activeadmin-quill_editor/docs/setup-activeadmin-gem.md

Setting Up an ActiveAdmin 4 Extension Gem (Combustion)

This guide mirrors the working setup used in this repo: ActiveAdmin 4.0.0.beta20 + Tailwind CSS v4 + Combustion test app.

1. Gem Dependencies

# Gemfile
source "https://rubygems.org"
gemspec

gem "rails", "~> 7.2"
gem "activeadmin", "4.0.0.beta20"
gem "sqlite3"
gem "puma"

gem "importmap-rails", "~> 2.0"
gem "propshaft"

gem "tailwindcss-rails", "~> 4.4.0"

group :development, :test do
  gem "combustion", "~> 1.3"
  gem "rspec-rails"
  gem "capybara"
end

2. Combustion Test App

bundle exec combust

3. config.ru Loading Order

# config.ru
require "rubygems"
require "bundler"

Bundler.setup(:default, :development)

require "combustion"
Combustion.initialize! :active_record, :action_controller, :action_view do
  config.load_defaults Rails::VERSION::STRING.to_f if Rails::VERSION::MAJOR >= 7
end

require "importmap-rails"
require "active_admin"
require "activeadmin_your_feature"

run Combustion::Application

4. Internal App Structure

cd spec/internal
mkdir -p app/admin app/assets/{builds,config,stylesheets} app/javascript

5. ActiveAdmin Setup

# spec/internal/config/initializers/active_admin.rb
ActiveAdmin.setup do |config|
  config.site_title = "Test App"
  config.authentication_method = false
  config.current_user_method = false
end

6. Tailwind Input + Config

/* spec/internal/app/assets/stylesheets/active_admin.tailwind.css */
@import "tailwindcss";
@config "../../../tailwind-active_admin.config.mjs";

/* Import your gem CSS if needed */
@import "your_gem/css";

// spec/internal/tailwind-active_admin.config.mjs
import { execSync } from "child_process";
import activeAdminPlugin from "@activeadmin/activeadmin/plugin";

const activeAdminPath = execSync("bundle show activeadmin", {
  encoding: "utf-8"
}).trim();

export default {
  content: [
    `${activeAdminPath}/vendor/javascript/flowbite.js`,
    `${activeAdminPath}/plugin.js`,
    `${activeAdminPath}/app/views/**/*.{arb,erb,html,rb}`,
    "./app/admin/**/*.{arb,erb,html,rb}",
    "./app/views/**/*.{arb,erb,html,rb}",
    "./app/javascript/**/*.js",
    "../../app/assets/**/*.{js,css}"
  ],
  darkMode: "selector",
  plugins: [activeAdminPlugin]
};

7. Tailwind Build Tasks

# spec/internal/lib/tasks/active_admin.rake
namespace :active_admin do
  desc "Build Active Admin Tailwind stylesheets"
  task build: :environment do
    command = [
      Rails.root.join("bin/tailwindcss").to_s,
      "-i", Rails.root.join("app/assets/stylesheets/active_admin.tailwind.css").to_s,
      "-o", Rails.root.join("app/assets/builds/active_admin.css").to_s,
      "-m"
    ]

    system(*command, exception: true)
  end
end

8. Tailwind Binstub

bundle binstubs tailwindcss-ruby --force

9. JS Entry

// spec/internal/app/javascript/active_admin.js
import "@activeadmin/activeadmin";
import "your_gem";

10. package.json (internal)

{
  "name": "internal",
  "private": true,
  "scripts": {
    "build:js": "node esbuild.config.js",
    "build:css": "bundle exec rake active_admin:build",
    "build": "npm run build:js && npm run build:css"
  },
  "devDependencies": {
    "@activeadmin/activeadmin": "^4.0.0-beta20",
    "esbuild": "^0.24.2"
  }
}

11. ActiveAdmin 4.0.0.beta20 Notes (from upgrade guide)

Version Requirements:

• Rails 7.2+ (Rails 7.0 and 7.1 are no longer supported)
• Ruby 3.2+ (Ruby 3.0 and 3.1 are no longer supported)

Breaking Changes from earlier v4 betas:

• _site_header.html.erb container class changed from sticky to fixed.
• active_admin.html.erb adds the pt-16 utility class.
• Tailwind v4 requires @import "tailwindcss" + @config.
• jQuery and jQuery UI removed; columns and tabs components removed.
• Replace default_main_content with render "show_default".
• Replace as: :datepicker with as: :date_picker.
• Replace active_admin_comments with active_admin_comments_for(resource).
• Replace attributes_table with attributes_table_for(resource) in sidebars.

New in beta20:

• Parent menu item linking support
• Improved comments pagination styling
• Better vertical spacing for has-many forms
• Pointer cursor restored on eligible buttons
• Various accessibility improvements