(
        url,
        {
          client_id: config.clientId,
          grant_type: 'refresh_token',
          refresh_token: refreshToken,
        },
        options.deviceHeaders,
      ));
    } catch (error) {
      // Transport-level failure (DNS, connection refused, timeout). Treat
      // as retryable to match Python's `aiohttp.ClientError` handling.
      lastError = error instanceof Error ? error : new OAuthError(String(error));
      if (attempt < maxRetries - 1) {
        await sleep(backoff(attempt));
        continue;
      }
      throw lastError instanceof Error ? lastError : new OAuthError(String(lastError));
    }

    if (status === 200 && typeof data['access_token'] === 'string') {
      return tokenFromResponse(data);
    }

    const errorCode = typeof data['error'] === 'string' ? data['error'] : '';
    const detail = extractApiErrorMessage(data);
    if (status === 401 || status === 403 || errorCode === 'invalid_grant') {
      throw new OAuthUnauthorizedError(detail ?? 'Token refresh unauthorized.');
    }

    const desc = detail ?? `Token refresh failed (HTTP ${status}).`;
    if (RETRYABLE_STATUSES.has(status)) {
      lastError = new RetryableRefreshError(desc);
      if (attempt < maxRetries - 1) {
        await sleep(backoff(attempt));
        continue;
      }
      // fall through: out of retries, surface the retryable error