Class: Rails::Application

Inherits:
Engine show all
Defined in:
lib/rails/application.rb,
lib/rails/application/finisher.rb,
lib/rails/application/bootstrap.rb,
lib/rails/application/configuration.rb,
lib/rails/application/routes_reloader.rb,
lib/rails/application/default_middleware_stack.rb

Overview

An Engine 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 them manually.

Defined Under Namespace

Modules: Bootstrap, Finisher Classes: Configuration, DefaultMiddlewareStack, RoutesReloader

Constant Summary collapse

INITIAL_VARIABLES = 
[:config, :railties, :routes_reloader, :reloaders,
:routes, :helpers, :app_env_config, :secrets]

Constants inherited from Railtie

Railtie::ABSTRACT_RAILTIES

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Engine

#app, #call, #eager_load!, endpoint, #endpoint, find, #helpers, isolate_namespace, #load_console, #load_generators, #load_runner, #load_seed, #load_tasks, #railties, #routes, #routes?

Methods inherited from Railtie

abstract_railtie?, #configure, configure, console, generators, railtie_name, #railtie_namespace, rake_tasks, respond_to_missing?, runner, subclasses

Methods included from Initializable

included, #run_initializers

Constructor Details

#initialize(initial_variable_values = {}, &block) ⇒ Application

Returns a new instance of Application.



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# File 'lib/rails/application.rb', line 123

def initialize(initial_variable_values = {}, &block)
  super()
  @initialized       = false
  @reloaders         = []
  @routes_reloader   = nil
  @app_env_config    = nil
  @ordered_railties  = nil
  @railties          = nil
  @message_verifiers = {}
  @ran_load_hooks    = false

  @executor          = Class.new(ActiveSupport::Executor)
  @reloader          = Class.new(ActiveSupport::Reloader)
  @reloader.executor = @executor

  # are these actually used?
  @initial_variable_values = initial_variable_values
  @block = block
end

Instance Attribute Details

#assets ⇒ Object

Returns the value of attribute assets.



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# File 'lib/rails/application.rb', line 114

def assets
  @assets
end

#executor ⇒ Object (readonly)

Returns the value of attribute executor.



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# File 'lib/rails/application.rb', line 116

def executor
  @executor
end

#reloader ⇒ Object (readonly)

Returns the value of attribute reloader.



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# File 'lib/rails/application.rb', line 116

def reloader
  @reloader
end

#reloaders ⇒ Object (readonly)

Returns the value of attribute reloaders.



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# File 'lib/rails/application.rb', line 116

def reloaders
  @reloaders
end

#sandbox ⇒ Object Also known as: sandbox?

Returns the value of attribute sandbox.



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# File 'lib/rails/application.rb', line 114

def sandbox
  @sandbox
end

Class Method Details

.add_lib_to_load_path!(root) ⇒ Object

This method is called just after an application inherits from Rails::Application, allowing the developer to load classes in lib and use them during application configuration.

class MyApplication < Rails::Application
  require "my_backend" # in lib/my_backend
  config.i18n.backend = MyBackend
end

Notice this method takes into consideration the default root path. So if you are changing config.root inside your application definition or having a custom Rails application, you will need to add lib to $LOAD_PATH on your own in case you need to load files in lib/ during the application configuration as well.



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# File 'lib/rails/application.rb', line 320

def self.add_lib_to_load_path!(root) #:nodoc:
  path = File.join root, "lib"
  if File.exist?(path) && !$LOAD_PATH.include?(path)
    $LOAD_PATH.unshift(path)
  end
end

.create(initial_variable_values = {}, &block) ⇒ Object 



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# File 'lib/rails/application.rb', line 98

def create(initial_variable_values = {}, &block)
  new(initial_variable_values, &block).run_load_hooks!
end

.find_root(from) ⇒ Object 



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# File 'lib/rails/application.rb', line 102

def find_root(from)
  find_root_with_flag "config.ru", from, Dir.pwd
end

.inherited(base) ⇒ Object 



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# File 'lib/rails/application.rb', line 87

def inherited(base)
  super
  Rails.app_class = base
  add_lib_to_load_path!(find_root(base.called_from))
  ActiveSupport.run_load_hooks(:before_configuration, base)
end

.instance ⇒ Object 



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# File 'lib/rails/application.rb', line 94

def instance
  super.run_load_hooks!
end

Instance Method Details

#config ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 364

def config #:nodoc:
  @config ||= Application::Configuration.new(self.class.find_root(self.class.called_from))
end

#config=(configuration) ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 368

def config=(configuration) #:nodoc:
  @config = configuration
end

#config_for(name, env: Rails.env) ⇒ Object

Convenience for loading config/foo.yml for the current Rails env.

Example:

# config/exception_notification.yml:
production:
  url: http://127.0.0.1:8080
  namespace: my_app_production
development:
  url: http://localhost:3001
  namespace: my_app_development

# config/environments/production.rb
Rails.application.configure do
  config.middleware.use ExceptionNotifier, config_for(:exception_notification)
end



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# File 'lib/rails/application.rb', line 224

def config_for(name, env: Rails.env)
  if name.is_a?(Pathname)
    yaml = name
  else
    yaml = Pathname.new("#{paths["config"].existent.first}/#{name}.yml")
  end

  if yaml.exist?
    require "erb"
    (YAML.load(ERB.new(yaml.read).result) || {})[env] || {}
  else
    raise "Could not load configuration. No such file - #{yaml}"
  end
rescue Psych::SyntaxError => e
  raise "YAML syntax error occurred while parsing #{yaml}. " \
    "Please note that YAML must be consistently indented using spaces. Tabs are not allowed. " \
    "Error: #{e.message}"
end

#console(&blk) ⇒ Object

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



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# File 'lib/rails/application.rb', line 290

def console(&blk)
  self.class.console(&blk)
end

#env_config ⇒ Object

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



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# File 'lib/rails/application.rb', line 245

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,
      "action_dispatch.cookies_digest" => config.action_dispatch.cookies_digest
    )
  end
end

#generators(&blk) ⇒ Object

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



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# File 'lib/rails/application.rb', line 296

def generators(&blk)
  self.class.generators(&blk)
end

#helpers_paths ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 410

def helpers_paths #:nodoc:
  config.helpers_paths
end

#initialize!(group = :default) ⇒ Object

Initialize the application passing the given group. By default, the group is :default



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# File 'lib/rails/application.rb', line 351

def initialize!(group = :default) #:nodoc:
  raise "Application has been already initialized." if @initialized
  run_initializers(group, self)
  @initialized = true
  self
end

#initialized? ⇒ Boolean

Returns true if the application is initialized.

Returns:

  • (Boolean) 


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# File 'lib/rails/application.rb', line 144

def initialized?
  @initialized
end

#initializer(name, opts = {}, &block) ⇒ Object

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.



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# File 'lib/rails/application.rb', line 278

def initializer(name, opts = {}, &block)
  self.class.initializer(name, opts, &block)
end

#initializers ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 358

def initializers #:nodoc:
  Bootstrap.initializers_for(self) +
  railties_initializers(super) +
  Finisher.initializers_for(self)
end

#isolate_namespace(mod) ⇒ Object

Sends the isolate_namespace method up to the class method.



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# File 'lib/rails/application.rb', line 301

def isolate_namespace(mod)
  self.class.isolate_namespace(mod)
end

#key_generator ⇒ Object

Returns the application’s KeyGenerator



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# File 'lib/rails/application.rb', line 168

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 ||=
    if secrets.secret_key_base
      unless secrets.secret_key_base.kind_of?(String)
        raise ArgumentError, "`secret_key_base` for #{Rails.env} environment must be a type of String, change this value in `config/secrets.yml`"
      end
      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

#message_verifier(verifier_name) ⇒ Object

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.



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# File 'lib/rails/application.rb', line 201

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

#migration_railties ⇒ Object

Return an array of railties respecting the order they’re loaded and the order specified by the railties_order config.

While running initializers we need engines in reverse order here when copying migrations from railties ; we need them in the order given by railties_order.



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# File 'lib/rails/application.rb', line 430

def migration_railties # :nodoc:
  ordered_railties.flatten - [self]
end

#rake_tasks(&block) ⇒ Object

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.



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# File 'lib/rails/application.rb', line 271

def rake_tasks(&block)
  self.class.rake_tasks(&block)
end

#reload_routes! ⇒ Object

Reload application routes regardless if they changed or not.



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# File 'lib/rails/application.rb', line 163

def reload_routes!
  routes_reloader.reload!
end

#require_environment! ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 327

def require_environment! #:nodoc:
  environment = paths["config/environment"].existent.first
  require environment if environment
end

#routes_reloader ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 332

def routes_reloader #:nodoc:
  @routes_reloader ||= RoutesReloader.new
end

#run_load_hooks! ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 148

def run_load_hooks! # :nodoc:
  return self if @ran_load_hooks
  @ran_load_hooks = true

  @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
  self
end

#runner(&blk) ⇒ Object

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



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# File 'lib/rails/application.rb', line 284

def runner(&blk)
  self.class.runner(&blk)
end

#secrets ⇒ Object

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.



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# File 'lib/rails/application.rb', line 386

def secrets
  @secrets ||= begin
    secrets = ActiveSupport::OrderedOptions.new
    files = config.paths["config/secrets"].existent
    files = files.reject { |path| path.end_with?(".enc") } unless config.read_encrypted_secrets
    secrets.merge! Rails::Secrets.parse(files, env: Rails.env)

    # 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

#secrets=(secrets) ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 402

def secrets=(secrets) #:nodoc:
  @secrets = secrets
end

#to_app ⇒ Object

:nodoc:



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# File 'lib/rails/application.rb', line 406

def to_app #:nodoc:
  self
end

#watchable_args ⇒ Object

Returns an array of file paths appended with a hash of directories-extensions suitable for ActiveSupport::FileUpdateChecker API.



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# File 'lib/rails/application.rb', line 339

def watchable_args #:nodoc:
  files, dirs = config.watchable_files.dup, config.watchable_dirs.dup

  ActiveSupport::Dependencies.autoload_paths.each do |path|
    dirs[path.to_s] = [:rb]
  end

  [files, dirs]
end