How to implement flexible role-based access control with multiple user roles in Ruby on Rails?

Question

I'm building a complex SaaS application with Ruby on Rails and I'm trying to determine the best way to implement role-based access control (RBAC) to secure different parts of the app for different user roles.

Some specific requirements:

There are 5 main user roles - admin, manager, employee, customer, guest

• Admins can access all areas
• managers can access certain admin areas
• Employees can view their own content but not content for other employees
• Customers can only access their own customer account area
• Guests have read-only access to certain public content

I've looked at solutions like Pundit and Declarative Authorization but I'm not sure if they are robust enough for the complex permissions I need to implement. What is the recommended approach for flexible, maintainable RBAC in Rails with multiple user roles and permissions?

I've implemented basic role-based access control before in Rails using solutions like Pundit, but this case is more complex than what I've done in the past.

So far I've tried:

• Using Pundit policies for the main user roles. This works for simple cases but gets very cumbersome with complex permissions across different controllers/actions.

• Rolling my own permissions with if/elsif/else in controllers. This works but is not maintainable with a growing app and many roles.

• Looking at Declarative Authorization but the DSL seems limiting for my complex needs. I deally I'm looking for an RBAC solution that:

• Is easy to maintain as the app grows in scale and complexity

• Can handle permission logic across different models/controllers cleanly

• Allows me to add new roles and permissions without massive refactoring

• Has a non-verbose DSL or clean Ruby syntax for defining permissions

The options I've tried so far don't seem to offer the flexibility I need long-term. What am I missing? What approaches work well for complex multi-role RBAC in real Rails applications?

Answer 1

Use the 'cancancan' gem or 'Pundit' with custom enhancements:

Both 'cancancan' and 'Pundit' are popular authorization libraries in the Rails ecosystem. For complex RBAC scenarios, 'cancancan' or a customized 'Pundit' setup can be a good choice.

a. Define roles and abilities: Create a Role model and an Ability model. Each role can have a set of abilities associated with it. Abilities represent what actions a role can perform on specific resources (models).

class Role < ApplicationRecord
  has_many :abilities
end

class Ability < ApplicationRecord
  belongs_to :role
  # Define fields for model, controller, and action (e.g., model: 'User', action: 'create').
end

b. Authorization logic: Define custom logic within 'cancancan' or 'Pundit' to check permissions based on roles and abilities. Customize the DSL or policy classes to handle complex scenarios efficiently. Here's an example using 'cancancan':

class Ability
  include CanCan::Ability

  def initialize(user)
    # Define abilities here based on the user's role and permissions.
    can :read, :public_content
    if user.admin?
      can :manage, :all
    elsif user.manager?
      can :manage, :admin_area
    elsif user.employee?
      can :read, User, id: user.id
    elsif user.customer?
      can :read, Customer, user_id: user.id
    end
  end
end

c. Role assignment: Assign roles to users in your application. You can use a separate table to manage user roles or store roles as a field on the user model.