Message Translator Discord Bot

A Discord bot that translates messages using Google's Gemini AI. Supports both context menu commands and slash commands for easy message translation.

Features

• 🌍 Context Menu Translation: Right-click any message to translate it
• ⌨️ Slash Command: Use /translate to translate custom text
• 🤖 Powered by Gemini AI: Advanced language detection and translation
• 🐳 Docker Ready: Easy deployment with Docker and Docker Compose
• 🔒 Secure: Input sanitization and proper error handling
• ✅ Health Checks: Built-in health monitoring for container orchestration

Prerequisites

• Bun runtime (v1.0 or higher)
• Discord Bot Application (Create one here)
• Google Gemini API Key (Get one here)
• Docker and Docker Compose (for containerized deployment)

Setup

1. Clone the Repository

git clone <your-repo-url>
cd message_translator

2. Install Dependencies

bun install

3. Configure Environment Variables

Copy the example environment file:

cp .env.example .env

Edit .env and fill in your credentials:

# Discord Bot Configuration
APP_ID=your_discord_app_id
DISCORD_TOKEN=your_discord_bot_token
PUBLIC_KEY=your_discord_public_key

# Optional: For instant testing in a specific guild
DEV_GUILD_ID=your_development_guild_id

# Google AI Configuration
GEMINI_API_KEY=your_google_genai_api_key

Getting Discord Credentials

1. Go to Discord Developer Portal
2. Create a new application or select an existing one
3. Go to the "Bot" section to get your DISCORD_TOKEN
4. Go to "General Information" to get your APP_ID and PUBLIC_KEY
5. Enable the "Message Content Intent" in the Bot settings

Getting Google Gemini API Key

1. Visit Google AI Studio
2. Sign in with your Google account
3. Create a new API key
4. Copy the key to your .env file

4. Register Discord Commands

The bot automatically registers commands on startup. Commands include:

• Translate Message (Context Menu): Right-click on any message
• /translate (Slash Command): Translate custom text

Commands are registered globally and may take up to 1 hour to propagate. If you set DEV_GUILD_ID, they'll also be registered instantly in that specific guild for testing.

Running the Bot

Local Development

# Run with auto-reload
bun run dev

# Or run normally
bun run start

The server will start on http://0.0.0.0:3000

Docker Deployment

Using Docker Compose (Recommended)

# Build and start the container
docker-compose up -d

# View logs
docker-compose logs -f

# Stop the container
docker-compose down

Using Docker Directly

# Build the image
docker build -t message-translator .

# Run the container
docker run -d \
  --name message-translator \
  -p 3000:3000 \
  --env-file .env \
  message-translator

Discord Bot Configuration

Setting the Interactions Endpoint URL

1. Go to your application in the Discord Developer Portal
2. Navigate to "General Information"
3. Set the "Interactions Endpoint URL" to your public URL (e.g., https://your-domain.com)
4. Discord will send a POST request to verify the endpoint

Important: Your bot must be publicly accessible for Discord to send interactions. Consider using:

• A VPS or cloud hosting service
• ngrok for local development testing
• Reverse proxy (nginx, Caddy) for production

Bot Permissions

When inviting the bot to your server, ensure it has:

• applications.commands scope
• No special permissions required (bot responds with ephemeral messages)

Invite URL format:

https://discord.com/api/oauth2/authorize?client_id=YOUR_APP_ID&scope=applications.commands

Usage

Context Menu Command

1. Right-click (or long-press on mobile) any message
2. Select "Apps" → "Translate Message"
3. The bot will detect the language and translate it to English

Slash Command

/translate message:"Hello, how are you?" language:"spanish"

The bot will translate the provided text to the specified language.

Project Structure

message_translator/
├── src/
│   ├── index.ts       # Main server and Discord interaction handler
│   ├── gemini.ts      # Google Gemini AI translation logic
│   └── register.ts    # Discord command registration
├── .github/
│   └── workflows/
│       └── docker-build.yml  # CI/CD for building Docker images
├── Dockerfile         # Multi-stage Docker build
├── docker-compose.yml # Docker Compose configuration
├── package.json       # Dependencies and scripts
├── tsconfig.json      # TypeScript configuration
├── .env.example       # Environment variable template
└── README.md         # This file

Health Check

The bot includes a health check endpoint at /health that returns:

{
  "status": "ok",
  "timestamp": "2025-12-15T10:30:00.000Z"
}

This is used by Docker's health check system to monitor the container.

Security Features

• ✅ Discord signature verification for all incoming requests
• ✅ Input sanitization to prevent prompt injection attacks
• ✅ Character limits on user inputs (2000 chars for messages, 50 for language)
• ✅ Environment variable validation on startup
• ✅ Proper error handling with user-friendly error messages

Troubleshooting

Commands not showing up in Discord

• Wait up to 1 hour for global commands to propagate
• Use DEV_GUILD_ID for instant testing in a specific server
• Check bot logs for registration errors

"Invalid request signature" errors

• Verify your PUBLIC_KEY is correct in .env
• Ensure your public URL is correctly set in Discord Developer Portal

Translation failures

• Check that GEMINI_API_KEY is valid
• Verify you haven't exceeded Google AI API quotas
• Check container logs: docker-compose logs -f

Container health check failing

• Ensure port 3000 is accessible
• Check if curl is available in the container
• View health status: docker inspect message-translator

GitHub Actions CI/CD

This project includes a GitHub Actions workflow that:

• Builds multi-platform Docker images (linux/amd64, linux/arm64)
• Pushes to GitHub Container Registry (ghcr.io)
• Runs on pushes to main/master and on tags
• Creates build attestations for supply chain security

To use it:

1. Enable GitHub Actions in your repository
2. Ensure GitHub Packages write permissions are enabled
3. Push to main branch or create a version tag (e.g., v1.0.0)

Images are available at: ghcr.io/<username>/message_translator:latest

Development

Running Tests

# No tests configured yet
# Add your test commands here

Code Style

The project uses TypeScript with strict mode enabled. Run type checking:

bun run tsc --noEmit

Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is open source. Add your preferred license here.

Support

For issues and questions:

• Open an issue on GitHub
• Check the Discord Developer Documentation
• Review Google Gemini API Documentation

Acknowledgments

• Built with Bun
• Powered by Google Gemini AI
• Discord integration via discord.js