Lightstreamer Kotlin Client Library

The Lightstreamer Kotlin Client Library enables any Kotlin/JVM application to communicate bidirectionally with a Lightstreamer Broker. This library allows you to subscribe to real-time data pushed by the server and send messages back to the server. It is written in Kotlin for the JVM, fully asynchronous, and optimized for performance.

⚠️ Note: This library is a lightweight, stripped-down version optimized for minimal resource usage.
For the fully featured and officially supported Lightstreamer client library for the JVM, please refer to the official project here.

Supported features:

• Lightstreamer Server 7.4 or later
• WS and WSS protocol
• Session recovery (a single attempt after failure)
• Heartbeat and reverse heartbeat
• Control-link
• All subscription modes
• Client messages
• TLCP-diff compression

Installation

The Lightstreamer Kotlin library requires JVM version 21 or later.

To add the library using Maven, include the following dependency:

<dependency>
  <groupId>com.lightstreamer</groupId>
  <artifactId>ls-kotlin-mini-client</artifactId>
  <version>0.2.0</version>
</dependency>

To add the library using Gradle, include:

dependencies {
  implementation('com.lightstreamer:ls-kotlin-mini-client:0.2.0')
}

Quickstart

To start a session with a Lightstreamer Server, you need to configure a LightstreamerClient.

Here's a minimal example demonstrating how to create a LightstreamerClient and connect to a Lightstreamer Server at https://push.lightstreamer.com:

import com.lightstreamer.kotlin.client.LightstreamerClient
import com.lightstreamer.kotlin.client.LightstreamerSession
import com.lightstreamer.kotlin.client.LightstreamerSubscription
import com.lightstreamer.kotlin.socket.LightstreamerServerAddress
import com.lightstreamer.kotlin.socket.SubscriptionMode
import com.lightstreamer.kotlin.socket.message.LightstreamerSubscriptionMessage
import kotlinx.coroutines.runBlocking

fun main() {
    runBlocking {
        // To connect to a Lightstreamer Server you need to configure a LightstreamerClient.
        // You can use the same client to open multiple sessions.
        // Close this client to terminate all generated sessions and release resources.
        val client = LightstreamerClient(
            serverAddress = LightstreamerServerAddress(
                host = "push.lightstreamer.com",
                port = 443u,
                secureConnection = true
            ),
            adapterSetName = "DEMO"
        )

        // Establish a new session
        val session: LightstreamerSession = client.openSession()
        // await connection and print session ID
        println("Lightstreamer Session ID ${session.sessionId.await()}")

        // Subscribe to a MERGE item
        val subscription: LightstreamerSubscription = session.subscribe(
            mode = SubscriptionMode.MERGE,
            dataAdapterName = "QUOTE_ADAPTER",
            itemGroup = "item1",
            itemFields = LightstreamerSubscription.FieldList("stock_name", "last_price"),
            requestSnapshot = true
        )

        // Consume subscription's events
        repeat(5) {
            val message: LightstreamerSubscriptionMessage = subscription.receive()
            println("Received: $message")
        }

        // Release resources
        client.close()
    }
}

Logging

This library uses SLF4j for logging.

Building the Library

To build the Lightstreamer Kotlin client, make sure you have SDKMAN! installed.

First, set up the dependencies defined in .sdkmanrc:

sdk env install

Then build and test using Gradle:

gradle build

Publish library on Maven Central

This library is published in the Maven Central Repository. To release a new version, you need the signature key and Sonatype's Access Token.

export SONATYPE_TOKEN=...
export SONATYPE_TOKEN_PASSWORD='...'
gradle publish

Then access to staging repository, close and publish it.

Documentation

• API reference

Support

For questions and support, please visit the official Lightstreamer forum. Please note that the issue tracker on this page is intended exclusively for reporting bugs and submitting feature requests.