KMQTT

Embeddable and standalone Kotlin Multiplatform MQTT broker

Programming language: Kotlin

License: MIT License

Tags: Multiplatform    

Latest version: v0.2.3

README

KMQTT

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

Features

:x: = To Do
:white_check_mark: = Supported
:heavy_plus_sign: = Work In Progress

Platform	MQTT 3.1.1	MQTT 5.0	TCP	TLS	Websocket	Clustering
JVM	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:heavy_plus_sign:
Windows X64	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:x:
Windows X86	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:x:
Linux X64	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:x:
Linux ARM32	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:x:
Linux ARM64	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:x:
Node.js	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:x:

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
--wsp	null	The WebSocket port to listen to

Library

Gradle Maven

Global dependencies

repositories {
    jcenter()
    maven { url "https://jitpack.io" }
}
dependencies {
    implementation 'com.github.davidepianca98.KMQTT:kmqtt-jvm:0.3.2'
}

Replace jvm with js, linuxx64, linuxarm64, linuxarm32hfp, mingwx64, mingwx86 based on the desired target.

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:kmqtt:0.3.2'
            }
        }
    }
}

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(clientId: String, username: String?, password: UByteArray?): Boolean {
            // TODO Implement your authentication method    
            return username == "user" && password?.toByteArray()?.decodeToString() == "pass"
        }
    })
    broker.listen()
}

Authorization code example

fun main() {
    val broker = Broker(authorization = object : Authorization {
        override fun authorize(
            clientId: String,
            username: String?,
            password: UByteArray?, // != null only if savePassword set to true in the broker constructor
            topicName: String,
            isSubscription: Boolean,
            payload: UByteArray?
        ): Boolean {
            // TODO Implement your authorization method    
            return topicName == "$clientId/topic"
        }
    })
    broker.listen()
}

Message interceptor code example

fun main() {
    val broker = Broker(packetInterceptor = object : PacketInterceptor {
        override fun packetReceived(clientId: String, username: String?, password: UByteArray?, 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()
}

Other advanced functionality

MQTT5 Enhanced Authentication: set the enhancedAuthenticationProviders Broker constructor parameter, implementing the provider interface EnhancedAuthenticationProvider.

Session persistence: set the persistence Broker constructor parameter, implementing Persistence interface.

Bytes metrics: set the bytesMetrics Broker constructor parameter, implementing BytesMetrics interface.