Session Management

Learn how to effectively manage the lifecycle of sessions and JWT tokens. Session management is an important topic that directly affects user experience and security.

Session Management Overview

Session Store

Redis, PostgreSQLScalable storage

Session Expiration

Auto expirationSliding expiration

Token Refresh

Refresh TokenAccess Token reissue

Logout

Session invalidationToken blacklist

Session-Based Authentication

How Sessions Work

Session-based authentication is a method where the server stores the user’s login state on the server side. Understanding how it works helps you better handle security and scalability issues. Session Authentication Flow:

When user logs in, server generates a session ID
Session data (user ID, etc.) is stored in session store
Session ID is sent to client as a cookie
Each subsequent request authenticates user via session ID in cookie

Advantages:

Server has full control over sessions (can invalidate anytime)
Sensitive information is not exposed to client
Simple to implement and well-proven method

Disadvantages:

Stores state on server, requiring scalability considerations
Session store can become a single point of failure (SPOF)

Session Store Configuration

Memory Store (Development Only): Memory store should only be used in development environments. All sessions are lost when the server restarts, and sessions cannot be shared across multiple server instances.

// server.ts (Development environment)
import fastify from "fastify";
import fastifySession from "@fastify/session";
import fastifyCookie from "@fastify/cookie";

const app = fastify();

app.register(fastifyCookie);

app.register(fastifySession, {
  secret: process.env.SESSION_SECRET!,
  cookie: {
    secure: false, // Allow HTTP in development
    httpOnly: true,
    maxAge: 1000 * 60 * 60 * 24, // 1 day
  },
  saveUninitialized: false,
  // Uses memory store if store is not specified
});

Problems with Memory Store:

All sessions lost on server restart
Cannot share sessions across multiple server instances
Memory usage growth can degrade performance
Never use in production

Redis Store (Production): Using Redis as a session store is the industry standard for production environments. Redis is fast, scalable, and supports session sharing across multiple server instances.

npm install @fastify/redis connect-redis
# or
pnpm add @fastify/redis connect-redis

// server.ts (Production)
import fastify from "fastify";
import fastifySession from "@fastify/session";
import fastifyCookie from "@fastify/cookie";
import fastifyRedis from "@fastify/redis";
import RedisStore from "connect-redis";

const app = fastify();

// Redis connection
app.register(fastifyRedis, {
  host: process.env.REDIS_HOST || "localhost",
  port: parseInt(process.env.REDIS_PORT || "6379"),
  password: process.env.REDIS_PASSWORD,
  // Connection pool settings
  lazyConnect: false,
  enableReadyCheck: true,
});

app.register(fastifyCookie);

// Use Redis as session store
app.register(fastifySession, {
  secret: process.env.SESSION_SECRET!,
  store: new RedisStore({
    client: app.redis, // Use Fastify Redis client
    prefix: "sess:", // Session key prefix
    ttl: 60 * 60 * 24 * 7, // 7 days (in seconds)
  }),
  cookie: {
    secure: true, // HTTPS required
    httpOnly: true, // XSS prevention
    sameSite: "strict", // CSRF prevention
    maxAge: 1000 * 60 * 60 * 24 * 7, // 7 days
  },
  saveUninitialized: false,
  resave: false,
});

Redis Configuration Explained:

prefix: Prefix for session keys to distinguish from other data
ttl: Time To Live, automatic session expiration time (in seconds)
client: Redis client instance

Redis supports cluster mode for implementing high availability (HA). Using managed services like AWS ElastiCache or Azure Cache for Redis makes operations more convenient.

PostgreSQL Store (Alternative): If you’re already using PostgreSQL, you can use PostgreSQL as a session store without a separate Redis. However, performance is lower than Redis.

npm install connect-pg-simple
# or
pnpm add connect-pg-simple

import session from "express-session";
import connectPgSimple from "connect-pg-simple";
import pg from "pg";

const PgStore = connectPgSimple(session);
const pgPool = new pg.Pool({
  host: process.env.DB_HOST,
  port: parseInt(process.env.DB_PORT || "5432"),
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  database: process.env.DB_NAME,
});

app.register(fastifySession, {
  secret: process.env.SESSION_SECRET!,
  store: new PgStore({
    pool: pgPool,
    tableName: "sessions", // Session table name
  }),
  cookie: {
    secure: true,
    httpOnly: true,
    maxAge: 1000 * 60 * 60 * 24 * 7,
  },
});

Session Expiration Strategies

Fixed Expiration: Session expires unconditionally after a set time from creation. High security but may result in poor user experience.

app.register(fastifySession, {
  secret: process.env.SESSION_SECRET!,
  cookie: {
    maxAge: 1000 * 60 * 60 * 2, // Unconditional expiration after 2 hours
  },
  rolling: false, // Disable sliding expiration
});

Sliding Expiration: Session expiration time is renewed with each user activity. Suitable for “Remember Me” functionality with good user experience.

app.register(fastifySession, {
  secret: process.env.SESSION_SECRET!,
  cookie: {
    maxAge: 1000 * 60 * 60 * 24 * 7, // 7 days
  },
  rolling: true, // Renew expiration time on each request
  resave: false, // Save even if session unchanged
});

Hybrid Strategy: Set short expiration time initially, and apply longer expiration when “Remember Me” is selected.

class AuthModel extends BaseModelClass {
  @api({ httpMethod: "POST" })
  async login(params: {
    email: string;
    password: string;
    rememberMe?: boolean;
  }): Promise<{ user: User }> {
    const { email, password, rememberMe } = params;
    const context = Sonamu.getContext();
    
    // Authentication logic...
    const user = await this.authenticateUser(email, password);
    
    // Adjust session expiration based on Remember Me
    if (rememberMe) {
      context.request.session.cookie.maxAge = 1000 * 60 * 60 * 24 * 30; // 30 days
    } else {
      context.request.session.cookie.maxAge = 1000 * 60 * 60 * 2; // 2 hours
    }
    
    // Save login info to session
    await this.loginToSession(user);
    
    return { user };
  }
}

Session Data Management

Store only minimal information in sessions. Large session size degrades performance and increases storage costs.

// ✅ Good example: Store only minimal info
context.request.session.userId = user.id;
context.request.session.role = user.role;

// ❌ Bad example: Storing too much info
context.request.session.user = {
  id: user.id,
  email: user.email,
  username: user.username,
  bio: user.bio,
  profileImage: user.profileImage,
  preferences: user.preferences,
  // ... many fields
};

Accessing Session Data:

class UserModel extends BaseModelClass {
  @api({ httpMethod: "GET" })
  async getProfile(): Promise<{ user: User }> {
    const context = Sonamu.getContext();
    
    // Get user ID from session
    const userId = context.request.session.userId;
    
    if (!userId) {
      throw new Error("Not authenticated");
    }
    
    // Query latest info from database
    const rdb = this.getPuri("r");
    const user = await rdb
      .table("users")
      .where("id", userId)
      .first();
    
    return { user };
  }
}

JWT Token Management

How JWT Works

JWT (JSON Web Token) is a stateless authentication method. After the server creates a token, all information is contained within the token itself, so the server doesn’t need to store anything separately. JWT Structure:

header.payload.signature

Header: Token type and algorithm (e.g., {"alg": "HS256", "typ": "JWT"})
Payload: User information and claims (e.g., {"userId": 123, "role": "user"})
Signature: Signature to verify token integrity

JWT Advantages:

Good scalability as server doesn’t store state
Suitable for microservice environments
No separate lookup needed as information is contained in token itself

JWT Disadvantages:

Difficult to forcibly invalidate token from server
Token size is larger than cookies
If token is stolen, it can be used until expiration

Access Token and Refresh Token

Access Token is a short-lived token used for API requests. Usually has a short validity period of 15 minutes to 1 hour. Even if stolen, damage is minimized. Refresh Token is a long-lived token used to reissue Access Tokens. Usually has a validity period of 7 to 30 days and is stored on the server for management. Why use two tokens? If Access Token validity is set to 30 days:

If stolen, it can be abused for 30 days
User permission changes are not immediately reflected

With short Access Token and Refresh Token renewal:

Stolen Access Token is only valid for a short time
Permission changes can be reflected quickly
Refresh Token can be stored on server and invalidated

// auth/jwt.ts
import jwt from "jsonwebtoken";

const ACCESS_TOKEN_SECRET = process.env.ACCESS_TOKEN_SECRET!;
const REFRESH_TOKEN_SECRET = process.env.REFRESH_TOKEN_SECRET!;

/**
 * Generate Access Token (short-lived)
 */
export function generateAccessToken(user: User): string {
  return jwt.sign(
    {
      userId: user.id,
      email: user.email,
      role: user.role,
    },
    ACCESS_TOKEN_SECRET,
    {
      expiresIn: "15m", // 15 minutes
    }
  );
}

/**
 * Generate Refresh Token (long-lived)
 */
export function generateRefreshToken(user: User): string {
  return jwt.sign(
    {
      userId: user.id,
      // Minimal info in Refresh Token
    },
    REFRESH_TOKEN_SECRET,
    {
      expiresIn: "7d", // 7 days
    }
  );
}

/**
 * Verify Access Token
 */
export function verifyAccessToken(token: string) {
  try {
    return jwt.verify(token, ACCESS_TOKEN_SECRET);
  } catch (error) {
    return null;
  }
}

/**
 * Verify Refresh Token
 */
export function verifyRefreshToken(token: string) {
  try {
    return jwt.verify(token, REFRESH_TOKEN_SECRET);
  } catch (error) {
    return null;
  }
}

Security Notes:

Must use different secrets for Access Token and Refresh Token
Store Refresh Token on server to enable invalidation
To prevent XSS attacks, store tokens in httpOnly cookies instead of localStorage

Refresh Token Database Schema

CREATE TABLE refresh_tokens (
  id SERIAL PRIMARY KEY,
  user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
  token TEXT NOT NULL UNIQUE,
  expires_at TIMESTAMP NOT NULL,
  created_at TIMESTAMP DEFAULT NOW(),
  
  INDEX idx_user_id (user_id),
  INDEX idx_token (token),
  INDEX idx_expires_at (expires_at)
);

Token Refresh Implementation

class AuthModel extends BaseModelClass {
  /**
   * Refresh Access Token
   * 
   * Receives Refresh Token and issues new Access Token.
   * Verifies both token validity and database storage.
   */
  @api({ httpMethod: "POST" })
  async refreshToken(params: {
    refreshToken: string;
  }): Promise<{
    accessToken: string;
    refreshToken?: string; // For Refresh Token Rotation
  }> {
    const { refreshToken } = params;
    
    // 1. Verify Refresh Token
    const payload = verifyRefreshToken(refreshToken);
    
    if (!payload || typeof payload === "string") {
      throw new Error("Invalid refresh token");
    }
    
    // 2. Verify Refresh Token in database
    const rdb = this.getPuri("r");
    const storedToken = await rdb
      .table("refresh_tokens")
      .where("token", refreshToken)
      .where("user_id", payload.userId)
      .where("expires_at", ">", new Date())
      .first();
    
    if (!storedToken) {
      throw new Error("Refresh token not found or expired");
    }
    
    // 3. Query user info
    const user = await rdb
      .table("users")
      .where("id", payload.userId)
      .first();
    
    if (!user) {
      throw new Error("User not found");
    }
    
    // 4. Generate new Access Token
    const accessToken = generateAccessToken(user);
    
    // 5. Refresh Token Rotation (optional)
    // Renew Refresh Token together for enhanced security
    const newRefreshToken = generateRefreshToken(user);
    
    const wdb = this.getPuri("w");
    
    // Delete existing Refresh Token
    await wdb
      .table("refresh_tokens")
      .where("token", refreshToken)
      .delete();
    
    // Save new Refresh Token
    await wdb.table("refresh_tokens").insert({
      user_id: user.id,
      token: newRefreshToken,
      expires_at: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000), // 7 days
    });
    
    return {
      accessToken,
      refreshToken: newRefreshToken,
    };
  }
}

Refresh Token Rotation is a technique that issues a new Refresh Token each time one is used, enhancing security. Even if a token is stolen, only one of the thief or legitimate user can receive a new token, enabling quick detection of theft.

Token Invalidation (Logout)

JWT is valid until expiration by default, but can be forcibly invalidated using a blacklist.

class AuthModel extends BaseModelClass {
  /**
   * Logout
   * 
   * Deletes Refresh Token from database and
   * adds Access Token to blacklist.
   */
  @api({ httpMethod: "POST" })
  async logout(): Promise<{ success: boolean }> {
    const context = Sonamu.getContext();
    
    if (!context.user) {
      throw new Error("Not authenticated");
    }
    
    const wdb = this.getPuri("w");
    
    // 1. Delete all Refresh Tokens
    await wdb
      .table("refresh_tokens")
      .where("user_id", context.user.id)
      .delete();
    
    // 2. Add current Access Token to blacklist
    const authHeader = context.request.headers.authorization;
    if (authHeader && authHeader.startsWith("Bearer ")) {
      const token = authHeader.substring(7);
      
      // Calculate remaining validity time of Access Token
      const decoded = jwt.decode(token) as any;
      const expiresIn = decoded.exp - Math.floor(Date.now() / 1000);
      
      // Add to Redis blacklist (TTL is remaining token time)
      const redis = getRedisClient();
      await redis.setex(`blacklist:${token}`, expiresIn, "1");
    }
    
    return { success: true };
  }
  
  /**
   * Logout all sessions (including other devices)
   */
  @api({ httpMethod: "POST" })
  async logoutAll(): Promise<{ success: boolean }> {
    const context = Sonamu.getContext();
    
    if (!context.user) {
      throw new Error("Not authenticated");
    }
    
    const wdb = this.getPuri("w");
    
    // Delete all Refresh Tokens
    await wdb
      .table("refresh_tokens")
      .where("user_id", context.user.id)
      .delete();
    
    return { success: true };
  }
}

Token Blacklist Middleware

// auth/jwt.middleware.ts
import type { FastifyRequest, FastifyReply } from "fastify";

export async function checkTokenBlacklist(
  request: FastifyRequest,
  reply: FastifyReply
) {
  const authHeader = request.headers.authorization;
  
  if (!authHeader || !authHeader.startsWith("Bearer ")) {
    return;
  }
  
  const token = authHeader.substring(7);
  
  // Check blacklist in Redis
  const redis = getRedisClient();
  const isBlacklisted = await redis.exists(`blacklist:${token}`);
  
  if (isBlacklisted) {
    return reply.status(401).send({
      error: "Token has been revoked",
    });
  }
}

Practical Patterns

How to restrict concurrent access from multiple devices with one account.

class AuthModel extends BaseModelClass {
  @api({ httpMethod: "POST" })
  async login(params: {
    email: string;
    password: string;
  }): Promise<{ accessToken: string }> {
    const { email, password } = params;
    
    // Authentication...
    const user = await this.authenticateUser(email, password);
    
    const wdb = this.getPuri("w");
    
    // Delete all existing sessions (force logout)
    await wdb
      .table("refresh_tokens")
      .where("user_id", user.id)
      .delete();
    
    // Issue new tokens
    const accessToken = generateAccessToken(user);
    const refreshToken = generateRefreshToken(user);
    
    await wdb.table("refresh_tokens").insert({
      user_id: user.id,
      token: refreshToken,
      expires_at: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000),
    });
    
    return { accessToken };
  }
}

Cleanup Expired Sessions

Periodically delete expired Refresh Tokens to manage database size.

// tasks/cleanup-tokens.ts
import { task } from "sonamu";

/**
 * Delete expired Refresh Tokens at midnight every day
 */
@task({ cron: "0 0 * * *" })
export async function cleanupExpiredTokens() {
  const db = getDatabase();
  
  const result = await db
    .table("refresh_tokens")
    .where("expires_at", "<", new Date())
    .delete();
  
  console.log(`Deleted ${result} expired refresh tokens`);
}

Cautions

Session/Token Management Cautions:

Manage Session Secret and JWT Secret via environment variables
External session store like Redis is required for production
Store Refresh Token in database to enable invalidation
Set Access Token short, Refresh Token long
Set secure: true only when using HTTPS
httpOnly: true is required for XSS prevention
Use Redis TTL feature for blacklist

Next Steps

Authentication Setup

Building authentication system

Protected Routes

Permission control with Guards

Context

Learn more about Context

Workflows

Task scheduling

Get Started

Core Concepts

Database

API Development

Frontend Integration

Testing

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Troubleshooting

FAQ