RBAC (Role based access control)

In this guide, we'll explore how to handle role-based access control (RBAC) or role-based permissions in Xano. RBAC is a security measure that ensures users can only access and execute certain API endpoints based on their assigned roles. Let's dive into two different methods to enforce RBAC in Xano.

Method 1: Using Preconditions

1. Set up User Roles: Start by defining user roles in your database. In this example, we have an `enum` field called `role` in the `user` table, with values like `admin` and `staff`.
2. Require User Authentication: For the API endpoint where you want to enforce RBAC, ensure user authentication is required. This means users must be logged in and have a valid JSON Web Token (JWT) to access the endpoint.
3. Get the Authenticated User Record: In your function stack, the first step is to get the authenticated user's record by looking up their ID from the JWT. You can use the `auth.userId` field value to retrieve the user's record.
4. Set a Precondition: Next, set a precondition that checks the user's role. In the precondition, you can use an expression like `request.role == 'admin'`, where `request` is the user's record. This condition must be true for the function stack to continue executing.
5. Set an Error Message: If the precondition fails, you can set an error type (e.g., `access denied`) and an optional error message to be displayed to the user.
6. Test the Endpoint: Run the API endpoint with different user roles to verify that only users with the required role can access and execute the endpoint's functionality.

Method 2: Using Extras

1. Set up Extras: Extras allow you to include additional information in the JWT during user authentication (sign-up or login). In this method, you'll store the user's role in the JWT's extras payload.
2. Modify the Login Endpoint: In your login API endpoint, locate the step where the authentication token is created. Here, you can use the `set` filter to define a path (e.g., `extras.role`) and set its value to the user's role from the database.
3. Require User Authentication: As with the first method, the API endpoint where you want to enforce RBAC should require user authentication.
4. Set a Precondition: Instead of getting the user record, you can set a precondition that checks the user's role stored in the JWT's extras payload. For example, `extras.role == 'admin'`.
5. Test the Endpoint: When testing within Xano, make sure to retrieve the JWT from the login endpoint that includes the extras payload. The quick auth token lookup doesn't include the extras information.

Both methods are secure and effective for implementing RBAC in Xano. The choice between the two depends on your preference and project requirements.

Remember, RBAC is crucial for ensuring data security and controlling access to sensitive information or functionality within your application. By following these steps, you can easily implement role-based permissions in Xano, catering to different user roles and their associated access levels.