An agile way to implement Countries, Regions, and Cities in a Ruby On Rails scaffold without the need to create additional tables

Ruby On Rails: 5, 6, 7

Add this line to your application's Gemfile:

gem 'countries_regions_and_cities_by_pete'

And then execute:

$ bundle install

Let's create a example for a Place scaffold:

1. Let's create a new rails app:

rails new myapp 

2. Create the database:

bundle exec rake db:create

3. Go to the application directory in Terminal and run the following command to create a scaffold for the Place model:

bundle exec rails g scaffold Place name:string description:text

4. Add this line to your application's Gemfile:

gem 'countries_regions_and_cities_by_pete'

5. Go to your application's directory in Terminal and run:

bundle install

6. Go to the application directory in Terminal and run the following command to install the necessary code and files from the gem:

bundle exec rake 'install_countries_regions_and_cities_by_pete[Place]'

7. Add jQuery to your layout file: /app/views/layouts/application.html.erb

<script src='/countries_regions_and_cities_by_pete/jquery-3.6.0.min.js'></script>

8. Paste this code to your _form.html.erb file: /app/views/places/_form.html.erb

<div class="field" id="country_field">
  <%= render partial: "shared/country_select_by_pete", locals: {model: form.object.class.name, label: "Country", selected: form.object.country} %>
  </div>
<div class="field" id="region_field">
  <%= render partial: "shared/region_select_by_pete", locals: {model: form.object.class.name, label: "Region / State", selected_country: form.object.country, selected: form.object.region} %>
  </div>
 <div class="field" id="city_field">
  <%= render partial: "shared/city_select_by_pete", locals: {model: form.object.class.name, label: "City", selected_region: form.object.region, selected_country: form.object.country, selected: form.object.city} %>
  </div>

9. Allow parameters (country,region and city) in your controller: /app/controllers/places_controller.rb

def place_params
   params.require(:place).permit(:name, :description, :address, :country, :region, :city)
end

Watch this video to see how it works

Bug reports and pull requests are welcome on GitHub at https://github.com/peterconsuegra/countries_regions_and_cities. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

Everyone interacting in the CountriesRegionsAndCitiesByPeterconsuegra project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.