BoardAuthGuard

BoardAuthGuard is the abstract class that consumers implement to authenticate users for both REST API requests and WebSocket connections.

interface AuthenticatedUser {
    userId: string;
    displayName: string;
}

abstract class BoardAuthGuard {
    abstract validateConnection(token: string): Promise<AuthenticatedUser | null>;
    abstract validateRequest(token: string): Promise<AuthenticatedUser | null>;
}

Methods

validateConnection

Validates a token from a WebSocket connection (the token field in JoinMessage). Returns the authenticated user, or null to reject the connection.

validateRequest

Validates a Bearer token from an HTTP request's Authorization header. Returns the authenticated user, or null to reject the request.

Implementation Example

import { BoardAuthGuard, type AuthenticatedUser } from '@hfu.digital/boardkit-nestjs';
import { verify } from 'jsonwebtoken';

class JwtAuthGuard extends BoardAuthGuard {
    async validateConnection(token: string): Promise<AuthenticatedUser | null> {
        return this.verifyToken(token);
    }

    async validateRequest(token: string): Promise<AuthenticatedUser | null> {
        return this.verifyToken(token);
    }

    private async verifyToken(token: string): Promise<AuthenticatedUser | null> {
        try {
            const payload = verify(token, process.env.JWT_SECRET!) as {
                sub: string;
                name: string;
            };
            return {
                userId: payload.sub,
                displayName: payload.name,
            };
        } catch {
            return null;
        }
    }
}

Where It's Used

Context	Method Called	Token Source
REST API controllers	`validateRequest()`	`Authorization: Bearer <token>` header
WebSocket gateway (join)	`validateConnection()`	`token` field in `JoinMessage`

When authentication fails:

REST: The controller returns a 401 or 403 response
WebSocket: The gateway emits an error message (AUTH_FAILED) and disconnects the client

Testing

Use MockAuthGuard from the testing utilities for unit tests:

import { MockAuthGuard } from '@hfu.digital/boardkit-nestjs';

const authGuard = new MockAuthGuard();
// All tokens are accepted, returning a test user

See Testing for more details.