NestJS - how to check if JWT can access specific endpoint - node.js

Question

Let's say I have 3 endpoints: A is for generating JWT token, B for accessing data of user X and C for accessing data of user Y. Now, what I want to do is, that I can from recieved token somehow in controller guards figure out, if user can access endpoint.
So, token generated for user X can only access endpoint B, token generated for user Y can only access endpoint C.
Token has to be generated at endpoint A, since users sign in at same form.
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Answer 1

You Can do that by specifying in the payload a role, by this role you set a guard on each endpoint which role has the access to it. let me give an example:
I believe that you have a function where you fill you payload kind of this function :
createJwtPayload(user){
let data: JwtPayload = {
userData: user,
companyId : user.company.id,
role:user.role.name, // for us this where we specify the role for our User
};
......
}
Now We have to create guards we need to specify access for x endpoints
let start with Admin Guard:
#Injectable()
export class AdminGuard implements CanActivate {
async canActivate(context: ExecutionContext): Promise<boolean> {
const request = context.switchToHttp().getRequest();
if (!request.headers.authorization) {
return false;
}
request.user = await this.validateToken(request.headers.authorization);
if( request.user.role == ROLES.SUPER_ADMIN) {
return true;
}
return false;
}
async validateToken(auth: string) {
......
}
lets make the second guard we call it EmployeGuard :
....
#Injectable()
export class EmployeGuard implements CanActivate {
async canActivate(context: ExecutionContext): Promise<boolean> {
const request = context.switchToHttp().getRequest();
if (!request.headers.authorization) {
return false;
}
request.user = await this.validateToken(request.headers.authorization);
if( request.user.role == ROLES.COMPANY_ADMIN || request.user.role == ROLES.USER) {
return true;
}
return false;
}
async validateToken(auth: string) {
......
}
Now to use these guards we just need to use #UseGuards() in our endpoint :
#Post()
#UseGuards(AdminGuard)
async addCompany(#Res() res, #Body() createDto: CompanyDto) {
........
}
#Get(':companyID')
#UseGuards(EmployeGuard)
async getcompany(#Res() res, #Param('companyID') companyID) {
....
}
Bonus: you can #useGuards on the controller to make sure the all endpoints use it