throwForHttpStatus function

Never throwForHttpStatus(int statusCode, String body, String providerName)

Checks an HTTP status code and throws typed exceptions for known errors.

Call this in providers before the generic throw Exception(...) fallback.

Implementation

Never throwForHttpStatus(int statusCode, String body, String providerName) {
  if (statusCode == 401 || statusCode == 403) {
    throw AuthenticationException(
      '$providerName: Invalid or expired API key (HTTP $statusCode).',
    );
  }
  if (statusCode == 429) {
    // Try to parse Retry-After header value from the body (some providers
    // include it). Fall back to a default backoff.
    throw RateLimitException(
      '$providerName: Rate limited (HTTP 429). Slow down.',
    );
  }
  // Token/context overflow typically returns 400 with a specific message.
  final lowerBody = body.toLowerCase();
  if (statusCode == 400 &&
      (lowerBody.contains('context') ||
          lowerBody.contains('token') ||
          lowerBody.contains('too long') ||
          lowerBody.contains('maximum'))) {
    throw ContextOverflowException(
      '$providerName: Conversation too long for model context window.',
    );
  }
  if (statusCode == 529) {
    throw RateLimitException(
      '$providerName: API overloaded (HTTP $statusCode). Retry shortly.',
    );
  }
  // Server errors (5xx) — retryable.
  if (statusCode >= 500) {
    throw RateLimitException(
      '$providerName: Server error (HTTP $statusCode). Retry shortly.',
    );
  }
  throw Exception('$providerName API error (HTTP $statusCode): $body');
}