IntrospectiveAdmin

IntrospectiveAdmin is a Rails Plugin for DRYing up ActiveAdmin configurations by laying out simple defaults and including nested relations according to the models' accepts_nested_attributes_for :relation declarations.

Documentation

In your Gemfile:

gem 'introspective_admin'

And bundle install. In app/admin/my_admin.rb:

class MyAdmin < IntrospectiveAdmin::Base
  def self.include_virtual_attributes
    %w(password)
  end

  def self.exclude_params
    %w(fields to exclude from the admin screen)
  end

  register MyModel do
    # It yields the ActiveAdmin DSL context back, allowing further configuration to
    # be added here, just as you would normally, to the Admin::MyModelController
    # namespace.
  end
end

Registering MyModel will set up the index, show, and form configurations for every attribute, virtual attribute listed in MyAdmin.include_virtual_attributes (e.g. a password field for a Devise model), and nested association on the model excluding those in MyAdmin.exclude_params. It will link to associated records (if they have ActiveAdmin screens), perform eager loading of nested associations, and permit parameters for every non-excluded attribute on the model.

Customizing select box options for associations is done by adding an "options_for_X" class method on the administrated model:

class MyModel < ActiveRecord::Base
  belongs_to :parent
  has_many :other_models
  accepts_nested_attributes_for :other_models, :allow_destroy => true

  def self.options_for_parent(instance_of_my_model)
    Parent.order(:appelation).map.{|p| ["#{p.appelation}", p.id] } 
  end
end

IntrospectiveAdmin will detect nested polymorphic relations and attempt to handle them using virutal attributes that you must add to the model instance, plus a class method for the select box options, using a shared delimiter string for the compound ID. E.g. here we use a hyphen:

class MyModel < ActiveRecord::Base
  belongs_to :poly_model, polymorphic: true
  accepts_nested_attributes_for :poly_model, :allow_destroy => true

  def self.options_for_poly_model
    PolyModel.all.map { |i| [ "#{i.class}: #{i.name}", "#{i.class}-#{i.id}"] }
  end

  def poly_model_assign
    poly_model.present? ? "#{poly_model_type}-#{poly_model_id}" : nil
  end

  def poly_model_assign=(value)
    self.poly_model_type,self.poly_model_id = value.split('-')
  end

end

Dependencies

Tool	Description
ActiveAdmin	The current master branch or, when it's released, version >1.0