我可以否定 NestJS 的 Guard 吗？

Question

I have AuthGuard from @nestjs/passport used on one my method (route) like this:

  @UseGuards(AuthGuard('jwt'))
  @Get('profile')
  getProfile(@Req() req) {
    return this.userService.findOne(req.user.id);
  }

Can I negate this guard, so only users without JWT can go trough ? I do not want users with JWT in header to access login/register route accidentally.

Answer 1

As bashleigh said in her comment, you can create your own guard that checks for a jwt and rejects if it comes in. A simple example could be something like

@Injectable()
export class NoJwtGuard implements CanActivate {
  canActivate(context: ExecutionContext): boolean {
    const req = context.switchToHttp().getRequest();
    const auth = req.headers['Authroization'];
    // as you should not have any authorization headers you an reject if the header exists
    return !auth;
  }
}

While it isn't possible to immediately negate a built in guard, you could also extend the AuthGuard('jwt') and then in your custom implementation of canActivate you could return !super.canActivate(context)