Making a variable available throughout the entire application?

Question

in my rails 3 app, I want to define a variable like so:

PERSONAL_DOMAINS = %w[
  @126.com
  @163.com
  @aim.com
  @aol.com
]

I then want to be able to use this in user.rb for validations like so:

return true if PERSONAL_DOMAINS.any? { |rule| "@#{domain}".include? rule }

I also want to use it in another model.

Like so:

domain_rules = [PERSONAL_DOMAINS]
domain_rules.each { |rule| return false if !domain.match(rule).nil? }

With Rails, where and how should you define this list of PERSONAL_DOMAINS? YML, config, initializer? And then how do you use it correctly?

Thanks

Possible duplicate of http://stackoverflow.com/questions/3598785/where-to-put-global-variables-in-rails-3 — Gardner Bickford, Mar 25 '13 at 20:53
This is probably something you need to put in a YAML file and use an initializer to load it. — Artem Kalinchuk, Mar 25 '13 at 20:57
how would you define this type of variable in a YAML? Also any performance issues? — AnApprentice, Mar 25 '13 at 20:58
@AnApprentice Performance shouldn't be an issue since it only loads on application start. For loading YAML files, check this question: http://stackoverflow.com/questions/592554/best-way-to-create-custom-config-options-for-my-rails-app — Artem Kalinchuk, Mar 25 '13 at 21:03

score 3 · Accepted Answer · answered Mar 25 '13 at 21:48

There are 2 ways I'd consider doing this assuming the values don't change in different environments, in both cases I think you should put it in an initializer like:

config/initializers/personal_ip_addresses.rb

Then you could simply have a file with the constant:

  PERSONAL_DOMAINS = %w[
      @126.com
      @163.com
      @aim.com
      @aol.com
    ]

You'd use it simply as you have above:

return true if PERSONAL_DOMAINS.any? { |rule| "@#{domain}".include? rule }

OR it you wanted to go the config route:

YourApplicationClass::Application.config.personal_domains = %w[
      @126.com
      @163.com
      @aim.com
      @aol.com
    ]

and you'd use it like this:

Rails.configuration.personal_domains

personally I try to keep it simple and would go with the constant.

The "config route" meaning defining your variable like config.my_variable = 10 inside the class block of your application.rb file — Jeffrey Kozik, Oct 14 '22 at 01:43

Richard Jordan · Answer 2 · 2013-03-25T21:00:19.873

You can define this in application.rb if you'd like it available to the whole app.

For example if you define something under

module MyApp
  class Application < Rails::Application

    PERSONAL_DOMAINS = %w[
      @126.com
      @163.com
      @aim.com
      @aol.com
    ]
    etc.

Then you can call it later as MyApp::Application::PERSONAL_DOMAINS

If that's what you really want. However, it's probably best to set up an initializer file to do this and keep it in that one place, easily changeable.

score 1 · Answer 3 · answered Mar 25 '13 at 21:29

1

Have you tried configatron?

I generally use it for all configuration variables, and it works great!

answered Mar 25 '13 at 21:29

tackleberry

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Making a variable available throughout the entire application?

3 Answers3