Live Telemetry via WebSocket

const WebSocket = require("ws");

// ── Configuration ───────────────────────────────────────────
const TB_URL = "https://thingsboard.cloud";   // ThingsBoard base URL
const WS_URL = "wss://thingsboard.cloud";    // use ws:// for plain HTTP
const USERNAME = "[email protected]";
const PASSWORD = "tenant";

// ── Step 1: Get JWT token via REST API ──────────────────────
async function getToken() {
  const res = await fetch(`${TB_URL}/api/auth/login`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ username: USERNAME, password: PASSWORD }),
  });
  if (!res.ok) throw new Error(`Login failed: ${res.status}`);
  const { token } = await res.json();
  return token;
}

// ── Name cache (updates carry only entityId, not fields) ────
const nameById = new Map();

// ── Step 2: Open WebSocket and subscribe ────────────────────
async function main() {
  const token = await getToken();
  console.log("Authenticated. Opening WebSocket...\n");

  const ws = new WebSocket(`${WS_URL}/api/ws`);

  ws.on("open", () => {
    // Authenticate + subscribe in one message
    const msg = {
      authCmd: { cmdId: 0, token },
      cmds: [
        {
          cmdId: 1,
          type: "ENTITY_DATA",
          query: {
            entityFilter: {
              type: "entityType",
              entityType: "DEVICE",
            },
            pageLink: {
              pageSize: 100,
              page: 0,
              sortOrder: {
                key: { type: "ENTITY_FIELD", key: "name" },
                direction: "ASC",
              },
            },
            entityFields: [
              { type: "ENTITY_FIELD", key: "name" },
              { type: "ENTITY_FIELD", key: "type" },
            ],
            latestValues: [
              { type: "TIME_SERIES", key: "temperature" },
              { type: "TIME_SERIES", key: "humidity" },
            ],
            keyFilters: [],
          },
          // Subscribe to real-time latest value updates
          latestCmd: {
            keys: [
              { type: "TIME_SERIES", key: "temperature" },
              { type: "TIME_SERIES", key: "humidity" },
            ],
          },
        },
      ],
    };
    ws.send(JSON.stringify(msg));
  });

  ws.on("message", (raw) => {
    const msg = JSON.parse(raw);

    if (msg.errorCode && msg.errorCode !== 0) {
      console.error("Error:", msg.errorMsg);
      return;
    }

    // Initial data response
    if (msg.data && msg.data.data) {
      console.log("=== Devices with latest telemetry ===\n");
      for (const entity of msg.data.data) {
        printEntity(entity);
      }
      console.log("\nListening for real-time updates... (Ctrl+C to stop)\n");
    }

    // Real-time update
    if (msg.update) {
      for (const entity of msg.update) {
        printEntity(entity);
      }
    }
  });

  ws.on("error", (err) => console.error("WebSocket error:", err.message));
  ws.on("close", () => console.log("WebSocket closed."));
}

// ── Helper: print entity telemetry ──────────────────────────
function printEntity(entity) {
  const id = entity.entityId.id;
  // Cache the name from the initial response; reuse on updates
  const fieldName = entity.latest?.ENTITY_FIELD?.name?.value;
  if (fieldName) nameById.set(id, fieldName);
  const name = nameById.get(id) ?? id;

  const temp = entity.latest?.TIME_SERIES?.temperature;
  const hum = entity.latest?.TIME_SERIES?.humidity;
  const parts = [`  ${name}:`];
  if (temp) parts.push(`temperature=${temp.value}`);
  if (hum) parts.push(`humidity=${hum.value}`);
  if (!temp && !hum) parts.push("(no telemetry yet)");
  console.log(parts.join(" "));
}

main().catch(console.error);