Function fetchDeviceId

apps/api/src/controllers/track.controller.ts:458–539

(
  request: FastifyRequest,
  reply: FastifyReply
)

}

export async function fetchDeviceId(
  request: FastifyRequest,
  reply: FastifyReply
) {
  const salts = await getSalts();
  const projectId = request.client?.projectId;
  if (!projectId) {
    return reply.status(400).send('No projectId');
  }

  const ip = request.clientIp;
  if (!ip) {
    return reply.status(400).send('Missing ip address');
  }

  const ua = request.headers['user-agent'];
  if (!ua) {
    return reply.status(400).send('Missing header: user-agent');
  }

  const currentDeviceId = generateDeviceId({
    salt: salts.current,
    origin: projectId,
    ip,
    ua,
  });
  const previousDeviceId = generateDeviceId({
    salt: salts.previous,
    origin: projectId,
    ip,
    ua,
  });

  try {
    const [current, previous] = await Promise.all([
      sessionBuffer.getExistingSession({
        projectId,
        deviceId: currentDeviceId,
      }),
      sessionBuffer.getExistingSession({
        projectId,
        deviceId: previousDeviceId,
      }),
    ]);

    // Blob has no TTL — only treat the session as "current" if its last
    // event is within the idle window. Otherwise the SDK should ask the
    // server to start a fresh session id on the next event.
    const now = Date.now();
    const isLive = (s: typeof current) =>
      !!s &&
      now - convertClickhouseDateToJs(s.ended_at).getTime() <
        SESSION_TIMEOUT_MS;

    if (current && isLive(current)) {
      return reply.status(200).send({
        deviceId: currentDeviceId,
        sessionId: current.id,