ATAuth - AT Protocol Authentication Library #

A complete, plug-and-play authentication system for AT Protocol (Bluesky) OAuth integration.

Components #

Component	Description
gateway/	Node.js OAuth gateway server
src/	Rust token verification library
ts/	TypeScript/React frontend utilities

Features #

• OAuth Gateway: Ready-to-deploy AT Protocol OAuth server
• Token Verification: Secure HMAC-SHA256 with constant-time comparison
• Session Management: Trait-based storage with SQLite and PostgreSQL backends
• Rate Limiting: IP-based rate limiting with configurable thresholds
• Input Validation: DID and handle format validation
• TypeScript Support: Full TypeScript/React utilities for frontend integration

Architecture #

┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│  Your Frontend  │────▶│  ATAuth Gateway │────▶│   Bluesky PDS   │
│  (React/Next)   │     │   (Node.js)     │     │ (OAuth Provider)│
└─────────────────┘     └─────────────────┘     └─────────────────┘
        │                       │
        │ token                 │ HMAC secret
        ▼                       ▼
┌─────────────────┐     ┌─────────────────┐
│  Your Backend   │────▶│  Token Verify   │
│  (Rust/Node)    │     │  (atauth lib)   │
└─────────────────┘     └─────────────────┘

Installation #

Rust #

Add to your Cargo.toml:

[dependencies]
atauth = { git = "https://github.com/Cache8063/atauth" }

Or with specific features:

[dependencies]
atauth = { git = "https://github.com/Cache8063/atauth", features = ["session-sqlite", "rate-limit"] }

TypeScript/JavaScript #

npm install atauth
# or
pnpm add atauth

Quick Start #

Rust - Basic Token Verification #

use atauth::{TokenVerifier, TokenPayload};

// Create a verifier with your HMAC secret (shared with auth gateway)
let verifier = TokenVerifier::new(b"your-secret-key");

// Verify a token from the auth gateway
match verifier.verify("token-from-client") {
    Ok(payload) => {
        println!("Authenticated: {} ({})", payload.handle, payload.did);
        // payload.user_id contains app-specific user ID if linked
    }
    Err(e) => {
        eprintln!("Auth failed: {}", e);
    }
}

Rust - With Session Store #

use atauth::{TokenVerifier, SessionManager};
use atauth::session::SqliteSessionStore;

// Setup
let verifier = TokenVerifier::new(b"your-secret-key");
let session_store = SqliteSessionStore::new("sessions.db")?;
let sessions = SessionManager::new(session_store);

// On login
if let Ok(payload) = verifier.verify(token) {
    let session = sessions.create_session(&payload, token.to_string())?;
    // Return session.token to client as session cookie
}

// On subsequent requests
match sessions.validate(session_token) {
    Ok(session) => {
        // User is authenticated
        println!("User: {}", session.handle);
    }
    Err(_) => {
        // Invalid or expired session
    }
}

// On logout
sessions.invalidate(session_token)?;

Rust - With Rate Limiting #

use atauth::rate_limit::{RateLimiter, RateLimiterConfig};
use std::time::Duration;

let config = RateLimiterConfig::default()
    .with_max_attempts(5)
    .with_lockout(Duration::from_secs(300));

let limiter = RateLimiter::new(config);

// Before authentication attempt
let client_ip = "192.168.1.1".parse().unwrap();
if let Err(e) = limiter.check(&client_ip) {
    return Err(e); // Rate limited
}

// After failed attempt
limiter.record_failure(&client_ip);

// After successful attempt
limiter.record_success(&client_ip);

TypeScript - React Integration #

import { initAuthStore, useAuthStore } from 'atauth/react';

// Initialize once at app startup
initAuthStore({
  gatewayUrl: 'https://auth.example.com',
  appId: 'myapp',
  callbackUrl: 'https://myapp.com/auth/callback',
});

function LoginButton() {
  const { isAuthenticated, user, login, logout, isLoading } = useAuthStore();

  if (isLoading) {
    return <div>Loading...</div>;
  }

  if (isAuthenticated) {
    return (
      <div>
        <span>Welcome, {user?.handle}!</span>
        <button onClick={logout}>Logout</button>
      </div>
    );
  }

  return <button onClick={() => login()}>Login with Bluesky</button>;
}

TypeScript - Manual Token Handling #

import {
  decodeToken,
  handleCallback,
  isOAuthCallback,
  redirectToAuth
} from 'atauth';

// Redirect to auth
redirectToAuth({
  gatewayUrl: 'https://auth.example.com',
  appId: 'myapp',
  callbackUrl: window.location.origin + '/callback',
});

// Handle callback page
if (isOAuthCallback()) {
  const result = handleCallback({ gatewayUrl: 'https://auth.example.com' });

  if (result.success) {
    console.log('Logged in as:', result.user?.handle);
    // Redirect to app
    window.location.href = result.returnTo || '/';
  } else {
    console.error('Auth failed:', result.error);
  }
}

Token Format #

Tokens follow a JWT-like structure: base64url(payload).base64url(signature)

Payload Structure #

{
  "did": "did:plc:abc123...",
  "handle": "user.bsky.social",
  "user_id": 42,
  "app_id": "myapp",
  "iat": 1699900000,
  "exp": 1699903600,
  "nonce": "random-string"
}

API Reference #

Rust #

TokenVerifier #

• new(secret: &[u8]) - Create verifier with HMAC secret
• from_hex(hex: &str) - Create from hex-encoded secret
• from_base64(b64: &str) - Create from base64-encoded secret
• verify(token: &str) -> Result<TokenPayload> - Verify and decode token
• sign(payload: &TokenPayload) -> Result<String> - Sign a payload (for gateways)

SessionManager<S: SessionStore> #

• new(store: S) - Create manager with store
• create_session(payload, token) - Create session from token
• validate(token) - Validate and optionally extend session
• invalidate(token) - Delete session
• invalidate_all_for_did(did) - Delete all sessions for user
• cleanup() - Remove expired sessions

RateLimiter #

• new(config) - Create with configuration
• check(ip) - Check if IP can attempt auth
• record_failure(ip) - Record failed attempt
• record_success(ip) - Clear on success

TypeScript #

Token Utilities #

• decodeToken(token) - Decode without verification
• isTokenExpired(payload) - Check expiration
• getTokenRemainingSeconds(payload) - Time until expiry
• isValidDid(did) - Validate DID format
• isValidHandle(handle) - Validate handle format

OAuth Utilities #

• redirectToAuth(config, state?) - Start OAuth flow
• handleCallback(config) - Process callback
• isOAuthCallback() - Check if on callback page
• buildLogoutUrl(config) - Get logout URL

React Hooks #

• useAuthStore() - Main auth hook
• useUser() - Get current user
• useIsAuthenticated() - Check auth status
• useNeedsRefresh() - Check if token needs refresh

Security Considerations #

• Server-side verification: Always verify tokens server-side. Client-side decoding is for display only.
• Constant-time comparison: Signature verification uses constant-time comparison to prevent timing attacks.
• Rate limiting: Enable rate limiting in production to prevent brute force attacks.
• HTTPS only: Always use HTTPS in production.
• Secure secrets: Store HMAC secrets securely, never in client code.

License #

MIT