VK SDK Kotlin

Create a chat-bot for VK.com in a few lines of code, use the API and forget about the limitations

https://vk.com/vk_sdk

Unofficial VK.com SDK, written in Kotlin. Based on Kotlin Multiplatform project, but has Java-friendly API.

See the documentation: https://vksdk.github.io/vk-sdk-kotlin

Latest version:

For Kotlin 1.3.72 use version 0.0.5 and below.

Minimal example of the echo-chatbot

Kotlin

// From here: https://vk.com/club151083290 take the ID
val groupId = 151083290

// Read more: https://vk.com/dev/access_token
val accessToken = "abcdef123456..."

// There are two http clients available for now: 
// JVM-only OkHttp-based
// and common ktor-based
val vkHttpClient = VkOkHttpClient()

val client = VkApiClient(groupId, accessToken, VkApiClient.Type.Community, VkSettings(vkHttpClient))

client.onMessage { messageEvent ->
    client.sendMessage {
        peerId = messageEvent.message.peerId
        message = "Hello, World!"

        // You can use stickers, replies, location, etc.
        // All of the message parameters are supported.
    }.execute()
}

client.startLongPolling()

Java

int groupId = 151083290;
String accessToken = "abcdef123456...";
HttpClient vkHttpClient = new VkOkHttpClient();

VkApiClient client = new VkApiClient(groupId, accessToken, VkApiClient.Type.Community, new VkSettings(vkHttpClient));

client.onMessage(event -> {
    new Message()
        .peerId(event.getMessage().getPeerId())
        .text("Hello, world!")
        .sendFrom(client)
        .execute();
});

client.startLongPolling();

Features

The primary goal of the library is to cover most of the possible needs but in an abstract way. You can't find here a hundred of pre-defined data classes for each API method, but you can write the highly customizable solution in most convenient way.

• Supported platforms: JVM (+ Android), JS, darwin (iOS, macOS, tvOS, watchOS), mingwX64 (Windows), linuxX64
• Big and detailed examples: Multiplatform project (iOS & Android), Kotlin project, Java-only project. See the examples directory and the documentation.
• Written in Kotlin, but has JVM-friendly API with methods overloading, static methods, etc.
• Modularized and highly customizable: use pre-defined HTTP-clients or write your own; combine API calls, make queues or calls lists, etc.
• Use the client created from the code or from access_token.
• Bots Long Poll API
  • Event is a data class MessageNew for message_new event
  • and the JsonElement for all the other events
• Batch requests queue using execute method under the hood: make up to 75+ requests per second and don't think about the VK API limitations
  • Putting into batch requests queue is optional, but done by default for asynchronous requests
  • Synchronous calls always sent immediately
• API calls:
  • Synchronous
  • Asynchronous (using callbacks)
  • Using Kotlin Coroutines Flow wrapper
• messages.send: use DSL for sending messages and building keyboards. All method capabilities are covered.
  • Attach files in a couple of lines of code, using a file from disk, URL, etc.

Install

Library is uploaded to the Maven Central Repository.

For Gradle 6.0+ or with metadata enabled, add the dependencies in this way:

// core module is required
implementation "com.petersamokhin.vksdk:core:$vkSdkVersion"

// One of the HTTP clients is also required.
// You can use pre-defined OkHttp-based client, but only for JVM.
implementation "com.petersamokhin.vksdk:http-client-jvm-okhttp:$vkSdkVersion"

// Or else you can use the common HTTP client, which is based on ktor 
// and available for all of the platforms, including JVM.
// In this case, you also must specify the ktor engine.
implementation "com.petersamokhin.vksdk:http-client-common-ktor:$vkSdkVersion"

Otherwise, add enableFeaturePreview("GRADLE_METADATA") to settings.gradle or else you should specify the platform. Example for JVM:

implementation "com.petersamokhin.vksdk:core-jvm:$vkSdkVersion"
implementation "com.petersamokhin.vksdk:http-client-common-ktor-jvm:$vkSdkVersion"

// and OkHttp-based client is already JVM-only
implementation "com.petersamokhin.vksdk:http-client-jvm-okhttp:$vkSdkVersion"

Limitations

Unsupported platforms

• linuxArm32Hfp, linuxMips32
  • https://github.com/Kotlin/kotlinx.coroutines/issues/855

Unsupported functionality

• Attachment of a file (i.e. access to filesystem) is available only for JS, JVM and darwin. The other platform implementations may be in todo.
• Synchronous calls for js platform
  • https://github.com/Kotlin/kotlinx.coroutines/issues/195#issuecomment-354458878

3rd party

• Kotlin (coroutines, serialization, dokka)
• ktor client
• gradle-maven-publish-plugin
• OkHttp
• Stately
• SwiftUI for the iOS app in the multiplatform example

License

See the License