@pamoja/mqtt

An MQTT client with the topic and wildcard rules, as the core transport. One capability of pamoja, one memory-safe Rust core with bindings for TypeScript, Python, and C#.

Install

npm install @pamoja/mqtt

This pulls in @pamoja/native, the compiled engine. npm install pamoja is the whole framework in one package.

Example

The test that runs in CI, spliced here as it ran.

From bindings/node/guides/mqtt.ts:

import { MqttClient, Qos } from '@pamoja/mqtt'

// The broker on the site. The guide's CI runs one on localhost; point these at yours and
// nothing else changes.
const BROKER = '127.0.0.1'
const PORT = 1883

async function main(): Promise<{ topic: string; text?: string }> {
  // The gateway takes every temperature on the site. A `+` stands for exactly one level,
  // so this matches every node's temperature and nothing deeper.
  const gateway = new MqttClient({
    clientId: 'site-gateway',
    host: BROKER,
    port: PORT,
    qos: Qos.AtLeastOnce,
  })
  await gateway.connect()
  await gateway.subscribe('sensors/+/temperature')
  console.log('gateway   subscribed to sensors/+/temperature')

  // A node publishes under that pattern. At-least-once means the broker acknowledges the
  // message, so a node knows its reading was taken rather than hoping.
  const node = new MqttClient({
    clientId: 'node-1',
    host: BROKER,
    port: PORT,
    qos: Qos.AtLeastOnce,
  })
  await node.connect()
  await node.publish('sensors/1/temperature', '21.5')
  console.log('node      published 21.5 to sensors/1/temperature')

  // The gateway receives it with the topic attached, which is how it knows which node
  // sent the reading without the payload having to repeat it.
  const received = (await gateway.recv())!
  console.log(`gateway   got ${received.text!} on ${received.topic}`)

  // Disconnecting leaves the client reusable, so a node that loses its link can reconnect
  // the same object when the broker comes back.
  await node.disconnect()
  console.log(`node      disconnected, still connected: ${await node.isConnected()}`)
  await gateway.disconnect()

  // A broker that is not there is reported rather than leaving a client that looks
  // connected, so a retry loop has something to test.
  const nowhere = new MqttClient({ clientId: 'node-2', host: BROKER, port: 1, keepAliveSecs: 1 })
  try {
    await nowhere.connect()
    console.log('an unreachable broker accepted a connection, which should never happen')
  } catch (error) {
    console.log(`unreachable broker refused: ${(error as Error).message}`)
  }

  return received
}

main()

The same capability in every language

| Language | Package | Reference | | --- | --- | --- | | Rust | pamoja-mqtt | reference, docs.rs, install | | TypeScript | @pamoja/mqtt | reference, install | | Python | pamoja-mqtt | reference, install | | C# | Pamoja.Mqtt | reference, install |

Documentation

• @pamoja/mqtt reference, every class, function, and type this package exports.
• The MQTT guide, with the same example in Rust, Python, and C#.
• Every capability, and the install page.

License

MIT