Class: Rails::Application

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

Overview

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.

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, #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, instance, 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.



110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
 
# 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

Instance Attribute Details

#assets ⇒ Object

Returns the value of attribute assets



101
102
103
 
# File 'railties/lib/rails/application.rb', line 101

def assets
  @assets
end

#reloaders ⇒ Object (readonly)

Returns the value of attribute reloaders



103
104
105
 
# File 'railties/lib/rails/application.rb', line 103

def reloaders
  @reloaders
end

#sandbox ⇒ Object Also known as: sandbox?

Returns the value of attribute sandbox



101
102
103
 
# File 'railties/lib/rails/application.rb', line 101

def sandbox
  @sandbox
end

Class Method Details

.inherited(base) ⇒ Object 



88
89
90
91
 
# File 'railties/lib/rails/application.rb', line 88

def inherited(base)
  super
  base.instance
end

Instance Method Details

#add_lib_to_load_path! ⇒ 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.



267
268
269
270
271
272
 
# File 'railties/lib/rails/application.rb', line 267

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

#call(env) ⇒ Object

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



141
142
143
144
145
 
# 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

#config ⇒ Object

:nodoc:



311
312
313
 
# File 'railties/lib/rails/application.rb', line 311

def config #:nodoc:
  @config ||= Application::Configuration.new(find_root_with_flag("config.ru", Dir.pwd))
end

#config=(configuration) ⇒ Object

:nodoc:



315
316
317
 
# File 'railties/lib/rails/application.rb', line 315

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

#console(&blk) ⇒ Object

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



237
238
239
 
# File 'railties/lib/rails/application.rb', line 237

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.



193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
 
# 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" => config.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) ⇒ Object

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



243
244
245
 
# File 'railties/lib/rails/application.rb', line 243

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

#helpers_paths ⇒ Object

:nodoc:



345
346
347
 
# File 'railties/lib/rails/application.rb', line 345

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



298
299
300
301
302
303
 
# File 'railties/lib/rails/application.rb', line 298

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) 


135
136
137
 
# File 'railties/lib/rails/application.rb', line 135

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.



225
226
227
 
# File 'railties/lib/rails/application.rb', line 225

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

#initializers ⇒ Object

:nodoc:



305
306
307
308
309
 
# File 'railties/lib/rails/application.rb', line 305

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.



248
249
250
 
# File 'railties/lib/rails/application.rb', line 248

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

#key_generator ⇒ Object

Return the application’s KeyGenerator



153
154
155
156
157
158
159
160
161
162
163
164
 
# 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(config.secret_token)
    end
  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.



184
185
186
187
188
189
 
# 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

#migration_railties ⇒ Object

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

While when running initializers we need engines in reverse order here when copying migrations from railties we need then in the same order as given by railties_order



374
375
376
 
# File 'railties/lib/rails/application.rb', line 374

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.



218
219
220
 
# File 'railties/lib/rails/application.rb', line 218

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

#reload_routes! ⇒ Object

Reload application routes regardless if they changed or not.



148
149
150
 
# File 'railties/lib/rails/application.rb', line 148

def reload_routes!
  routes_reloader.reload!
end

#require_environment! ⇒ Object

:nodoc:



274
275
276
277
 
# File 'railties/lib/rails/application.rb', line 274

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

#routes_reloader ⇒ Object

:nodoc:



279
280
281
 
# File 'railties/lib/rails/application.rb', line 279

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

#runner(&blk) ⇒ Object

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



231
232
233
 
# File 'railties/lib/rails/application.rb', line 231

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

#secrets ⇒ Object

:nodoc:



319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
 
# File 'railties/lib/rails/application.rb', line 319

def secrets #:nodoc:
  @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

    secrets
  end
end

#secrets=(secrets) ⇒ Object

:nodoc:



337
338
339
 
# File 'railties/lib/rails/application.rb', line 337

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

#to_app ⇒ Object

:nodoc:



341
342
343
 
# File 'railties/lib/rails/application.rb', line 341

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.



286
287
288
289
290
291
292
293
294
 
# File 'railties/lib/rails/application.rb', line 286

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