openhuman/docs/src-tauri/01-architecture.md

Rust Backend Architecture

Overview

The Tauri Rust backend provides native functionality for the AlphaHuman desktop application:

• System tray with background execution
• Deep link authentication
• Secure session storage (OS Keychain)
• Socket.io state management
• Native notifications
• Window management

Directory Structure

src-tauri/src/
├── lib.rs                      # Entry point, plugin registration, tray setup
├── main.rs                     # Binary entry (desktop)
├── commands/                   # Tauri IPC commands
│   ├── mod.rs
│   ├── auth.rs                 # Authentication commands
│   ├── socket.rs               # Socket state commands
│   ├── telegram.rs             # Telegram login commands
│   └── window.rs               # Window management commands
├── services/                   # Background services
│   ├── mod.rs
│   ├── session_service.rs      # Secure session storage (keychain)
│   ├── socket_service.rs       # Socket.io state management
│   └── notification_service.rs # Native notifications
├── models/                     # Data structures
│   ├── mod.rs
│   ├── auth.rs                 # Auth types (Session, User)
│   └── socket.rs               # Socket types (ConnectionStatus)
└── utils/                      # Configuration and helpers
    ├── mod.rs
    └── config.rs               # Environment configuration

Key Components

lib.rs - Application Entry

The main entry point that:

1. Registers Tauri plugins (opener, deep-link, autostart, notification)
2. Sets up system tray with Show/Hide and Quit menu
3. Handles macOS-specific window close behavior (minimize to tray)
4. Registers all IPC commands

Commands Layer

Commands are exposed to the frontend via Tauri's IPC:

Module	Commands	Purpose
auth	exchange_token, get_auth_state, logout, etc.	Authentication
socket	socket_connect, report_socket_connected, etc.	Socket state
telegram	start_telegram_login	Telegram OAuth
window	show_window, hide_window, toggle_window, etc.	Window control

Services Layer

Singleton services providing background functionality:

Service	Purpose	Storage
SessionService	Secure auth token storage	OS Keychain
SocketService	Socket.io state management	Memory + Events
NotificationService	Native notifications	N/A

Architecture Decisions

Socket.io Strategy

The frontend maintains the actual Socket.io connection, while Rust:

1. Stores connection parameters
2. Tracks connection state
3. Emits events to coordinate with frontend
4. Ensures socket stays connected when window is hidden

This approach is necessary because:

• Rust's Socket.io libraries have API compatibility issues
• The WebView maintains state when hidden (unlike browser tabs)
• Frontend JavaScript is better suited for Socket.io's event-driven model

Keychain Storage

Session tokens are stored in the OS keychain for security:

• macOS: Keychain
• Windows: Credential Manager
• Linux: Secret Service

Event Bridge Pattern

Rust communicates with the frontend via Tauri events:

// Rust emits event
app.emit("socket:should_connect", json!({ "backendUrl": url, "token": token }))

// Frontend listens
listen("socket:should_connect", (event) => {
  socketService.connect(event.payload.backendUrl, event.payload.token);
});

Plugin Dependencies

Plugin	Version	Purpose
tauri-plugin-opener	2	Open URLs in browser
tauri-plugin-deep-link	2.0.0	Handle outsourced:// URLs
tauri-plugin-autostart	2	Launch at login
tauri-plugin-notification	2	Native notifications

Cargo Dependencies

Crate	Purpose
tauri	Core framework with tray and macOS APIs
serde, serde_json	Serialization
reqwest	HTTP client
tokio	Async runtime
keyring	Secure credential storage
once_cell	Lazy static singletons
parking_lot	Fast mutexes
log, env_logger	Logging

Platform-Specific Behavior

macOS

• Window close button hides instead of quitting
• Dock icon click shows window
• LaunchAgent for autostart
• Keychain for secure storage

Windows/Linux

• Deep link registration at runtime
• Platform-specific credential storage
• Registry (Windows) or desktop file (Linux) autostart

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Next: Commands Reference