Madmin Static Models

Browse read-only, in-memory models in your Madmin admin.

Supports active_hash models out of the box — ActiveHash::Base, ActiveYaml::Base, ActiveJson::Base and ActiveFile::Base — with an adapter layer for adding other static backends (e.g. frozen_record) later.

Static resources get:

  • Index, show, search, sorting and pagination — all done in memory, no SQL
  • Automatic read-only behavior: no new/edit/delete links, write actions redirect away
  • Generator support: rails g madmin:install and rails g madmin:resource pick up static models

Installation

Add to your Gemfile:

gem "madmin-static_models"

Requires madmin >= 2.6.

Usage

Define a static model:

class Country < ActiveHash::Base
  fields :name, :code

  self.data = [
    {id: 1, name: "United States", code: "US"},
    {id: 2, name: "Canada", code: "CA"}
  ]
end

Generate its admin resource (or write it by hand):

rails g madmin:resource Country

class CountryResource < Madmin::Resource
  attribute :id, form: false
  attribute :name
  attribute :code
end

That's it — the resource shows up in Madmin like any other, minus the write actions.

How it works

The gem attaches to Madmin through its ActiveSupport load hooks (:madmin_resource, :madmin_resource_controller) and prepends small modules that answer differently for static models and call super for everything else:

  • Resource.readonly? returns true, which makes Madmin hide write links and block write actions
  • Resource.model_column_names comes from the adapter instead of the database
  • Pagination, sorting and search run over plain arrays in memory
  • show_path/edit_path are built manually since static records don't support polymorphic routing

Adding a backend

An adapter is a class with three methods. Register it and matching models are treated as static:

class FrozenRecordAdapter < Madmin::StaticModels::Adapter
  def self.handles?(model)
    model < ::FrozenRecord::Base
  end

  def self.column_names(model)
    [model.primary_key.to_s, *model.attributes].uniq
  end

  def self.models
    ::FrozenRecord::Base.descendants
  end
end

Madmin::StaticModels.register(FrozenRecordAdapter)

Development

bundle install
bundle exec rake test

License

MIT