IoT and MQTT#

Tina4 includes a zero-dependency MQTT 3.1.1 client for telemetry, device state, asset tracking, and EV charging. It connects to an external broker such as Mosquitto, EMQX, HiveMQ, or AWS IoT. Tina4 is not a broker.

Configure, connect, and publish#

TINA4_MQTT_URL=mqtt://127.0.0.1:1883TINA4_MQTT_CLIENT_ID=warehouse-apiTINA4_MQTT_KEEPALIVE=60TINA4_MQTT_TLS_VERIFY=trueTINA4_MQTT_CA_FILE=/run/secrets/mqtt-ca.pem

Use mqtt:// or tcp:// for plain TCP and mqtts:// for TLS. Put credentials in URL user information or constructor options. There are no username or password environment variables.

import { Mqtt } from "tina4-nodejs";​const mqtt = new Mqtt();await mqtt.connect();const packetId = await mqtt.publish(  "fleet/meter-42/telemetry",  JSON.stringify({ kwh: 12.5 }),  1,);await mqtt.disconnect();

Node.js connects explicitly. QoS 0 waits for no acknowledgement. QoS 1 returns the packet id after PUBACK. Tina4 refuses QoS 2.

const mqtt = new Mqtt({ cleanSession: false });await mqtt.connect();​for await (const message of mqtt.consume("fleet/+/telemetry", 1)) {  process(message.topic, message.text());}

consume() acknowledges after successful loop handling. Use receive(undefined, false) followed by message.acknowledge() for manual control. Messages expose topic, byte payload, QoS, packet id, retained and duplicate flags, acknowledgement, text(), and toObject().

Retained publishes store current state; an empty retained payload clears it. Configure willTopic, willPayload, willQos, and willRetain for an unclean disconnect. disconnect() suppresses the will; kill() lets the broker publish it. TLS verification defaults to true. tls(), cipher(), and tlsVersion() report the connection. One client has one socket reader.