Super Admin

By default Rhino includes an admin dashboard that allows you to manage your application. This dashboard is built using the ActiveAdmin gem and themed with arctic_admin and installs activeadmin_addons gem to add some extra functionality.

The dashboard is accessible at /admin and requires an admin user to log in.

Configuration

The admin dashboard configuration is in config/initializers/active_admin.rb and can be altered to the project needs.

Generating an admin resource

To generate an admin resource with Rhino defaults, use the following command:

rails g rhino:resource ModelName

info

This generator is included by default if you run rails g rhino:model.

This will generate a model in the app/admin folder with the default Rhino configuration for the model, like so:

ActiveAdmin.register ModelName do
  rhino_filters
  rhino_permit_params
end

That provides the default filters and permit params for the model and index and other configuration options can be added as needed.

Generating an admin resource with ActiveAdmin defaults

If more control is needed over the resource, generate or replace an ActiveAdmin resource with the following command:

rails g admin:resource ModelName

Security

ActiveAdmin 3+ requires ransack 4 which has a system for whitelisting attributes and scopes for searching. Rhino by default allows the same attributes and associations for viewing and for filtering as for reading.

To customize the attributes and associations that can be searched, you can override the ransackable_attributes, ransackable_associations, and ransackable_filters methods in your model.

    def ransackable_attributes(_auth_object = nil)
      super + ['my_special_attribute']
    end

    def ransackable_associations(_auth_object = nil)
      super + ['my_special_scope']
    end

    def ransackable_filters(auth_object = nil)
      super + ['my_special_filter']
    end
  end

Optimizing select filters

ActiveAdmin’s default select filter loads all records from the database which can cause significant performance issues. To avoid this, a lazy typeahead select filter can be created using activeadmin_addons, and the Ransack gem used by ActiveAdmin.

Imagine we have an InvoiceLineItem table, that belongs to a UsersRole, that in turn belongs to a User. If we want a “User“ filter in the InvoiceLineItem Index page, we would do something like this:

app/admin/invoice_line_items.rb

ActiveAdmin.register InvoiceLineItem do
  preserve_default_filters!
  remove_filter :users_role # remove original filter
  filter :users_role_user_id, # this name must contain the relationships path from the model from the index page until the user table, so invoice_line_item -> users_role -> user. the engine will do a join.
    label: "User",
    as: :search_select_filter,
    url: proc { admin_users_path }, # AJAX endpoint
    fields: %w[name nickname email], # columns in the looked up table to be compared against
    minimum_input_length: 2,
    method_model: User, # original table
    width: "190px", # necessary for fixing a UI bug
    display_name: "full_nickname_and_email", # custom display name that gives you more flexibility to use whatever you want
    order_by: "name"
end

Create a json view for the admin_users_path to return a custom attribute that will be shown in the results select box.

app/views/admin/users/index.json.jbuilder

json.array!(@users) do |user|
  json.extract! user, :id, :full_nickname_and_email
end

Finish up by implementing the custom display field in the User model:

app/models/user.rb

def full_nickname_and_email
  "#{nickname || name} - #{email}"
end

info

jbuilder is no longer included in Rhino by default. You will need to add it to your Gemfile.