how to set role in rails :::: https://altalogy.com/blog/rails-6-user-accounts-with-3-types-of-roles/

 https://altalogy.com/blog/rails-6-user-accounts-with-3-types-of-roles/

Authorization – CanCanCan

We use CanCanCan gem to restrict access to some parts of the app. Whatsmore, we grant different permissions for specific roles. Add to Gemfile:

gem 'cancancan'

Run:

$ bundle install

Next, use this command to generate ability class:

$ rails g cancan:ability

You can define abilities in app/models/ability.rb. But first, we have to set different roles. It’s up to you how you want to define roles. We will use three roles: superadmin, supervisor, and user. We add three boolean columns for each role in the user model. Let’s start by generating migration:

$ rails generate migration add_roles_to_users superadmin_role:boolean supervisor_role:boolean user_role:boolean

Before we run the migration, let’s edit it. Open db/migrate/xxx_add_roles_to_users.rb and adjust the code:

class AddRolesToUsers < ActiveRecord::Migration[5.2]

  def change

    add_column :users, :superadmin_role, :boolean, default: false

    add_column :users, :supervisor_role, :boolean, default: false

    add_column :users, :user_role, :boolean, default: true

  end

end

We’ve defined default values for superadmin and supervisor as a false, and true default value for user_role. Now we can run:

$ rake db:migrate

To verify current user’s role, you can use:

current_user.superadmin_role?

current_user.supervisor_role?

current_user.user_role?

Views

To display some elements only for users with a specific role, you can use:

<% if current_user.superadmin_role? || current_user.supervisor_role? %>

    <p>Visible only for superadmins and supervisors! </p>

<% end %>

Or you can use CanCanCan abilities:

<% if can? :manage, User %>

    <p>Visible only for superadmins and supervisors! </p>

<% end %>

And in app/model/ability.rb:

class Ability

  include CanCan::Ability

​

  def initialize(user)

    # Define abilities for the passed in user here. For example:

​

    user ||= User.new # guest user (not logged in)

    if user.superadmin_role?

      can :manage, :all

    end

    if user.supervisor_role?

      can :manage, User

    end

​

  end

end

Controllers
To authorize user access to controller’s actions, let’s add the following to a specific controller:
load_and_authorize_resource

It will use a before action to load the resource into an instance variable and authorize it for every action.

Next, let’s modify app/model/ability.rb:



user ||= User.new # guest user (not logged in)
if user.superadmin_role?
      can :manage, :all
      can :access, :rails_admin       # only allow admin users to access Rails Admin
      can :manage, :dashboard         # allow access to dashboard
end
if user.supervisor_role?
      can :manage, User
end