Accessing Config from Application.Rb in Controller (Rails 3)

Accessing config from application.rb in Controller (Rails 3)

I believe you've got a slightly incorrect idea behind what your expectations for the config/application.rb is providing you. The ActiveRecord::Base and ActiveController::Base eigenclasses use the Rails::Application::Configuration class that is configured in config/application.rb. The attributes aren't available in classes that descend from either of the Base classes, nor their eigenclasses. This is why you are running into errors in ApplicationController.

There are generally two ways to make configuration initializations in a Rails app. The first way is to create a configuration module and then load values into it via initializer:

First, create a Twiter Config module:

#lib/twitter_config.rb
module TwitterConfig
  def self.config
    @@config ||= {}
  end

  def self.config=(hash)
    @@config = hash
  end
end

Create a YAML config file:

# config/twitter.yaml
development: &base
  key: "foo"
  secret: "bar"

test:
 <<: *base
 key: "foo2"

production:
  <<: *base
  secret: "barbar"

Alternatively, if you don't intend to add config/twitter.yaml to your SCM, you can just skip this and set the key and secret via environment variables. This would be the suggested solution for an application with a public SCM repository deploying on Heroku.

Then load and set the value via an initializer:

#config/initializers/01_twitter.rb
require 'twitter_config'

TwitterConfig.config = YAML.load_file("config/config.yml")[Rails.env].symbolize_keys

It's generally a best practice to number your initializer files as Rails will load them in order according to their filename. If you are initializing a datastore and that is critical for other steps, then it needs the lowest number. Alternatively, if you are using environment variables, this would be the init file:

#config/initializers/01_twitter.rb
require 'twitter_config'

TwitterConfig.config[:key] = ENV['twitter_config_key']
TwitterConfig.config[:secret] = ENV['twitter_config_secret']

Throughout the Rails application, you now have access to the config values with TwitterConfig.config[:key] & TwitterConfig.config[:secret]. You can include the module as well, just watch out for conflicts.

You can also just load the values as a global constant. It feels a bit ugly to me though:

#config/application.rb
TWITTER_CONFIG = YAML.load_file("config/twitter.yaml")[Rails.env]

How to read ruby on rails config values from within the application controller

The class method ActionController::Base.session_options returns a hash of the configuration options for the session.

So in your case you want ActionController::Base.session_options[:domain]

How do I access a Rails configuration value during runtime?

For Rails 2, you can do:

Rails.configuration.cache_classes

If you ever switch to Rails 3, it'll be different; you can access the same value with:

Rails.application.config.cache_classes

How to access configuration flag (set from config/environments/development.rb) from a controller?

The config object referred to in environments/*.rb is accessible by

Rails.application.config

Update rails config file from Controller

IMHO it's should be avoided. If nature of your config is dynamic (changes in time) then you should just read it from DB as you read User data or whatever.
If it's static then you may keep it in hash (YAML file, when config changes you just deploy your app). If settings change frequently I would recommend db.

Rails 3 Migration and application.rb

Trying renaming your app/controllers/application.rb to application_controller.rb.

I think Rails is expecting your controller to be named with a _controller suffix, and the application.rb you have in your controllers folder isn't following that convention.

Rails 3: application.rb not loading?

Is the AuthenticatedSystem module mixed in to your application_controller?

If so, then methods there will not be automatically available in the views.

You need to add something like:

helper :check_author_role

... in your application_controller, after mixing in the AuthenticatedSystem module.

How to get variable in sorcery.rb at controller

If you have an instance of User you can do it this way:

User.new.sorcery_config.activation_token_expiration_period

How to define custom configuration variables in Rails?

Update 1

Very recommended: I'm going with Rails Config gem nowadays for the fine grained control it provides.

Update2

If you want a quick solution, then check Jack Pratt's answer below.

Although my original answer below still works, this answer is now outdated. I recommend looking at updates 1 and 2.

Original Answer:

For a quick solution, watching the "YAML Configuration File" screen cast by Ryan Bates should be very helpful.

In summary:

# config/initializers/load_config.rb
APP_CONFIG = YAML.load_file("#{Rails.root}/config/config.yml")[Rails.env]

# application.rb
if APP_CONFIG['perform_authentication']
  # Do stuff
end

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