Function errorResponse

packages/server/src/http/error-response.ts:59–187

(
  res: ServerResponse,
  status: HttpErrorStatus,
  type: ProblemType,
  title: string,
  options: ErrorResponseOptions = {},
)

>;

export function errorResponse(
  res: ServerResponse,
  status: HttpErrorStatus,
  type: ProblemType,
  title: string,
  options: ErrorResponseOptions = {},
): void {
  const instance = options.instance ?? `urn:uuid:${randomUUID()}`;

  if (res.headersSent || res.writableEnded || res.destroyed) {
    log().error(
      {
        event: 'api.error.double-write',
        instance,
        type,
        status,
        handler: options.handler,
      },
      'errorResponse called after headers already sent — suppressed',
    );
    apiErrorCounter().add(1, {
      type: 'urn:ok:error:internal-server-error',
      ...(options.handler ? { handler: options.handler } : {}),
    });
    return;
  }

  const body: ProblemDetails = {
    type,
    title,
    status,
    instance,
    detail: options.detail ?? undefined,
  };
  const validated = ProblemDetailsSchema.safeParse(body);
  if (!validated.success) {
    log().error(
      {
        event: 'api.error.malformed-envelope',
        issues: validated.error.issues,
        body,
        handler: options.handler,
        originalStatus: status,
      },
      'errorResponse produced an invalid ProblemDetails body — emitting fallback',
    );
    const fallbackStatus = 500 as const;
    apiErrorCounter().add(1, {
      type: 'urn:ok:error:internal-server-error',
      ...(options.handler ? { handler: options.handler } : {}),
    });
    res.writeHead(fallbackStatus, {
      'Content-Type': 'application/problem+json',
      'X-Content-Type-Options': 'nosniff',
    });
    res.end(
      JSON.stringify({
        type: 'urn:ok:error:internal-server-error' satisfies ProblemType,