Role-Based Access Control (RBAC) & JWT Security Architecture - Learnille iHub

Overview

Learnille implements a multi-tiered security model utilizing JSON Web Tokens (JWT) for stateless session authentication and CASL / NestJS Guards for granular Role-Based Access Control (RBAC).

🔐 1. Authentication & Token Architecture

[ Client Application ] ---> POST /auth/login ---> [ NestJS Auth Controller ]
                                                        |
                                            Validate password hash (argon2)
                                                        |
                                                        v
[ Client Application ] <--- Return Tokens <--- [ Generate Access & Refresh Tokens ]
  - Access Token (Header: Bearer <jwt>)          - Short-lived (15 mins)
  - Refresh Token (HTTP-Only Cookie)             - Long-lived (7 days, stored in Redis)

Key Security Properties

Access Token Expiry: 15 minutes.
Refresh Token Rotation: Refresh tokens are single-use; issuing a new access token invalidates the previous refresh token in Redis.
Payload Sanitization: JWT payloads contain non-sensitive identifiers only (userId, email, role, permissions).

🛡 2. Role Hierarchy & Permission Matrix

Role	Scope & Allowed Capabilities
`STUDENT`	Enrolls in courses, streams purchased content, posts comments, leaves reviews, books consultations, manages own profile.
`INSTRUCTOR`	Inherits `STUDENT` permissions + creates/edits courses, uploads media assets, views student course analytics, manages instructor wallet payouts.
`CONSULTANT`	Inherits `STUDENT` permissions + creates consultation offers, configures availability slots, conducts 1-on-1 sessions, manages consultant wallet payouts.
`ADMIN`	System-wide administrative access: quality validation queue approvals/rejection, user account management, platform revenue reports, audit log inspection, payout execution.

🔒 3. NestJS Guard Implementation Standard

All protected controllers must include JwtAuthGuard and @ApiBearerAuth():

@ApiTags('Consultations')
@Controller('consultations')
@UseGuards(JwtAuthGuard, RolesGuard)
@ApiBearerAuth()
export class ConsultationController {
  @Post()
  @Roles(Role.CONSULTANT, Role.ADMIN)
  create(@CurrentUser() user: User, @Body(new ValidationPipe()) dto: CreateConsultationDto) {
    return this.consultationService.create(user, dto);
  }
}