KMQTT

KMQTT is a Kotlin Multiplatform MQTT 3.1.1/5.0 Broker, with the objective of targeting the most possible build targets.

Features

✖️ = TODO ✔️ = Supported ➕ = Experimental

Platform	MQTT 3.1.1	MQTT 5.0	Clustering	TCP	TLS	UDP	Websocket
JVM	✔️	✔️	➕	✔️	✔️	➕	✖️
Windows X64	✔️	✔️	➕	✔️	✔️	➕	✖️
Linux X64	✔️	✔️	➕	✔️	✔️	➕	✖️
Linux ARM32	✔️	✔️	➕	✔️	✔️	➕	✖️

Getting Started

Executables

You can download the executables for your platform under the release tab

Program Arguments

Argument	Default Value	Description
-h	127.0.0.1	Interface address to bind the server to
-p	1883	Server port to listen to
--max-connections	128	The maximum number of TCP connections to support
--key-store	null	The path to the PKCS12 keystore containing the private key and the certificate for TLS, if null TLS is disabled
--key-store-psw	null	The password of the PKCS12 keystore indicated in --key-store, if the keystore has no password set, don't set the option

Library

Gradle Maven

Global dependencies

repositories {
    jcenter()
    maven { url "https://jitpack.io" }
}
dependencies {
    implementation 'com.github.davidepianca98:KMQTT:0.2.3'
}

Kotlin Multiplatform plugin

On the Kotlin Multiplatform plugin you only need to require the dependency on the common source set and the platform specific parts will automatically be required

repositories {
    jcenter()
    maven { url "https://jitpack.io" }
}

kotlin {
    jvm()
    mingwX64("mingw")
    sourceSets {
        commonMain {
            dependencies {
                implementation 'com.github.davidepianca98:KMQTT:0.2.3'
            }
        }
    }
}

Quick start code example

This code starts the MQTT broker on port 1883 without TLS encryption. You can play with Broker() constructor parameters to set the various settings

fun main() {
    Broker().listen()
}

TLS code example

The keystore must be in PKCS12 format, the keystore password can be null

fun main() {
    val broker = Broker(
        tlsSettings = TLSSettings(keyStoreFilePath = "keyStore.p12", keyStorePassword = "password"),
        port = 8883
    ).listen()
    broker.listen()
}

Authentication code example

fun main() {
    val broker = Broker(authentication = object : Authentication {
        override fun authenticate(username: String?, password: UByteArray?): Boolean {
            // TODO Implement your authentication method    
            return username == "user" && password?.toByteArray()?.decodeToString() == "pass"
        }
    })
    broker.listen()
}

Message interceptor code example

fun main() {
    val broker = Broker(packetInterceptor = object : PacketInterceptor {
        override fun packetReceived(packet: MQTTPacket) {
            when(packet) {
                is MQTTConnect -> println(packet.protocolName)
                is MQTTPublish -> println(packet.topicName)
            }
        }
    })
    broker.listen()
}

Internal publish code example

fun main() {
    val broker = Broker()
    broker.publish(
        retain = false,
        topicName = "test/",
        qos = Qos.AT_MOST_ONCE,
        properties = MQTTProperties(),
        "testPayload".toByteArray().toUByteArray()
    )
    broker.listen()
}