---
title: Development Guide
description: Build, test, and contribute to DropOut
---

# Development Guide

This guide will help you set up a development environment, build DropOut from source, and contribute to the project.

## Prerequisites

### Required Software

1. **Rust** (latest stable)
   ```bash
   # Install via rustup
   curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
   ```

2. **Node.js** (v22+) and **pnpm** (v9+)
   ```bash
   # Install Node.js from https://nodejs.org/
   # Install pnpm
   npm install -g pnpm@9
   ```

3. **System Dependencies**

   Follow the [Tauri Prerequisites](https://v2.tauri.app/start/prerequisites/) for your platform:

   **Linux (Debian/Ubuntu):**
   ```bash
   sudo apt update
   sudo apt install libwebkit2gtk-4.1-dev \
     build-essential \
     curl \
     wget \
     file \
     libssl-dev \
     libayatana-appindicator3-dev \
     librsvg2-dev
   ```

   **macOS:**
   ```bash
   xcode-select --install
   ```

   **Windows:**
   - Install [Microsoft Visual C++ Build Tools](https://visualstudio.microsoft.com/visual-cpp-build-tools/)
   - Install [WebView2](https://developer.microsoft.com/microsoft-edge/webview2/)

## Getting Started

### Clone the Repository

```bash
git clone https://github.com/HydroRoll-Team/DropOut.git
cd DropOut
```

### Install Dependencies

**Frontend dependencies:**
```bash
cd packages/ui
pnpm install
cd ../..
```

**Documentation dependencies:**
```bash
cd packages/docs
pnpm install
cd ../..
```

### Development Mode

Run DropOut in development mode with hot reload:

```bash
cargo tauri dev
```

This will:
1. Start the frontend dev server (Vite on port 5173)
2. Compile the Rust backend
3. Open the Tauri window
4. Enable hot reload for frontend changes
5. Recompile on Rust file changes

**Terminal output:**
- Frontend logs from Vite
- Rust stdout/stderr
- Compilation status

### Building for Production

Build release binaries:

```bash
cargo tauri build
```

**Output locations:**
- **Linux**: `src-tauri/target/release/bundle/`
  - `.deb` package
  - `.AppImage` bundle
- **macOS**: `src-tauri/target/release/bundle/`
  - `.dmg` installer
  - `.app` bundle
- **Windows**: `src-tauri/target/release/bundle/`
  - `.msi` installer
  - `.exe` executable

## Project Structure

```
DropOut/
├── src-tauri/              # Rust backend
│   ├── src/
│   │   ├── main.rs         # Tauri commands & entry point
│   │   ├── core/           # Core modules
│   │   │   ├── auth.rs     # Authentication
│   │   │   ├── downloader.rs # Download manager
│   │   │   ├── fabric.rs   # Fabric support
│   │   │   ├── forge.rs    # Forge support
│   │   │   ├── java.rs     # Java management
│   │   │   ├── instance.rs # Instance system
│   │   │   └── ...
│   │   └── utils/          # Utilities
│   └── Cargo.toml
├── packages/
│   ├── ui/                 # Svelte 5 frontend
│   │   ├── src/
│   │   │   ├── App.svelte
│   │   │   ├── components/
│   │   │   ├── stores/     # State management
│   │   │   └── lib/
│   │   └── package.json
│   └── docs/               # Documentation site
│       ├── content/docs/
│       └── package.json
├── .github/
│   └── workflows/          # CI/CD pipelines
└── scripts/                # Build scripts
```

## Development Workflows

### Frontend Development

**Start dev server:**
```bash
cd packages/ui
pnpm dev
```

**Type checking:**
```bash
pnpm check
```

**Linting:**
```bash
pnpm lint
```

**Formatting:**
```bash
pnpm format
```

### Backend Development

**Run Rust tests:**
```bash
cargo test
```

**Check code:**
```bash
cargo check
```

**Format code:**
```bash
cargo fmt
```

**Lint code:**
```bash
cargo clippy
```

### Documentation Development

**Start docs dev server:**
```bash
cd packages/docs
pnpm dev
```

**Build docs:**
```bash
pnpm build
```

**Type check:**
```bash
pnpm types:check
```

## Code Style

### Rust

Follow standard Rust conventions:
- Use `cargo fmt` for formatting
- Use `cargo clippy` for linting
- Write documentation comments (`///`)
- Handle errors properly
- Use async/await for I/O

**Example:**
```rust
/// Starts the Microsoft authentication device flow
#[tauri::command]
async fn start_microsoft_login(
    window: Window,
) -> Result<DeviceCodeResponse, String> {
    emit_log!(window, "Starting Microsoft login...");
    
    start_device_flow()
        .await
        .map_err(|e| e.to_string())
}
```

### TypeScript/Svelte

Follow the project's conventions:
- Use Svelte 5 runes (`$state`, `$effect`)
- Prefer TypeScript over JavaScript
- Use Biome for formatting and linting
- Follow component structure

**Example:**
```typescript
// stores/auth.svelte.ts
export class AuthState {
  currentAccount = $state<Account | null>(null);
  isLoginModalOpen = $state(false);
  
  async login(username: string) {
    const account = await invoke('offline_login', { username });
    this.currentAccount = account;
  }
}
```

## Testing

### Unit Tests

**Rust:**
```rust
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_generate_offline_uuid() {
        let uuid = generate_offline_uuid("Player");
        assert!(uuid.len() > 0);
    }
}
```

**Run:**
```bash
cargo test
```

### Integration Tests

Test the full application:
1. Build in dev mode: `cargo tauri dev`
2. Manually test features
3. Check console for errors
4. Verify UI behavior

### CI Tests

GitHub Actions runs tests on:
- Ubuntu (latest)
- Arch Linux (Wayland)
- Windows (latest)
- macOS (ARM64)

View workflow: `.github/workflows/test.yml`

## Debugging

### Frontend Debugging

1. Open DevTools in Tauri window: `Ctrl+Shift+I` (Windows/Linux) or `Cmd+Option+I` (macOS)
2. Check Console for errors
3. Use React DevTools or Svelte DevTools
4. Monitor Network tab for API calls

### Backend Debugging

**Print debugging:**
```rust
emit_log!(window, format!("Debug: {}", value));
println!("Debug: {}", value);
```

**Rust debugger:**
```bash
# Install rust-lldb or rust-gdb
cargo install rust-gdb

# Debug
rust-gdb target/debug/dropout
```

### Logging

**Frontend:**
```typescript
console.log("Info message");
console.error("Error message");
```

**Backend:**
```rust
emit_log!(window, "Status update");
eprintln!("Error: {}", error);
```

## Contributing

### Contribution Workflow

1. **Fork** the repository
2. **Create** a feature branch:
   ```bash
   git checkout -b feature/my-feature
   ```
3. **Make** your changes
4. **Test** thoroughly
5. **Commit** with conventional commits:
   ```bash
   git commit -m "feat: add new feature"
   ```
6. **Push** to your fork:
   ```bash
   git push origin feature/my-feature
   ```
7. **Create** a pull request

### Commit Messages

Follow [Conventional Commits](https://www.conventionalcommits.org/):

**Format:**
```
<type>[scope]: <description>

[optional body]

[optional footer]
```

**Types:**
- `feat`: New feature
- `fix`: Bug fix
- `docs`: Documentation
- `style`: Formatting
- `refactor`: Code restructuring
- `perf`: Performance improvement
- `test`: Adding tests
- `chore`: Maintenance

**Examples:**
```bash
feat(auth): add offline authentication support
fix(java): resolve detection on Windows
docs: update installation guide
refactor(download): simplify progress tracking
```

### Pull Request Guidelines

**Before submitting:**
- [ ] Code follows style guidelines
- [ ] Tests pass locally
- [ ] Documentation updated if needed
- [ ] No unnecessary files committed
- [ ] Commit messages are clear

**PR Description:**
- Explain what and why
- Link related issues
- List breaking changes
- Add screenshots for UI changes

### Code Review

Maintainers will review your PR for:
- Code quality and style
- Test coverage
- Documentation
- Performance impact
- Security implications

Be responsive to feedback and make requested changes.

## Common Tasks

### Adding a Tauri Command

1. **Define command in `main.rs`:**
   ```rust
   #[tauri::command]
   async fn my_command(param: String) -> Result<String, String> {
       Ok(format!("Received: {}", param))
   }
   ```

2. **Register in builder:**
   ```rust
   .invoke_handler(tauri::generate_handler![
       my_command,
       // ... other commands
   ])
   ```

3. **Call from frontend:**
   ```typescript
   const result = await invoke('my_command', { param: 'value' });
   ```

### Adding a UI Component

1. **Create component file:**
   ```svelte
   <!-- packages/ui/src/components/MyComponent.svelte -->
   <script lang="ts">
     let count = $state(0);
   </script>

   <button onclick={() => count++}>
     Count: {count}
   </button>
   ```

2. **Import and use:**
   ```svelte
   <script>
     import MyComponent from './components/MyComponent.svelte';
   </script>

   <MyComponent />
   ```

### Adding a Store

1. **Create store file:**
   ```typescript
   // packages/ui/src/stores/mystore.svelte.ts
   export class MyState {
     value = $state(0);
     
     increment() {
       this.value++;
     }
   }
   
   export const myState = new MyState();
   ```

2. **Use in components:**
   ```svelte
   <script>
     import { myState } from '../stores/mystore.svelte';
   </script>

   <button onclick={() => myState.increment()}>
     {myState.value}
   </button>
   ```

## Troubleshooting Development Issues

### Build Failures

**"cannot find -lwebkit2gtk"**
```bash
# Install WebKit dependencies
sudo apt install libwebkit2gtk-4.1-dev
```

**"pnpm not found"**
```bash
# Install pnpm
npm install -g pnpm@9
```

**"Rust version too old"**
```bash
# Update Rust
rustup update
```

### Runtime Issues

**"Failed to load dynamic library"**
- Rebuild: `cargo clean && cargo tauri dev`
- Check library paths
- Verify dependencies installed

**"CORS error"**
- Normal in dev mode
- Tauri handles CORS automatically

**"Hot reload not working"**
- Check Vite config
- Restart dev server
- Clear browser cache

## Resources

- [Tauri Documentation](https://v2.tauri.app/)
- [Svelte 5 Documentation](https://svelte.dev/docs)
- [Rust Book](https://doc.rust-lang.org/book/)
- [DropOut Repository](https://github.com/HydroRoll-Team/DropOut)

## Getting Help

- **Issues**: [GitHub Issues](https://github.com/HydroRoll-Team/DropOut/issues)
- **Discussions**: [GitHub Discussions](https://github.com/HydroRoll-Team/DropOut/discussions)
- **Documentation**: This site