MQTT-KM (MQTT Kotlin Multiplatform)

A simple MQTT client kotlin multiplatform implementation.

WIKI will be available as soon as possible

Supported platforms and features

Platform	MQTT 3.1.1	TCP	TLS	Websocket
JVM	✅	✅	---	---
Windows X64	✅	✅	---	---
Linux X64	✅	✅	---	---
Linux ARM64	✅	✅	---	---
Linux ARM32	---	---	---	---
Node.js	---	---	---	---

Install

The library is available on Maven Central, so you can install with gradle by:

implementation("io.github.petretiandrea:mqtt-km:x.x.x") // kotlin dsl
implementation 'io.github.petretiandrea:mqtt-km:x.x.x' // groovy

Example

The mqtt library works by creating a safe event loop using coroutines. To build a valid client instance you need to provide a coroutine scope where launch a "background" coroutine event loop.

You can create a simple mqtt client instance by a special dsl provided by library.

fun main() = runBlocking { scope ->
    val client = mqtt(scope) {
        tcp { // also provide ssl, or websocket builder (actually not implemented)
            hostname = "broker.hivemq.com"
            port = 1883
            clientId = "client-1234"
        }

        // you can subscribe a lot of callbacks during creation...
        // onMessageReceive, onDisconnect, onDeliveryCompleted, etc...
        onSubscribeCompleted { subscribe, qoS ->
            println("Subscribe to: ${subscribe.topic} with qos: $qoS")
        }
    }
}

// ...or after
client.onMessageReceived { message -> println("$message")}

// connect returns a Result, which is a success when connection process ends successfully
client.connect()

// publish. This return a boolean, but the effective delivery of message is handled by event loop, so the message
// complete the delivery when onDeliveryCompleted is called.
val message = Message(MessageId.generate(), "topic/subtopic/", "data", QoS.Q1, retain = false, duplicate = false)
client.publish(message)


// disconnect
client.disconnect()