Example Glimmer DSL GUI app using ActiveRecord

This repository was originally created to satisfy my need for a kind of boilerplate using Glimmer DSL with ActiveRecord as an ORM over a sqlite3 database. At that time, I couldn't find any resources on it. Since then, Andy Maleh, OSS Author of Glimmer, reached out to me about his post, Using ActiveRecord with SQLite DB in a JRuby Desktop App. I decided to put together a tutorial to extend this idea further, including other migration tasks from ActiveRecord::Tasks::DatabaseTask, and an ability to run rake db:seed using the SeedLoader.

If you'd like to use this repository, just follow Setup. Otherwise, follow the ALTERNATIVE APPROACH.

Setup

1. Clone repository
2. Install dependencies: bundle install
3. Prepare database: rake db:prepare
4. Run app: glimmer run

ALTERNATIVE APPROACH

Without using this repository, just follow along with this tutorial.

Table of Contents

• Install Glimmer
• Scaffold a Glimmer demo app
• Commit remaining scaffolding
• Add dependencies
• Install dependencies
• Add db directory
• Add migration for contacts table
• Add database configuration
• Add a SQLite database with ActiveRecord
  • Add shared methods for database access
  • Add database connection
• Integrate DatabaseTasks with SeedLoader
• Add rake tasks for ActiveRecord migrations
• Wire up ActiveRecord tasks in Rakefile
• Verify rake tasks
• Prepare database
• Add Contact model
• Add seed data
• Import seed data
• Update demo view
• Run demo app
• Troubleshooting

Install Glimmer

See instructions at glimmer-dsl-libui

Scaffold a Glimmer demo app

glimmer "scaffold[demo]"
cd demo

Commit remaining scaffolding

This step is optional.

Glimmer makes an initial git commit and leaves a dirty tree, so to clean it up...

git add .
git commit -m "Add remaining scaffolding"

Add dependencies

after gem 'glimmer-dsl-libui' line

# Gemfile

gem 'activerecord', '~> 7.1', '>= 7.1.3.4'
gem 'sqlite3', '~> 1.4', force_ruby_platform: true

Install dependencies

bundle install

Add db directory

mkdir -p db/migrate

Add migration for contacts table

touch db/migrate/20240708135100_create_contacts.rb

# db/migrate/20240708135100_create_contacts.rb

require 'active_record'

class CreateContacts < ActiveRecord::Migration[7.1]
  def change
    create_table :contacts do |t|
      t.string     :first_name
      t.string     :last_name
      t.string     :email
      t.string     :phone
      t.string     :street
      t.string     :city
      t.string     :state_or_province
      t.string     :zip_or_postal_code
      t.string     :country
    end
  end
end

Add database configuration

mkdir config
touch config/database.yml

# config/database.yml

default: &default
  adapter: sqlite3
  pool: 5
  timeout: 5000

development:
  <<: *default
  database: db/demo.sqlite3

test:
  <<: *default
  database: db/test.sqlite3

Add a SQLite database with ActiveRecord

Add shared methods for database access

touch db/config.rb

# db/config.rb

class Demo
  module DB
    module Config
      def root
        File.expand_path('../..', __FILE__)
      end

      def file
        File.join(root, "config/database.yml")
      end

      def yaml
        # aliases: true fixes Psych::AliasesNotEnabled exception
        YAML.load_file(file, aliases: true)
      end

      def env
        ENV['ENV'] || 'development'
      end
    end
  end
end

Add database connection

touch db/connection.rb

# db/connection.rb

require 'active_record'
require_relative './config'

include Demo::DB::Config

ActiveRecord::Base.configurations = Demo::DB::Config::yaml
ActiveRecord::Base.establish_connection(Demo::DB::Config::env.to_sym)
ActiveRecord::Base.logger = ActiveSupport::Logger.new(STDOUT)

Integrate DatabaseTasks with SeedLoader

mkdir support
touch support/active_record_rake_tasks.rb

Add rake tasks for ActiveRecord migrations

# support/active_record_rake_tasks.rb

require_relative '../db/connection'

include ActiveRecord::Tasks

root = Demo::DB::Config::root

DatabaseTasks.root = root
DatabaseTasks.db_dir = File.join(root, 'db')
DatabaseTasks.migrations_paths = [File.join(root, 'db/migrate')]
DatabaseTasks.database_configuration = Demo::DB::Config::yaml

# The SeedLoader is Optional, if you don't want/need seeds you can skip setting it
class SeedLoader
  def initialize(seed_file)
    @seed_file = seed_file
  end

  def load_seed
    load @seed_file if File.exist?(@seed_file)
  end
end

DatabaseTasks.seed_loader = SeedLoader.new(File.join(root, 'db/seeds.rb'))
DatabaseTasks.env = Demo::DB::Config::env

load 'active_record/railties/databases.rake'

Wire up ActiveRecord tasks in Rakefile

# Rakefile

require './support/active_record_rake_tasks'

Verify rake tasks

rake -T

Add fix for "Don't know how to build task 'environment'" error

# Rakefile

Rake::Task.define_task(:environment)

Prepare database

rake db:prepare

Add Contact model

touch app/demo/model/contact.rb

# app/demo/model/contact.rb

class Contact < ActiveRecord::Base
end

Add seed data

touch db/seeds.rb
touch db/models.rb

# db/models.rb

model_dir = File.expand_path('../../app/demo/model', __FILE__)
Dir.glob(File.join(model_dir, '**', '*.rb')).each { |model| require model }

# db/seeds.rb

require 'active_record'
require_relative './connection'
require_relative "./models"

Contact.create(first_name: 'Chip',
               last_name: 'Castle',
               email: 'chip@chipcastle.com',
               phone: '555-555-5555',
               street: 'Any street',
               city: 'Inlet Beach',
               state_or_province: 'FL',
               zip_or_postal_code: '55555',
               country: 'US')

Import seed data

 rake db:seed

Update demo view

At the top of the file, replace the require 'demo/model/greeting' with:

# app/demo/view/demo.rb

require 'demo/model/contact'

Inside the before_body block, replace @greeting = Model::Greeting.new with:

@contact = Contact.first

Inside def launch method (after margined true line), remove the reference to the @greeting form entry and add the following code to verify ActiveRecord:

vertical_box {
  form {
    stretchy false

    entry {
      label 'First name'
      text <=> [@contact, :first_name]
    }
    entry {
      label 'Last name'
      text <=> [@contact, :last_name]
    }
    entry {
      label 'Email'
      text <=> [@contact, :email]
    }
    entry {
      label 'Phone'
      text <=> [@contact, :phone]
    }
    entry {
      label 'Street address'
      text <=> [@contact, :street]
    }
    entry {
      label 'City'
      text <=> [@contact, :city]
    }
    entry {
      label 'State/Province'
      text <=> [@contact, :state_or_province]
    }
    entry {
      label 'Zip/Postal code'
      text <=> [@contact, :zip_or_postal_code]
    }
    entry {
      label 'Country'
      text <=> [@contact, :country]
    }
  }
}

Run demo app

  glimmer run

Troubleshooting

1. If you encounter a Don't know how to build task environment error, try adding this to the bottom of your Rakefile:

# Rakefile

Rake::Task.define_task(:environment)

2. When an ActiveRecord::EnvironmentMismatchError exception is raised, run this from the shell:

    rake db:environment:set ENV=development

3. Running rake db:version raises an NameError: uninitialized constant Rails (NameError) exception, which can be fixed with this hack (open to other suggestions, but I gotta move on.)

# Rakefile

class Rails
  def env
    ENV['ENV'] || 'development'
  end
end

Copyright

Copyright (c) 2024 Chip Castle. See LICENSE for further details.