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class Rails::Application
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.
Attributes
Public Class Methods
# File railties/lib/rails/application.rb, line 98
def create(initial_variable_values = {}, &block)
new(initial_variable_values, &block).run_load_hooks!
end
# File railties/lib/rails/application.rb, line 102
def find_root(from)
find_root_with_flag "config.ru", from, Dir.pwd
end
# File railties/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
# File railties/lib/rails/application.rb, line 94
def instance
super.run_load_hooks!
end
# File railties/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
Public Instance Methods
# File railties/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
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
# File railties/lib/rails/application.rb, line 290
def console(&blk)
self.class.console(&blk)
end
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 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
Stores some of the Rails initial environment parameters which will be used by middlewares and engines to configure themselves.
# File railties/lib/rails/application.rb, line 296
def generators(&blk)
self.class.generators(&blk)
end
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 144
def initialized?
@initialized
end
Returns true if the application is initialized.
# File railties/lib/rails/application.rb, line 278
def initializer(name, opts = {}, &block)
self.class.initializer(name, opts, &block)
end
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 301
def isolate_namespace(mod)
self.class.isolate_namespace(mod)
end
Sends the isolate_namespace
method up to the class method.
# File railties/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
Returns the application's KeyGenerator
# File railties/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
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 271
def rake_tasks(&block)
self.class.rake_tasks(&block)
end
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 163
def reload_routes!
routes_reloader.reload!
end
Reload application routes regardless if they changed or not.
# File railties/lib/rails/application.rb, line 284
def runner(&blk)
self.class.runner(&blk)
end
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 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
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.
© 2004–2018 David Heinemeier Hansson
Licensed under the MIT License.