Build Reusable Identity System with authId + OTP & Auth Middlewares (Universal Access Control)

🧩 Description

Build a reusable identity system with support for:

• ✅ authId (safe external identifier)

• ✅ internalAuthId (private DB reference)

• ✅ OTP verification middleware (isOtpVerified)

• ✅ verifyToken middleware for JWT/session validation

• ✅ Middleware for isBlocked, isDeleted, isValidated, etc.

• ✅ Global access in all modules (Todo, Product, Contact, etc.)

• This is the foundation of FastKit’s identity and access management, allowing you to plug in access control to any route.

🧱 Why This Is Important

• 💼 Used in every application that needs secure user logic

• 📦 Easy to reuse across multiple features/modules

• 🔐 Centralizes authId, flags, and token/OTP verification

• 🔁 Prevents boilerplate in every controller or route

🟢 Difficulty Level: Intermediate – Advanced

You should be comfortable with:

• TypeScript + Express

• JWT & token handling

• Writing middleware

• Using flags (boolean access control)

• OTP flows (via DB or cache)

✅ Tasks

📁 Proposed File Structure

src/
 |
│   
├── features/
│   └── Otp/
│       └── v1/
│           ├── Otp.model.ts
│           ├── Otp.middleware.ts # Middle Ware to Verify Otp , restrictToOwner.ts
│           └── Otp.constant.ts
              └── Otp.utils.ts
               # other 

📜 Auth.model.ts (Partial)

export interface IAuthUser {
  authId: string;
  internalAuthId: string;
  isEmailVerified: boolean;
  isOtpVerified: boolean;
  isValidated: boolean;
  isBlocked: boolean;
  isDeleted: boolean;
  ...
}

vExample Usage:

router.get(
  '/dashboard',
  verifyToken,
  FlagsUtils.check({ isValidated: true, isBlocked: false }),
  dashboardController.show
);

🔐 restrictToOwner.ts Middleware

export const restrictToOwner = (getOwnerAuthIdFn: (req) => string) => {
  return (req, res, next) => {
    if (req.user?.authId !== getOwnerAuthIdFn(req)) {
      return res.status(403).json({ message: 'Unauthorized access' });
    }
    next();
  };
};

Use in any module like Todo:

router.delete(
  '/todo/:id',
  verifyToken,
  restrictToOwner(req => req.todo.authId),
  todoController.delete
);

---

📦 Auth.constant.ts

export const AUTH_ERRORS = {
  BLOCKED: 'Account is blocked',
  OTP_REQUIRED: 'OTP verification required',
  VALIDATION_REQUIRED: 'User not validated',
  UNAUTHORIZED: 'Unauthorized',
};

---

📘 README.md for This Module

✅ Include:

• How authId works

• When to use verifyToken

• How to plug checkFlags middleware

• How to restrict a route to logged-in, verified users

Example:

import {
  verifyToken,
  checkFlags,
  verifyOtp,
  restrictToOwner,
} from 'fastkit-auth';

router.get(
  '/user/profile',
  verifyToken,
  checkFlags({ isValidated: true }),
  userController.getProfile
);

---

🎯 Expected Outcome

[x] Every feature uses authId for ownership checks

[x] Middleware for all common identity checks

[x] OTP validation logic fully reusable

[x] Cleaner, secure route protection

[x] Easy extension to new modules

---

🙋🏻‍♂️ Looking For

• Help adding rate-limiting for OTP

• Option to use Redis for OTP/session store

• authId indexing support (Mongoose)

• Tests for middleware logic

• Add support for 2FA, IP/device validation in future

🔁 Final Usage Pattern

router.post(
  '/secure-data',
  verifyToken,
  verifyOtp,
  checkFlags({ isValidated: true, isBlocked: false }),
  SecureController.handle
);