diff options
Diffstat (limited to 'guides/source/initialization.textile')
| -rw-r--r-- | guides/source/initialization.textile | 159 |
1 files changed, 93 insertions, 66 deletions
diff --git a/guides/source/initialization.textile b/guides/source/initialization.textile index 12b2eb7458..48d4373afe 100644 --- a/guides/source/initialization.textile +++ b/guides/source/initialization.textile @@ -57,7 +57,7 @@ else end </ruby> -The +rbconfig+ file from the Ruby standard library provides us with the +RbConfig+ class which contains detailed information about the Ruby environment, including how Ruby was compiled. We can see thisin use in +railties/lib/rails/script_rails_loader+. +The +rbconfig+ file from the Ruby standard library provides us with the +RbConfig+ class which contains detailed information about the Ruby environment, including how Ruby was compiled. We can see this in use in +railties/lib/rails/script_rails_loader+. <ruby> require 'pathname' @@ -157,11 +157,11 @@ The gems that a Rails 4 application depends on are as follows: TODO: change these when the Rails 4 release is near. * abstract (1.0.0) -* actionmailer (3.1.0.beta) -* actionpack (3.1.0.beta) -* activemodel (3.1.0.beta) -* activerecord (3.1.0.beta) -* activesupport (3.1.0.beta) +* actionmailer (4.0.0.beta) +* actionpack (4.0.0.beta) +* activemodel (4.0.0.beta) +* activerecord (4.0.0.beta) +* activesupport (4.0.0.beta) * arel (2.0.7) * builder (3.0.0) * bundler (1.0.6) @@ -174,8 +174,8 @@ TODO: change these when the Rails 4 release is near. * rack-cache (0.5.3) * rack-mount (0.6.13) * rack-test (0.5.6) -* rails (3.1.0.beta) -* railties (3.1.0.beta) +* rails (4.0.0.beta) +* railties (4.0.0.beta) * rake (0.8.7) * sqlite3-ruby (1.3.2) * thor (0.14.6) @@ -191,6 +191,7 @@ ARGV << '--help' if ARGV.empty? aliases = { "g" => "generate", + "d" => "destroy", "c" => "console", "s" => "server", "db" => "dbconsole", @@ -531,6 +532,7 @@ require "rails" action_controller action_mailer rails/test_unit + sprockets/rails ).each do |framework| begin require "#{framework}/railtie" @@ -543,13 +545,19 @@ First off the line is the +rails+ require itself. h4. +railties/lib/rails.rb+ -This file is responsible for the initial definition of the +Rails+ module and, rather than defining the autoloads like +ActiveSupport+, +ActionDispatch+ and so on, it actually defines other functionality. Such as the +root+, +env+ and +application+ methods which are extremely useful in Rails 3 applications. +This file is responsible for the initial definition of the +Rails+ +module and, rather than defining the autoloads like +ActiveSupport+, ++ActionDispatch+ and so on, it actually defines other functionality. +Such as the +root+, +env+ and +application+ methods which are extremely +useful in Rails 4 applications. However, before all that takes place the +rails/ruby_version_check+ file is required first. h4. +railties/lib/rails/ruby_version_check.rb+ -This file simply checks if the Ruby version is less than 1.8.7 or is 1.9.1 and raises an error if that is the case. Rails 3 simply will not run on earlier versions of Ruby than 1.8.7 or 1.9.1. +This file simply checks if the Ruby version is less than 1.9.3 and +raises an error if that is the case. Rails 4 simply will not run on +earlier versions of Ruby. NOTE: You should always endeavor to run the latest version of Ruby with your Rails applications. The benefits are many, including security fixes and the like, and very often there is a speed increase associated with it. The caveat is that you could have code that potentially breaks on the latest version, which should be fixed to work on the latest version rather than kept around as an excuse not to upgrade. @@ -565,35 +573,28 @@ end These methods can be used to silence STDERR responses and the +silence_stream+ allows you to also silence other streams. Additionally, this mixin allows you to suppress exceptions and capture streams. For more information see the "Silencing Warnings, Streams, and Exceptions":active_support_core_extensions.html#silencing-warnings-streams-and-exceptions section from the Active Support Core Extensions Guide. -h4. +active_support/core_ext/logger.rb+ +h4. +active_support/core_ext/array/extract_options.rb+ -The next file that is required is another Active Support core extension, this time to the +Logger+ class. This begins by defining the +around_[level]+ helpers for the +Logger+ class as well as other methods such as a +datetime_format+ getter and setter for the +formatter+ object tied to a +Logger+ object. - -For more information see the "Extensions to Logger":active_support_core_extensions.html#extensions-to-logger section from the Active Support Core Extensions Guide. +The next file that is required is another Active Support core extension, +this time to the +Array+ and +Hash+ classes. This file defines an ++extract_options!+ method which Rails uses to extract options from +parameters. h4. +railties/lib/rails/application.rb+ -The next file required by +railties/lib/rails.rb+ is +application.rb+. This file defines the +Rails::Application+ constant which the application's class defined in +config/application.rb+ in a standard Rails application depends on. Before the +Rails::Application+ class is defined however, there's some other files that get required first. - -The first of these is +active_support/core_ext/hash/reverse_merge+ which can be "read about in the Active Support Core Extensions guide":active_support_core_extensions.html#merging under the "Merging" section. - -h4. +active_support/file_update_checker.rb+ - -The +ActiveSupport::FileUpdateChecker+ class defined within this file is responsible for checking if a file has been updated since it was last checked. This is used for monitoring the routes file for changes during development environment runs. +The next file required by +railties/lib/rails.rb+ is +application.rb+. +This file defines the +Rails::Application+ constant which the +application's class defined in +config/application.rb+ in a standard +Rails application depends on. -h4. +railties/lib/rails/plugin.rb+ - -This file defines +Rails::Plugin+ which inherits from +Rails::Engine+. Unlike +Rails::Engine+ and +Rails::Railtie+ however, this class is not designed to be inherited from. Instead, this is used simply for loading plugins from within an application and an engine. - -This file begins by requiring +rails/engine.rb+ - -h4. +railties/lib/rails/engine.rb+ +Before the +Rails::Application+ class is +defined however, +rails/engine+ is also loaded, which is responsible for +handling the behavior and definitions of Rails engines. -The +rails/engine.rb+ file defines the +Rails::Engine+ class which inherits from +Rails::Railtie+. The +Rails::Engine+ class defines much of the functionality found within a standard application class such as the +routes+ and +config+ methods. +TIP: You can read more about engines in the "Getting Started with Engines":engines.html guide. -The "API documentation":http://api.rubyonrails.org/classes/Rails/Engine.html for +Rails::Engine+ explains the function of this class pretty well. - -This file's first line requires +rails/railtie.rb+. +Among other things, Rails Engine is also responsible for loading the +Railtie class. h4. +railties/lib/rails/railtie.rb+ @@ -655,7 +656,7 @@ h4. +activesupport/lib/active_support/deprecation/proxy_wrappers.rb+ +proxy_wrappers.rb+ defines deprecation wrappers for methods, instance variables and constants. Previously, this was used for the +RAILS_ENV+ and +RAILS_ROOT+ constants for 3.0 but since then these constants have been removed. The deprecation message that would be raised from these would be something like: <plain> - BadConstant is deprecated! Use GoodConstant instead. +BadConstant is deprecated! Use GoodConstant instead. </plain> h4. +active_support/ordered_options+ @@ -664,7 +665,30 @@ This file is the next file required from +rails/configuration.rb+ is the file th The next file required is +active_support/core_ext/hash/deep_dup+ which is covered in "Active Support Core Extensions guide":active_support_core_extensions.html#deep_dup -The file that is required next from is +rails/paths+ +h4. +active_support/core_ext/object+ + +This file is responsible for requiring many more Active Support core extensions: + +<ruby> +require 'active_support/core_ext/object/acts_like' +require 'active_support/core_ext/object/blank' +require 'active_support/core_ext/object/duplicable' +require 'active_support/core_ext/object/deep_dup' +require 'active_support/core_ext/object/try' +require 'active_support/core_ext/object/inclusion' + +require 'active_support/core_ext/object/conversions' +require 'active_support/core_ext/object/instance_variables' + +require 'active_support/core_ext/object/to_json' +require 'active_support/core_ext/object/to_param' +require 'active_support/core_ext/object/to_query' +require 'active_support/core_ext/object/with_options' +</ruby> + +The Rails API documentation covers them in great detail, so we're not going to explain each of them. + +The file that is required next from +rails/configuration+ is +rails/paths+. h4. +railties/lib/rails/paths.rb+ @@ -680,7 +704,6 @@ module Rails autoload :Debugger, "rails/rack/debugger" autoload :Logger, "rails/rack/logger" autoload :LogTailer, "rails/rack/log_tailer" - autoload :Static, "rails/rack/static" end end </ruby> @@ -706,9 +729,23 @@ h4. +active_support/inflections+ This file references the +ActiveSupport::Inflector+ constant which isn't loaded by this point. But there were autoloads set up in +activesupport/lib/active_support.rb+ which will load the file which loads this constant and so then it will be defined. Then this file defines pluralization and singularization rules for words in Rails. This is how Rails knows how to pluralize "tomato" to "tomatoes". +<ruby> +inflect.irregular('zombie', 'zombies') +</ruby> + h4. +activesupport/lib/active_support/inflector/transliterate.rb+ -In this file is where the "+transliterate+":http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html#method-i-transliterate and +parameterize+:http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html#method-i-parameterize methods are defined. The documentation for both of these methods is very much worth reading. +This is the file that defines the "+transliterate+":http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html#method-i-transliterate and "+parameterize+":http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html#method-i-parameterize methods. + +h4. +active_support/core_ext/module/introspection+ + +The next file loaded by +rails/railtie+ is the introspection core +extension, which extends +Module+ with methods like +parent_name+, +parent+ and ++parents+. + +h4. +active_support/core_ext/module/delegation+ + +The final file loaded by +rails/railtie+ is the delegation core extension, which defines the "+delegate+":http://api.rubyonrails.org/classes/Module.html#method-i-delegate method. h4. Back to +railties/lib/rails/railtie.rb+ @@ -888,7 +925,7 @@ The +initializers_chain+ method referenced in the +initializers_for+ method is d <ruby> def initializers_chain initializers = Collection.new - ancestors.reverse_each do | klass | + ancestors.reverse_each do |klass| next unless klass.respond_to?(:initializers) initializers = initializers + klass.initializers end @@ -951,46 +988,35 @@ This file defines the +ActiveSupport::Railtie+ constant which like the +I18n::Ra Then this Railtie sets up three more initializers: -* +active_support.initialize_whiny_nils+ * +active_support.deprecation_behavior+ * +active_support.initialize_time_zone+ +* +active_support.set_configs+ We will cover what each of these initializers do when they run. Once the +active_support/railtie+ file has finished loading the next file required from +railties/lib/rails.rb+ is the +action_dispatch/railtie+. -h4. +activesupport/lib/action_dispatch/railtie.rb+ +h4. +actionpack/lib/action_dispatch/railtie.rb+ This file defines the +ActionDispatch::Railtie+ class, but not before requiring +action_dispatch+. -h4. +activesupport/lib/action_dispatch.rb+ - -This file attempts to locate the +active_support+ and +active_model+ libraries by looking a couple of directories back from the current file and then adds the +active_support+ and +active_model+ +lib+ directories to the load path, but only if they aren't already, which they are. - -<ruby> -activesupport_path = File.expand_path('../../../activesupport/lib', __FILE__) -$:.unshift(activesupport_path) if File.directory?(activesupport_path) && !$:.include?(activesupport_path) - -activemodel_path = File.expand_path('../../../activemodel/lib', __FILE__) -$:.unshift(activemodel_path) if File.directory?(activemodel_path) && !$:.include?(activemodel_path) -</ruby> - -In effect, these lines only define the +activesupport_path+ and +activemodel_path+ variables and nothing more. +h4. +actionpack/lib/action_dispatch.rb+ -The next two requires in this file are already done, so they are not run: +This file starts off with the following requires: <ruby> require 'active_support' require 'active_support/dependencies/autoload' +require 'active_support/core_ext/module/attribute_accessors' </ruby> -The following require is to +action_pack+ (+activesupport/lib/action_pack.rb+) which has a 22-line copyright notice at the top of it and ends in a simple require to +action_pack/version+. This file, like other +version.rb+ files before it, defines the +ActionPack::VERSION+ constant: +The following require is to +action_pack+ (+actionpack/lib/action_pack.rb+) which contains a simple require to +action_pack/version+. This file, like other +version.rb+ files before it, defines the +ActionPack::VERSION+ constant: <ruby> module ActionPack module VERSION #:nodoc: - MAJOR = 3 - MINOR = 1 + MAJOR = 4 + MINOR = 0 TINY = 0 PRE = "beta" @@ -1008,8 +1034,8 @@ This file makes a require to +active_model/version+ which defines the version fo <ruby> module ActiveModel module VERSION #:nodoc: - MAJOR = 3 - MINOR = 1 + MAJOR = 4 + MINOR = 0 TINY = 0 PRE = "beta" @@ -1046,7 +1072,7 @@ Once it has finished loading, the +I18n.load_path+ method is used to add the +ac The loading of this file finishes the loading of +active_model+ and so we go back to +action_dispatch+. -h4. Back to +activesupport/lib/action_dispatch.rb+ +h4. Back to +actionpack/lib/action_dispatch.rb+ The remainder of this file requires the +rack+ file from the Rack gem which defines the +Rack+ module. After +rack+, there's autoloads defined for the +Rack+, +ActionDispatch+, +ActionDispatch::Http+, +ActionDispatch::Session+. A new method called +autoload_under+ is used here, and this simply prefixes the files where the modules are autoloaded from with the path specified. For example here: @@ -1060,7 +1086,7 @@ The +Assertions+ module is in the +action_dispatch/testing+ folder rather than s Finally, this file defines a top-level autoload, the +Mime+ constant. -h4. Back to +activesupport/lib/action_dispatch/railtie.rb+ +h4. Back to +actionpack/lib/action_dispatch/railtie.rb+ After +action_dispatch+ is required in this file, the +ActionDispatch::Railtie+ class is defined and is yet another class that inherits from +Rails::Railtie+. This class defines some initial configuration option defaults for +config.action_dispatch+ before setting up a single initializer called +action_dispatch.configure+. @@ -1082,22 +1108,21 @@ h4. +activerecord/lib/active_record.rb+ This file begins by detecting if the +lib+ directories of +active_support+ and +active_model+ are not in the load path and if they aren't then adds them. As we saw back in +action_dispatch.rb+, these directories are already there. -The first three requires have already been done by other files and so aren't loaded here, but the 4th require, the one to +arel+ will require the file provided by the Arel gem, which defines the +Arel+ module. +The first couple of requires have already been done by other files and so aren't loaded here, but the next one to +arel+ will require the file provided by the Arel gem, which defines the +Arel+ module. <ruby> require 'active_support' -require 'active_support/i18n' require 'active_model' require 'arel' </ruby> -The 5th require in this file is one to +active_record/version+ which defines the +ActiveRecord::VERSION+ constant: +The file required next is +active_record/version+ which defines the +ActiveRecord::VERSION+ constant: <ruby> module ActiveRecord module VERSION #:nodoc: - MAJOR = 3 - MINOR = 1 + MAJOR = 4 + MINOR = 0 TINY = 0 PRE = "beta" @@ -1121,7 +1146,9 @@ This will set the engine for +Arel::Table+ to be +ActiveRecord::Base+. The file then finishes with this line: <ruby> -I18n.load_path << File.dirname(__FILE__) + '/active_record/locale/en.yml' +ActiveSupport.on_load(:i18n) do + I18n.load_path << File.dirname(__FILE__) + '/active_record/locale/en.yml' +end </ruby> This will add the translations from +activerecord/lib/active_record/locale/en.yml+ to the load path for +I18n+, with this file being parsed when all the translations are loaded. |