types-formattor/src/middleware/auth.ts

utilities packages for request response next handler, middleware parser, payment token format, courier response format, notification response format

import {
    CanActivate,
    ExecutionContext,
    Injectable,
    UnauthorizedException,
} from '@nestjs/common';
import { Request } from 'express';
import { Reflector } from '@nestjs/core';
import { JwtService } from '@nestjs/jwt';
import { ConfigService } from '@nestjs/config';
import { IS_PUBLIC_KEY } from '../decorators/public.decorator';

@Injectable()
export class AuthGuard implements CanActivate {
    constructor(
        private jwtService: JwtService,
        private reflector: Reflector,
        private configService: ConfigService,
    ) { }

    async canActivate(context: ExecutionContext): Promise<boolean> {
        const isPublic = this.reflector.getAllAndOverride<boolean>(IS_PUBLIC_KEY, [
            context.getHandler(),
            context.getClass(),
        ]);
        if (isPublic) {
            return true;
        }

        const request = context.switchToHttp().getRequest();
        const token = this.extractTokenFromHeader(request);
        if (!token) {
            throw new UnauthorizedException();
        }
        try {
            const payload = await this.jwtService.verifyAsync(token, {
                secret: this.configService.get<string>('JWT_SECRET'),
            });
            // 💡 We're assigning the payload to the request object here
            // so that we can access it in our route handlers
            request.body = payload;
        } catch {
            throw new UnauthorizedException();
        }
        return true;
    }

    private extractTokenFromHeader(request: Request): string | undefined {
        const [type, token] = request.headers.authorization?.split(' ') ?? [];
        return type === 'Bearer' ? token : undefined;
    }
}