OAuth2 RPC (Kotlin)

This project is a Proof of Concept (PoC) that implements a small portion of the Discord OAuth2 flow and Rich Presence updates via the Discord Gateway WebSocket.

Usage

1. Add it to your root build.gradle at the end of repositories:

   allprojects {
       repositories {
           ...
           maven { url 'https://jitpack.io' }
       }
   }

2. Add the dependency (in your Java / Kotlin / Android project)

   dependencies {
      implementation("com.github.UsagiApp:OAuth2-RPC:$version")
   }

   Versions are available on JitPack

   When used in Android projects, core library desugaring with the NIO specification should be enabled to support Java 8+ features.

Project structure

The core library (in library/src/main/kotlin/com/discord/oauth2rpc/) provides:

Component	Description
Gateway.kt	Discord Gateway WebSocket client (Ktor + coroutines)
Rest.kt	REST API client with dynamic route builder
Interface.kt	TokenResponse, GatewayPacket, ReadyEvent, etc.
structures/Presence.kt	RichPresence, CustomStatus, SpotifyRPC builders
utils/	BitField, Intents, GatewayCapabilities, ActivityFlags, Constants, Util

Dependencies

• okhttp — HTTP & WebSocket
• org.json:json — JSON parsing
• kotlinx-coroutines — async concurrency

Setup

Prerequisites

• JDK 17+
• Gradle (or use the included wrapper)

Step 1: Create an Application

Go to the Discord Developer Portal and create a new Application.

Step 2: Unlock the Social SDK Feature

Fill out the Social SDK registration form (Games > Social SDK) to unlock this feature for your Application.

Step 3: Configure OAuth2

• Go to the newly created Application > Select the OAuth2 tab.
• Enable the "Public Client" setting.
• Add your Redirects URL to the list (usagi://discord-auth OR kotatsu://discord-auth), depends on your application.

Note

The bearer token remains valid for up to 7 days. You can use the refresh flow to renew its expiration and continue using the token.

Credits

• Original TS implementation by Elysia.
• Rewritten in Kotlin by Hà Tiến Sáng, modified by Draken.