Ruby on Rails: Where to define global constants?

Question

I\'m just getting started with my first Ruby on Rails webapp. I\'ve got a bunch of different models, views, controllers, and so on.

I\'m wanting to find a good plac

Answer 1

As of Rails 4.2, you can use the config.x property:

# config/application.rb (or config/custom.rb if you prefer)
config.x.colours.options = %w[white blue black red green]
config.x.colours.default = 'white'

Which will be available as:

Rails.configuration.x.colours.options
# => ["white", "blue", "black", "red", "green"]
Rails.configuration.x.colours.default
# => "white"

Another method of loading custom config:

# config/colours.yml
default: &default
  options:
    - white
    - blue
    - black
    - red
    - green
  default: white
development:
  *default
production:
  *default

# config/application.rb
config.colours = config_for(:colours)

Rails.configuration.colours
# => {"options"=>["white", "blue", "black", "red", "green"], "default"=>"white"}
Rails.configuration.colours['default']
# => "white"

---

In Rails 5 & 6, you can use the configuration object directly for custom configuration, in addition to config.x. However, it can only be used for non-nested configuration:

# config/application.rb
config.colours = %w[white blue black red green]

It will be available as:

Rails.configuration.colours
# => ["white", "blue", "black", "red", "green"]