KMQTT
KMQTT is a Kotlin Multiplatform MQTT 3.1.1/5.0 Broker, with the objective of targeting the most possible build targets.
Features
| Platform | MQTT 3.1.1 | MQTT 5.0 | TCP | TLS | Websocket | Clustering |
|---|---|---|---|---|---|---|
| JVM | ||||||
| Windows X64 | ||||||
| Windows X86 | ||||||
| Linux X64 | ||||||
| Linux ARM32 | ||||||
| Linux ARM64 | ||||||
| Node.js |
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.