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, runner, subclasses

Methods included from Initializable

included, #run_initializers

Constructor Details

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

Returns a new instance of Application.



127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
 
# File 'lib/rails/application.rb', line 127

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.



118
119
120
 
# File 'lib/rails/application.rb', line 118

def assets
  @assets
end

#executor ⇒ Object (readonly)

Returns the value of attribute executor.



120
121
122
 
# File 'lib/rails/application.rb', line 120

def executor
  @executor
end

#reloader ⇒ Object (readonly)

Returns the value of attribute reloader.



120
121
122
 
# File 'lib/rails/application.rb', line 120

def reloader
  @reloader
end

#reloaders ⇒ Object (readonly)

Returns the value of attribute reloaders.



120
121
122
 
# File 'lib/rails/application.rb', line 120

def reloaders
  @reloaders
end

#sandbox ⇒ Object Also known as: sandbox?

Returns the value of attribute sandbox.



118
119
120
 
# File 'lib/rails/application.rb', line 118

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.



328
329
330
331
332
333
 
# File 'lib/rails/application.rb', line 328

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 



102
103
104
 
# File 'lib/rails/application.rb', line 102

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

.find_root(from) ⇒ Object 



106
107
108
 
# File 'lib/rails/application.rb', line 106

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

.inherited(base) ⇒ Object 



91
92
93
94
95
96
 
# File 'lib/rails/application.rb', line 91

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 



98
99
100
 
# File 'lib/rails/application.rb', line 98

def instance
  super.run_load_hooks!
end

Instance Method Details

#config ⇒ Object

:nodoc:



372
373
374
 
# File 'lib/rails/application.rb', line 372

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

#config=(configuration) ⇒ Object

:nodoc:



376
377
378
 
# File 'lib/rails/application.rb', line 376

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



226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
 
# File 'lib/rails/application.rb', line 226

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.



298
299
300
 
# File 'lib/rails/application.rb', line 298

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

#credentials ⇒ Object

Decrypts the credentials hash as kept in config/credentials.yml.enc. This file is encrypted with the Rails master key, which is either taken from ENV["RAILS_MASTER_KEY"] or from loading config/master.key.



441
442
443
 
# File 'lib/rails/application.rb', line 441

def credentials
  @credentials ||= encrypted("config/credentials.yml.enc")
end

#encrypted(path, key_path: "config/master.key", env_key: "RAILS_MASTER_KEY") ⇒ Object

Shorthand to decrypt any encrypted configurations or files.

For any file added with bin/rails encrypted:edit call read to decrypt the file with the master key. The master key is either stored in config/master.key or ENV["RAILS_MASTER_KEY"].

Rails.application.encrypted("config/mystery_man.txt.enc").read
# => "We've met before, haven't we?"

It’s also possible to interpret encrypted YAML files with config.

Rails.application.encrypted("config/credentials.yml.enc").config
# => { next_guys_line: "I don't think so. Where was it you think we met?" }

Any top-level configs are also accessible directly on the return value:

Rails.application.encrypted("config/credentials.yml.enc").next_guys_line
# => "I don't think so. Where was it you think we met?"

The files or configs can also be encrypted with a custom key. To decrypt with a key in the ENV, use:

Rails.application.encrypted("config/special_tokens.yml.enc", env_key: "SPECIAL_TOKENS")

Or to decrypt with a file, that should be version control ignored, relative to Rails.root:

Rails.application.encrypted("config/special_tokens.yml.enc", key_path: "config/special_tokens.key")



472
473
474
475
476
477
478
479
 
# File 'lib/rails/application.rb', line 472

def encrypted(path, key_path: "config/master.key", env_key: "RAILS_MASTER_KEY")
  ActiveSupport::EncryptedConfiguration.new(
    config_path: Rails.root.join(path),
    key_path: Rails.root.join(key_path),
    env_key: env_key,
    raise_if_missing_key: config.require_master_key
  )
end

#env_config ⇒ Object

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



247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
 
# File 'lib/rails/application.rb', line 247

def env_config
  @app_env_config ||= begin
    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" => 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.authenticated_encrypted_cookie_salt" => config.action_dispatch.authenticated_encrypted_cookie_salt,
      "action_dispatch.use_authenticated_cookie_encryption" => config.action_dispatch.use_authenticated_cookie_encryption,
      "action_dispatch.encrypted_cookie_cipher" => config.action_dispatch.encrypted_cookie_cipher,
      "action_dispatch.signed_cookie_digest" => config.action_dispatch.signed_cookie_digest,
      "action_dispatch.cookies_serializer" => config.action_dispatch.cookies_serializer,
      "action_dispatch.cookies_digest" => config.action_dispatch.cookies_digest,
      "action_dispatch.cookies_rotations" => config.action_dispatch.cookies_rotations,
      "action_dispatch.content_security_policy" => config.content_security_policy,
      "action_dispatch.content_security_policy_report_only" => config.content_security_policy_report_only,
      "action_dispatch.content_security_policy_nonce_generator" => config.content_security_policy_nonce_generator
    )
  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.



304
305
306
 
# File 'lib/rails/application.rb', line 304

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

#helpers_paths ⇒ Object

:nodoc:



485
486
487
 
# File 'lib/rails/application.rb', line 485

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



359
360
361
362
363
364
 
# File 'lib/rails/application.rb', line 359

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) 


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

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.



286
287
288
 
# File 'lib/rails/application.rb', line 286

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

#initializers ⇒ Object

:nodoc:



366
367
368
369
370
 
# File 'lib/rails/application.rb', line 366

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.



309
310
311
 
# File 'lib/rails/application.rb', line 309

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

#key_generator ⇒ Object

Returns the application’s KeyGenerator



172
173
174
175
176
177
178
179
180
181
182
183
 
# File 'lib/rails/application.rb', line 172

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 secret_key_base
      ActiveSupport::CachingKeyGenerator.new(
        ActiveSupport::KeyGenerator.new(secret_key_base, iterations: 1000)
      )
    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.



203
204
205
206
207
208
 
# File 'lib/rails/application.rb', line 203

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.



505
506
507
 
# File 'lib/rails/application.rb', line 505

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.



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

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

#reload_routes! ⇒ Object

Reload application routes regardless if they changed or not.



167
168
169
 
# File 'lib/rails/application.rb', line 167

def reload_routes!
  routes_reloader.reload!
end

#require_environment! ⇒ Object

:nodoc:



335
336
337
338
 
# File 'lib/rails/application.rb', line 335

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

#routes_reloader ⇒ Object

:nodoc:



340
341
342
 
# File 'lib/rails/application.rb', line 340

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

#run_load_hooks! ⇒ Object

:nodoc:



152
153
154
155
156
157
158
159
160
161
162
163
164
 
# File 'lib/rails/application.rb', line 152

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.



292
293
294
 
# File 'lib/rails/application.rb', line 292

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

#secret_key_base ⇒ Object

The secret_key_base is used as the input secret to the application’s key generator, which in turn is used to create all MessageVerifiers/MessageEncryptors, including the ones that sign and encrypt cookies.

In test and development, this is simply derived as a MD5 hash of the application’s name.

In all other environments, we look for it first in ENV, then credentials.secret_key_base, and finally secrets.secret_key_base. For most applications, the correct place to store it is in the encrypted credentials file.



428
429
430
431
432
433
434
435
436
 
# File 'lib/rails/application.rb', line 428

def secret_key_base
  if Rails.env.test? || Rails.env.development?
    Digest::MD5.hexdigest self.class.name
  else
    validate_secret_key_base(
      ENV["SECRET_KEY_BASE"] || credentials.secret_key_base || secrets.secret_key_base
    )
  end
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.



394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
 
# File 'lib/rails/application.rb', line 394

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

    if secrets.secret_token.present?
      ActiveSupport::Deprecation.warn(
        "`secrets.secret_token` is deprecated in favor of `secret_key_base` and will be removed in Rails 6.0."
      )
    end

    secrets
  end
end

#secrets=(secrets) ⇒ Object

:nodoc:



416
417
418
 
# File 'lib/rails/application.rb', line 416

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

#to_app ⇒ Object

:nodoc:



481
482
483
 
# File 'lib/rails/application.rb', line 481

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.



347
348
349
350
351
352
353
354
355
 
# File 'lib/rails/application.rb', line 347

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