class Rails::Application

Parent:
Engine

In Rails 3.0, a Rails::Application object was introduced which is nothing more than an Engine but with the responsibility of coordinating the whole boot process.

Initialization

Rails::Application is responsible for executing all railties and engines initializers. It also executes some bootstrap initializers (check Rails::Application::Bootstrap) and finishing initializers, after all the others are executed (check Rails::Application::Finisher).

Configuration

Besides providing the same configuration as Rails::Engine and Rails::Railtie, the application object has several specific configurations, for example “cache_classes”, “consider_all_requests_local”, “filter_parameters”, “logger” and so forth.

Check Rails::Application::Configuration to see them all.

Routes

The application object is also responsible for holding the routes and reloading routes whenever the files change in development.

Middlewares

The Application is also responsible for building the middleware stack.

Booting process

The application is also responsible for setting up and executing the booting process. From the moment you require “config/application.rb” in your app, the booting process goes like this:

1)  require "config/boot.rb" to setup load paths
2)  require railties and engines
3)  Define Rails.application as "class MyApp::Application < Rails::Application"
4)  Run config.before_configuration callbacks
5)  Load config/environments/ENV.rb
6)  Run config.before_initialize callbacks
7)  Run Railtie#initializer defined by railties, engines and application.
    One by one, each engine sets up its load paths, routes and runs its config/initializers/* files.
8)  Custom Railtie#initializers added by railties, engines and applications are executed
9)  Build the middleware stack and run to_prepare callbacks
10) Run config.before_eager_load and eager_load! if eager_load is true
11) Run config.after_initialize callbacks

Multiple Applications

If you decide to define multiple applications, then the first application that is initialized will be set to Rails.application, unless you override it with a different application.

To create a new application, you can instantiate a new instance of a class that has already been created:

class Application < Rails::Application
end

first_application  = Application.new
second_application = Application.new(config: first_application.config)

In the above example, the configuration from the first application was used to initialize the second application. You can also use the initialize_copy on one of the applications to create a copy of the application which shares the configuration.

If you decide to define rake tasks, runners, or initializers in an application other than Rails.application, then you must run those these manually.

Attributes

assets[RW]
reloaders[R]
sandbox[RW]
sandbox?[RW]

Public Class Methods

inherited(base) Show source
Calls superclass method 
# File railties/lib/rails/application.rb, line 88
def inherited(base)
  super
  base.instance
end
new(initial_variable_values = {}, &block) Show source
Calls superclass method 
# File railties/lib/rails/application.rb, line 110
def initialize(initial_variable_values = {}, &block)
  super()
  @initialized       = false
  @reloaders         = []
  @routes_reloader   = nil
  @app_env_config    = nil
  @ordered_railties  = nil
  @railties          = nil
  @message_verifiers = {}

  Rails.application ||= self

  add_lib_to_load_path!
  ActiveSupport.run_load_hooks(:before_configuration, self)

  initial_variable_values.each do |variable_name, value|
    if INITIAL_VARIABLES.include?(variable_name)
      instance_variable_set("@#{variable_name}", value)
    end
  end

  instance_eval(&block) if block_given?
end

Public Instance Methods

call(env) Show source

Implements call according to the Rack API. It simply dispatches the request to the underlying middleware stack.

Calls superclass method 
# File railties/lib/rails/application.rb, line 141
def call(env)
  env["ORIGINAL_FULLPATH"] = build_original_fullpath(env)
  env["ORIGINAL_SCRIPT_NAME"] = env["SCRIPT_NAME"]
  super(env)
end
console(&blk) Show source

Sends any console called in the instance of a new application up to the console method defined in Rails::Railtie.

# File railties/lib/rails/application.rb, line 237
def console(&blk)
  self.class.console(&blk)
end
env_config() Show source

Stores some of the Rails initial environment parameters which will be used by middlewares and engines to configure themselves.

Calls superclass method 
# File railties/lib/rails/application.rb, line 193
def env_config
  @app_env_config ||= begin
    validate_secret_key_config!

    super.merge({
      "action_dispatch.parameter_filter" => config.filter_parameters,
      "action_dispatch.redirect_filter" => config.filter_redirect,
      "action_dispatch.secret_token" => secrets.secret_token,
      "action_dispatch.secret_key_base" => secrets.secret_key_base,
      "action_dispatch.show_exceptions" => config.action_dispatch.show_exceptions,
      "action_dispatch.show_detailed_exceptions" => config.consider_all_requests_local,
      "action_dispatch.logger" => Rails.logger,
      "action_dispatch.backtrace_cleaner" => Rails.backtrace_cleaner,
      "action_dispatch.key_generator" => key_generator,
      "action_dispatch.http_auth_salt" => config.action_dispatch.http_auth_salt,
      "action_dispatch.signed_cookie_salt" => config.action_dispatch.signed_cookie_salt,
      "action_dispatch.encrypted_cookie_salt" => config.action_dispatch.encrypted_cookie_salt,
      "action_dispatch.encrypted_signed_cookie_salt" => config.action_dispatch.encrypted_signed_cookie_salt,
      "action_dispatch.cookies_serializer" => config.action_dispatch.cookies_serializer
    })
  end
end
generators(&blk) Show source

Sends any generators called in the instance of a new application up to the generators method defined in Rails::Railtie.

# File railties/lib/rails/application.rb, line 243
def generators(&blk)
  self.class.generators(&blk)
end
initialized?() Show source

Returns true if the application is initialized.

# File railties/lib/rails/application.rb, line 135
def initialized?
  @initialized
end
initializer(name, opts={}, &block) Show source

Sends the initializers to the initializer method defined in the Rails::Initializable module. Each Rails::Application class has its own set of initializers, as defined by the Initializable module.

# File railties/lib/rails/application.rb, line 225
def initializer(name, opts={}, &block)
  self.class.initializer(name, opts, &block)
end
isolate_namespace(mod) Show source

Sends the isolate_namespace method up to the class method.

# File railties/lib/rails/application.rb, line 248
def isolate_namespace(mod)
  self.class.isolate_namespace(mod)
end
key_generator() Show source

Return the application's KeyGenerator

# File railties/lib/rails/application.rb, line 153
def key_generator
  # number of iterations selected based on consultation with the google security
  # team. Details at https://github.com/rails/rails/pull/6952#issuecomment-7661220
  @caching_key_generator ||= begin
    if secrets.secret_key_base
      key_generator = ActiveSupport::KeyGenerator.new(secrets.secret_key_base, iterations: 1000)
      ActiveSupport::CachingKeyGenerator.new(key_generator)
    else
      ActiveSupport::LegacyKeyGenerator.new(secrets.secret_token)
    end
  end
end
message_verifier(verifier_name) Show source

Returns a message verifier object.

This verifier can be used to generate and verify signed messages in the application.

It is recommended not to use the same verifier for different things, so you can get different verifiers passing the verifier_name argument.

Parameters

  • verifier_name - the name of the message verifier.

Examples

message = Rails.application.message_verifier('sensitive_data').generate('my sensible data')
Rails.application.message_verifier('sensitive_data').verify(message)
# => 'my sensible data'

See the ActiveSupport::MessageVerifier documentation for more information.

# File railties/lib/rails/application.rb, line 184
def message_verifier(verifier_name)
  @message_verifiers[verifier_name] ||= begin
    secret = key_generator.generate_key(verifier_name.to_s)
    ActiveSupport::MessageVerifier.new(secret)
  end
end
rake_tasks(&block) Show source

If you try to define a set of rake tasks on the instance, these will get passed up to the rake tasks defined on the application's class.

# File railties/lib/rails/application.rb, line 218
def rake_tasks(&block)
  self.class.rake_tasks(&block)
end
reload_routes!() Show source

Reload application routes regardless if they changed or not.

# File railties/lib/rails/application.rb, line 148
def reload_routes!
  routes_reloader.reload!
end
runner(&blk) Show source

Sends any runner called in the instance of a new application up to the runner method defined in Rails::Railtie.

# File railties/lib/rails/application.rb, line 231
def runner(&blk)
  self.class.runner(&blk)
end
secrets() Show source

Returns secrets added to config/secrets.yml.

Example:

development:
  secret_key_base: 836fa3665997a860728bcb9e9a1e704d427cfc920e79d847d79c8a9a907b9e965defa4154b2b86bdec6930adbe33f21364523a6f6ce363865724549fdfc08553
test:
  secret_key_base: 5a37811464e7d378488b0f073e2193b093682e4e21f5d6f3ae0a4e1781e61a351fdc878a843424e81c73fb484a40d23f92c8dafac4870e74ede6e5e174423010
production:
  secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
  namespace: my_app_production

Rails.application.secrets.namespace returns my_app_production in the production environment.

# File railties/lib/rails/application.rb, line 333
def secrets
  @secrets ||= begin
    secrets = ActiveSupport::OrderedOptions.new
    yaml = config.paths["config/secrets"].first
    if File.exist?(yaml)
      require "erb"
      all_secrets = YAML.load(ERB.new(IO.read(yaml)).result) || {}
      env_secrets = all_secrets[Rails.env]
      secrets.merge!(env_secrets.symbolize_keys) if env_secrets
    end

    # Fallback to config.secret_key_base if secrets.secret_key_base isn't set
    secrets.secret_key_base ||= config.secret_key_base
    # Fallback to config.secret_token if secrets.secret_token isn't set
    secrets.secret_token ||= config.secret_token

    secrets
  end
end

© 2004–2016 David Heinemeier Hansson
Licensed under the MIT License.