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Merge branch 'master' of github.com:lifo/docrails

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This commit is contained in:
Vijay Dev 2012-06-14 22:52:38 +05:30
commit c1474ff2e7
16 changed files with 297 additions and 766 deletions
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18
actionpack/lib/action_controller/metal/http_authentication.rb
View file

@ -401,16 +401,20 @@ module ActionController
end
end
# If token Authorization header is present, call the login procedure with
# the present token and options.
# If token Authorization header is present, call the login
# procedure with the present token and options.
#
# [controller]
# ActionController::Base instance for the current request.
#
# [login_procedure]
# Proc to call if a token is present. The Proc should take two arguments:
#
# controller - ActionController::Base instance for the current request.
# login_procedure - Proc to call if a token is present. The Proc should
# take 2 arguments:
# authenticate(controller) { |token, options| ... }
#
# Returns the return value of `&login_procedure` if a token is found.
# Returns nil if no token is found.
# Returns the return value of <tt>login_procedure</tt> if a
# token is found. Returns <tt>nil</tt> if no token is found.
def authenticate(controller, &login_procedure)
token, options = token_and_options(controller.request)
unless token.blank?

14
actionpack/lib/action_controller/metal/request_forgery_protection.rb
View file

@ -14,6 +14,20 @@ module ActionController #:nodoc:
# authentication scheme there anyway). Also, GET requests are not protected as these
# should be idempotent.
#
# It's important to remember that XML or JSON requests are also affected and if
# you're building an API you'll need something like:
#
# class ApplicationController < ActionController::Base
# protect_from_forgery
# skip_before_filter :verify_authenticity_token, :if => :json_request?
#
# protected
#
# def json_request?
# request.format.json?
# end
# end
#
# CSRF protection is turned on with the <tt>protect_from_forgery</tt> method,
# which checks the token and resets the session if it doesn't match what was expected.
# A call to this method is generated for new \Rails applications by default.

16
activemodel/lib/active_model/observer_array.rb
View file

@ -17,6 +17,11 @@ module ActiveModel
# Disables one or more observers. This supports multiple forms:
#
# ORM.observers.disable :all
# # => disables all observers for all models subclassed from
# # an ORM base class that includes ActiveModel::Observing
# # e.g. ActiveRecord::Base
#
# ORM.observers.disable :user_observer
# # => disables the UserObserver
#
@ -27,9 +32,6 @@ module ActiveModel
# ORM.observers.disable :observer_1, :observer_2
# # => disables Observer1 and Observer2 for all models.
#
# ORM.observers.disable :all
# # => disables all observers for all models.
#
# User.observers.disable :all do
# # all user observers are disabled for
# # just the duration of the block
@ -40,6 +42,11 @@ module ActiveModel
# Enables one or more observers. This supports multiple forms:
#
# ORM.observers.enable :all
# # => enables all observers for all models subclassed from
# # an ORM base class that includes ActiveModel::Observing
# # e.g. ActiveRecord::Base
#
# ORM.observers.enable :user_observer
# # => enables the UserObserver
#
@ -51,9 +58,6 @@ module ActiveModel
# ORM.observers.enable :observer_1, :observer_2
# # => enables Observer1 and Observer2 for all models.
#
# ORM.observers.enable :all
# # => enables all observers for all models.
#
# User.observers.enable :all do
# # all user observers are enabled for
# # just the duration of the block

3
activemodel/lib/active_model/validations/exclusion.rb
View file

@ -30,8 +30,7 @@ module ActiveModel
# * <tt>:in</tt> - An enumerable object of items that the value shouldn't be
# part of. This can be supplied as a proc or lambda which returns an
# enumerable. If the enumerable is a range the test is performed with
# <tt>Range#cover?</tt> (backported in Active Support for 1.8), otherwise
# with <tt>include?</tt>.
# <tt>Range#cover?</tt>, otherwise with <tt>include?</tt>.
# * <tt>:message</tt> - Specifies a custom error message (default is: "is
# reserved").
# * <tt>:allow_nil</tt> - If set to true, skips this validation if the attribute

4
activemodel/lib/active_model/validations/inclusion.rb
View file

@ -28,8 +28,8 @@ module ActiveModel
# Configuration options:
# * <tt>:in</tt> - An enumerable object of available items. This can be
# supplied as a proc or lambda which returns an enumerable. If the enumerable
# is a range the test is performed with <tt>Range#cover?</tt>
# (backported in Active Support for 1.8), otherwise with <tt>include?</tt>.
# is a range the test is performed with <tt>Range#cover?</tt>, otherwise with
# <tt>include?</tt>.
# * <tt>:message</tt> - Specifies a custom error message (default is: "is not
# included in the list").
# * <tt>:allow_nil</tt> - If set to true, skips this validation if the attribute

2
activerecord/lib/active_record/store.rb
View file

@ -2,7 +2,7 @@ require 'active_support/core_ext/hash/indifferent_access'
module ActiveRecord
# Store gives you a thin wrapper around serialize for the purpose of storing hashes in a single column.
# It's like a simple key/value store backed into your record when you don't care about being able to
# It's like a simple key/value store baked into your record when you don't care about being able to
# query that store outside the context of a single record.
#
# You can then declare accessors to this store that are then accessible just like any other attribute

6
activesupport/lib/active_support/core_ext/object/try.rb
View file

@ -11,8 +11,6 @@ class Object
# subclasses of +BasicObject+. For example, using try with +SimpleDelegator+ will
# delegate +try+ to target instead of calling it on delegator itself.
#
# ==== Examples
#
# Without +try+
# @person && @person.name
# or
@ -27,7 +25,7 @@ class Object
#
# Without a method argument try will yield to the block unless the receiver is nil.
# @person.try { |p| "#{p.first_name} #{p.last_name}" }
#--
#
# +try+ behaves like +Object#public_send+, unless called on +NilClass+.
def try(*a, &b)
if a.empty? && block_given?
@ -42,8 +40,6 @@ class NilClass
# Calling +try+ on +nil+ always returns +nil+.
# It becomes specially helpful when navigating through associations that may return +nil+.
#
# === Examples
#
# nil.try(:name) # => nil
#
# Without +try+

9
activesupport/lib/active_support/gzip.rb
View file

@ -2,7 +2,14 @@ require 'zlib'
require 'stringio'
module ActiveSupport
# A convenient wrapper for the zlib standard library that allows compression/decompression of strings with gzip.
# A convenient wrapper for the zlib standard library that allows
# compression/decompression of strings with gzip.
#
# gzip = ActiveSupport::Gzip.compress('compress me!')
# # => "\x1F\x8B\b\x00o\x8D\xCDO\x00\x03K\xCE\xCF-(J-.V\xC8MU\x04\x00R>n\x83\f\x00\x00\x00"
#
# ActiveSupport::Gzip.decompress(gzip)
# # => "compress me!"
module Gzip
class Stream < StringIO
def initialize(*)

8
activesupport/lib/active_support/json/decoding.rb
View file

@ -39,6 +39,14 @@ module ActiveSupport
self.backend = old_backend
end
# Returns the class of the error that will be raised when there is an error in decoding JSON.
# Using this method means you won't directly depend on the ActiveSupport's JSON implementation, in case it changes in the future.
#
# begin
# obj = ActiveSupport::JSON.decode(some_string)
# rescue ActiveSupport::JSON.parse_error
# Rails.logger.warn("Attempted to decode invalid JSON: #{some_string}")
# end
def parse_error
MultiJson::DecodeError
end

113
activesupport/lib/active_support/number_helper.rb
View file

@ -27,13 +27,13 @@ module ActiveSupport
# number_to_phone(5551234) # => 555-1234
# number_to_phone("5551234") # => 555-1234
# number_to_phone(1235551234) # => 123-555-1234
# number_to_phone(1235551234, :area_code => true) # => (123) 555-1234
# number_to_phone(1235551234, :delimiter => " ") # => 123 555 1234
# number_to_phone(1235551234, :area_code => true, :extension => 555) # => (123) 555-1234 x 555
# number_to_phone(1235551234, :country_code => 1) # => +1-123-555-1234
# number_to_phone(1235551234, area_code: true) # => (123) 555-1234
# number_to_phone(1235551234, delimiter: ' ') # => 123 555 1234
# number_to_phone(1235551234, area_code: true, extension: 555) # => (123) 555-1234 x 555
# number_to_phone(1235551234, country_code: 1) # => +1-123-555-1234
# number_to_phone("123a456") # => 123a456
#
# number_to_phone(1235551234, :country_code => 1, :extension => 1343, :delimiter => ".")
# number_to_phone(1235551234, country_code: 1, extension: 1343, delimiter: '.')
# # => +1.123.555.1234 x 1343
def number_to_phone(number, options = {})
return unless number
@ -87,15 +87,15 @@ module ActiveSupport
#
# number_to_currency(1234567890.50) # => $1,234,567,890.50
# number_to_currency(1234567890.506) # => $1,234,567,890.51
# number_to_currency(1234567890.506, :precision => 3) # => $1,234,567,890.506
# number_to_currency(1234567890.506, :locale => :fr) # => 1 234 567 890,51 €
# number_to_currency("123a456") # => $123a456
# number_to_currency(1234567890.506, precision: 3) # => $1,234,567,890.506
# number_to_currency(1234567890.506, locale: :fr) # => 1 234 567 890,51 €
# number_to_currency('123a456') # => $123a456
#
# number_to_currency(-1234567890.50, :negative_format => "(%u%n)")
# number_to_currency(-1234567890.50, negative_format: '(%u%n)')
# # => ($1,234,567,890.50)
# number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "")
# number_to_currency(1234567890.50, unit: '&pound;', separator: ',', delimiter: '')
# # => &pound;1234567890,50
# number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "", :format => "%n %u")
# number_to_currency(1234567890.50, unit: '&pound;', separator: ',', delimiter: '', format: '%n %u')
# # => 1234567890,50 &pound;
def number_to_currency(number, options = {})
return unless number
@ -145,14 +145,13 @@ module ActiveSupport
# ==== Examples
#
# number_to_percentage(100) # => 100.000%
# number_to_percentage("98") # => 98.000%
# number_to_percentage(100, :precision => 0) # => 100%
# number_to_percentage(1000, :delimiter => '.', :separator => ',') # => 1.000,000%
# number_to_percentage(302.24398923423, :precision => 5) # => 302.24399%
# number_to_percentage('98') # => 98.000%
# number_to_percentage(100, precision: 0) # => 100%
# number_to_percentage(1000, delimiter: '.', separator: ,') # => 1.000,000%
# number_to_percentage(302.24398923423, precision: 5) # => 302.24399%
# number_to_percentage(1000, :locale => :fr) # => 1 000,000%
# number_to_percentage("98a") # => 98a%
# number_to_percentage(100, :format => "%n %") # => 100 %
#
# number_to_percentage('98a') # => 98a%
# number_to_percentage(100, format: '%n %') # => 100 %
def number_to_percentage(number, options = {})
return unless number
options = options.symbolize_keys
@ -182,14 +181,14 @@ module ActiveSupport
# ==== Examples
#
# number_to_delimited(12345678) # => 12,345,678
# number_to_delimited("123456") # => 123,456
# number_to_delimited('123456') # => 123,456
# number_to_delimited(12345678.05) # => 12,345,678.05
# number_to_delimited(12345678, :delimiter => ".") # => 12.345.678
# number_to_delimited(12345678, :delimiter => ",") # => 12,345,678
# number_to_delimited(12345678.05, :separator => " ") # => 12,345,678 05
# number_to_delimited(12345678.05, :locale => :fr) # => 12 345 678,05
# number_to_delimited("112a") # => 112a
# number_to_delimited(98765432.98, :delimiter => " ", :separator => ",")
# number_to_delimited(12345678, delimiter: '.') # => 12.345.678
# number_to_delimited(12345678, delimiter: ',') # => 12,345,678
# number_to_delimited(12345678.05, separator: ' ') # => 12,345,678 05
# number_to_delimited(12345678.05, locale: :fr) # => 12 345 678,05
# number_to_delimited('112a') # => 112a
# number_to_delimited(98765432.98, delimiter: ' ', separator: ',')
# # => 98 765 432,98
def number_to_delimited(number, options = {})
options = options.symbolize_keys
@ -228,19 +227,19 @@ module ActiveSupport
# ==== Examples
#
# number_to_rounded(111.2345) # => 111.235
# number_to_rounded(111.2345, :precision => 2) # => 111.23
# number_to_rounded(13, :precision => 5) # => 13.00000
# number_to_rounded(389.32314, :precision => 0) # => 389
# number_to_rounded(111.2345, :significant => true) # => 111
# number_to_rounded(111.2345, :precision => 1, :significant => true) # => 100
# number_to_rounded(13, :precision => 5, :significant => true) # => 13.000
# number_to_rounded(111.234, :locale => :fr) # => 111,234
# number_to_rounded(111.2345, precision: 2) # => 111.23
# number_to_rounded(13, precision: 5) # => 13.00000
# number_to_rounded(389.32314, precision: 0) # => 389
# number_to_rounded(111.2345, significant: true) # => 111
# number_to_rounded(111.2345, precision: 1, significant: true) # => 100
# number_to_rounded(13, precision: 5, significant: true) # => 13.000
# number_to_rounded(111.234, locale: :fr) # => 111,234
#
# number_to_rounded(13, :precision => 5, :significant => true, :strip_insignificant_zeros => true)
# number_to_rounded(13, precision: 5, significant: true, strip_insignificant_zeros: true)
# # => 13
#
# number_to_rounded(389.32314, :precision => 4, :significant => true) # => 389.3
# number_to_rounded(1111.2345, :precision => 2, :separator => ',', :delimiter => '.')
# number_to_rounded(389.32314, precision: 4, significant: true) # => 389.3
# number_to_rounded(1111.2345, precision: 2, separator: ',', delimiter: '.')
# # => 1.111,23
def number_to_rounded(number, options = {})
options = options.symbolize_keys
@ -315,15 +314,15 @@ module ActiveSupport
# number_to_human_size(1234567) # => 1.18 MB
# number_to_human_size(1234567890) # => 1.15 GB
# number_to_human_size(1234567890123) # => 1.12 TB
# number_to_human_size(1234567, :precision => 2) # => 1.2 MB
# number_to_human_size(483989, :precision => 2) # => 470 KB
# number_to_human_size(1234567, :precision => 2, :separator => ',') # => 1,2 MB
# number_to_human_size(1234567, precision: 2) # => 1.2 MB
# number_to_human_size(483989, precision: 2) # => 470 KB
# number_to_human_size(1234567, precision: 2, separator: ',') # => 1,2 MB
#
# Non-significant zeros after the fractional separator are
# stripped out by default (set
# <tt>:strip_insignificant_zeros</tt> to +false+ to change that):
# number_to_human_size(1234567890123, :precision => 5) # => "1.1229 TB"
# number_to_human_size(524288000, :precision => 5) # => "500 MB"
# Non-significant zeros after the fractional separator are stripped out by
# default (set <tt>:strip_insignificant_zeros</tt> to +false+ to change that):
#
# number_to_human_size(1234567890123, precision: 5) # => "1.1229 TB"
# number_to_human_size(524288000, precision: 5) # => "500 MB"
def number_to_human_size(number, options = {})
options = options.symbolize_keys
@ -415,19 +414,20 @@ module ActiveSupport
# number_to_human(1234567890123) # => "1.23 Trillion"
# number_to_human(1234567890123456) # => "1.23 Quadrillion"
# number_to_human(1234567890123456789) # => "1230 Quadrillion"
# number_to_human(489939, :precision => 2) # => "490 Thousand"
# number_to_human(489939, :precision => 4) # => "489.9 Thousand"
# number_to_human(1234567, :precision => 4,
# :significant => false) # => "1.2346 Million"
# number_to_human(1234567, :precision => 1,
# :separator => ',',
# :significant => false) # => "1,2 Million"
# number_to_human(489939, precision: 2) # => "490 Thousand"
# number_to_human(489939, precision: 4) # => "489.9 Thousand"
# number_to_human(1234567, precision: 4,
# significant: false) # => "1.2346 Million"
# number_to_human(1234567, precision: 1,
# separator: ',',
# significant: false) # => "1,2 Million"
#
# Non-significant zeros after the decimal separator are stripped
# out by default (set <tt>:strip_insignificant_zeros</tt> to
# +false+ to change that):
# number_to_human(12345012345, :significant_digits => 6) # => "12.345 Billion"
# number_to_human(500000000, :precision => 5) # => "500 Million"
#
# number_to_human(12345012345, significant_digits: 6) # => "12.345 Billion"
# number_to_human(500000000, precision: 5) # => "500 Million"
#
# ==== Custom Unit Quantifiers
#
@ -435,6 +435,7 @@ module ActiveSupport
# number_to_human(500000, :units => {:unit => "ml", :thousand => "lt"}) # => "500 lt"
#
# If in your I18n locale you have:
#
# distance:
# centi:
# one: "centimeter"
@ -505,22 +506,22 @@ module ActiveSupport
end
private_class_method :private_module_and_instance_method
def format_translations(namespace, locale)
def format_translations(namespace, locale) #:nodoc:
defaults_translations(locale).merge(translations_for(namespace, locale))
end
private_module_and_instance_method :format_translations
def defaults_translations(locale)
def defaults_translations(locale) #:nodoc:
I18n.translate(:'number.format', :locale => locale, :default => {})
end
private_module_and_instance_method :defaults_translations
def translations_for(namespace, locale)
def translations_for(namespace, locale) #:nodoc:
I18n.translate(:"number.#{namespace}.format", :locale => locale, :default => {})
end
private_module_and_instance_method :translations_for
def valid_float?(number)
def valid_float?(number) #:nodoc:
Float(number)
rescue ArgumentError, TypeError
false

8
guides/source/active_support_core_extensions.textile
View file

@ -1857,6 +1857,7 @@ h4. Formatting
Enables the formatting of numbers in a variety of ways.
Produce a string representation of a number as a telephone number:
<ruby>
5551234.to_s(:phone) # => 555-1234
1235551234.to_s(:phone) # => 123-555-1234
@ -1867,6 +1868,7 @@ Produce a string representation of a number as a telephone number:
</ruby>
Produce a string representation of a number as currency:
<ruby>
1234567890.50.to_s(:currency) # => $1,234,567,890.50
1234567890.506.to_s(:currency) # => $1,234,567,890.51
@ -1874,6 +1876,7 @@ Produce a string representation of a number as currency:
</ruby>
Produce a string representation of a number as a percentage:
<ruby>
100.to_s(:percentage) # => 100.000%
100.to_s(:percentage, :precision => 0) # => 100%
@ -1882,6 +1885,7 @@ Produce a string representation of a number as a percentage:
</ruby>
Produce a string representation of a number in delimited form:
<ruby>
12345678.to_s(:delimited) # => 12,345,678
12345678.05.to_s(:delimited) # => 12,345,678.05
@ -1891,6 +1895,7 @@ Produce a string representation of a number in delimited form:
</ruby>
Produce a string representation of a number rounded to a precision:
<ruby>
111.2345.to_s(:rounded) # => 111.235
111.2345.to_s(:rounded, :precision => 2) # => 111.23
@ -1900,6 +1905,7 @@ Produce a string representation of a number rounded to a precision:
</ruby>
Produce a string representation of a number as a human-readable number of bytes:
<ruby>
123.to_s(:human_size) # => 123 Bytes
1234.to_s(:human_size) # => 1.21 KB
@ -1910,6 +1916,7 @@ Produce a string representation of a number as a human-readable number of bytes:
</ruby>
Produce a string representation of a number in human-readable words:
<ruby>
123.to_s(:human) # => "123"
1234.to_s(:human) # => "1.23 Thousand"
@ -2469,6 +2476,7 @@ To do so, the method loops over the pairs and builds nodes that depend on the _v
* If +value+ responds to +to_xml+ the method is invoked with +key+ as <tt>:root</tt>.
* Otherwise, a node with +key+ as tag is created with a string representation of +value+ as text node. If +value+ is +nil+ an attribute "nil" set to "true" is added. Unless the option <tt>:skip_types</tt> exists and is true, an attribute "type" is added as well according to the following mapping:
<ruby>
XML_TYPE_NAMES = {
"Symbol" => "symbol",

2
guides/source/caching_with_rails.textile
View file

@ -332,7 +332,7 @@ h4. ActiveSupport::Cache::MemoryStore
This cache store keeps entries in memory in the same Ruby process. The cache store has a bounded size specified by the +:size+ options to the initializer (default is 32Mb). When the cache exceeds the allotted size, a cleanup will occur and the least recently used entries will be removed.
<ruby>
config.cache_store = :memory_store, :size => 64.megabytes
config.cache_store = :memory_store, { :size => 64.megabytes }
</ruby>
If you're running multiple Ruby on Rails server processes (which is the case if you're using mongrel_cluster or Phusion Passenger), then your Rails server process instances won't be able to share cache data with each other. This cache store is not appropriate for large application deployments, but can work well for small, low traffic sites with only a couple of server processes or for development and test environments.

4
guides/source/contributing_to_ruby_on_rails.textile
View file

@ -109,7 +109,7 @@ You can run any single test separately too:
<shell>
$ cd actionpack
$ ruby -Itest test/template/form_helper_test.rb
$ bundle exec ruby -Itest test/template/form_helper_test.rb
</shell>
h4. Warnings
@ -319,6 +319,8 @@ Now get busy and add or edit code. You’re on your branch now, so you can write
* Include tests that fail without your code, and pass with it.
* Update the (surrounding) documentation, examples elsewhere, and the guides: whatever is affected by your contribution.
TIP: Changes that are cosmetic in nature and do not add anything substantial to the stability, functionality, or testability of Rails will generally not be accepted.
h4. Follow the Coding Conventions
Rails follows a simple set of coding style conventions.

12
guides/source/form_helpers.textile
View file

@ -419,6 +419,18 @@ TIP: The second argument to +options_for_select+ must be exactly equal to the de
WARNING: when +:inlude_blank+ or +:prompt:+ are not present, +:include_blank+ is forced true if the select attribute +required+ is true, display +size+ is one and +multiple+ is not true.
You can add arbitrary attributes to the options using hashes:
<erb>
<%= options_for_select([['Lisbon', 1, :'data-size' => '2.8 million'], ['Madrid', 2, :'data-size' => '3.2 million']], 2) %>
output:
<option value="1" data-size="2.8 million">Lisbon</option>
<option value="2" selected="selected" data-size="3.2 million">Madrid</option>
...
</erb>
h4. Select Boxes for Dealing with Models
In most cases form controls will be tied to a specific database model and as you might expect Rails provides helpers tailored for that purpose. Consistent with other form helpers, when dealing with models you drop the +_tag+ suffix from +select_tag+:

760
guides/source/initialization.textile
View file

@ -8,14 +8,14 @@ as of Rails 4. It is an extremely in-depth guide and recommended for advanced Ra
endprologue.
This guide goes through every single file, class and method call that is
This guide goes through every method call that is
required to boot up the Ruby on Rails stack for a default Rails 4 application, explaining each part in detail along the way. For this guide, we will be focusing on how the two most common methods (+rails server+ and Passenger) boot a Rails application.
NOTE: Paths in this guide are relative to Rails or a Rails application unless otherwise specified.
h3. Launch!
As of Rails 3, +script/server+ has become +rails server+. This was done to centralize all rails related commands to one common file.
A Rails application is usually started with the command +rails server+.
h4. +bin/rails+
@ -224,47 +224,27 @@ when 'server'
}
</ruby>
This file will change into the root of the directory (a path two directories back from +APP_PATH+ which points at +config/application.rb+), but only if the +config.ru+ file isn't found. This then requires +rails/commands/server+ which requires +action_dispatch+ and sets up the +Rails::Server+ class.
This file will change into the root of the directory (a path two directories back from +APP_PATH+ which points at +config/application.rb+), but only if the +config.ru+ file isn't found. This then requires +rails/commands/server+ which sets up the +Rails::Server+ class.
<ruby>
require 'fileutils'
require 'optparse'
require 'action_dispatch'
module Rails
class Server < ::Rack::Server
</ruby>
+fileutils+ and +optparse+ are standard Ruby libraries which provide helper functions for working with files and parsing options.
h4. +actionpack/lib/action_dispatch.rb+
Action Dispatch is the routing component of the Rails framework. It depends on Active Support, +actionpack/lib/action_pack.rb+ and +Rack+ being available. The first thing required here is +active_support+.
Action Dispatch is the routing component of the Rails framework. Other
than the rouing itself, it adds
functionalities like routing, session, and common middlewares.
h4. +activesupport/lib/active_support.rb+
This file begins with requiring +active_support/lib/active_support/dependencies/autoload.rb+ which redefines Ruby's +autoload+ method to have a little more extra behaviour especially in regards to eager autoloading. Eager autoloading is the loading of all required classes and will happen when the +config.cache_classes+ setting is +true+. The required file also requires another file: +active_support/lazy_load_hooks+
h4. +activesupport/lib/active_support/lazy_load_hooks.rb+
This file defines the +ActiveSupport.on_load+ hook which is used to execute code when specific parts are loaded. We'll see this in use a little later on.
This file begins with requiring +active_support/inflector/methods+.
h4. +activesupport/lib/active_support/inflector/methods.rb+
The +methods.rb+ file is responsible for defining methods such as +camelize+, +underscore+ and +dasherize+ as well as a slew of others. The "+ActiveSupport::Inflector+ documentation":http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html covers them all pretty decently.
In this file there are a lot of lines such as this inside the +ActiveSupport+ module:
<ruby>
autoload :Inflector
</ruby>
Due to the overriding of the +autoload+ method, Ruby will know how to look for this file at +activesupport/lib/active_support/inflector.rb+ when the +Inflector+ class is first referenced.
The +active_support/lib/active_support/version.rb+ that is also required here simply defines an +ActiveSupport::VERSION+ constant which defines a couple of constants inside this module, the main constant of this is +ActiveSupport::VERSION::STRING+ which returns the current version of ActiveSupport.
The +active_support/lib/active_support.rb+ file simply defines the +ActiveSupport+ module and some autoloads (eager and of the normal variety) for it.
h4. +actionpack/lib/action_dispatch.rb+ cont'd.
Now back to +action_pack/lib/action_dispatch.rb+. The next +require+ in this file is one for +action_pack+, which simply calls +action_pack/version.rb+ which defines +ActionPack::VERSION+ and the constants, much like +ActiveSpport+ does.
After this line, there's a require to +active_model+ which simply defines autoloads for the +ActiveModel+ part of Rails and sets up the +ActiveModel+ module which is used later on.
The last of the requires is to +rack+, which like the +active_model+ and +active_support+ requires before it, sets up the +Rack+ module as well as the autoloads for constants within it.
Finally in +action_dispatch.rb+ the +ActionDispatch+ module and *its* autoloads are declared.
Action Dispatch itself is also responsible for loading Active Support, Action
Pack, Active Model, and Rack.
h4. +rails/commands/server.rb+
@ -363,11 +343,21 @@ def parse!(args)
...
</ruby>
This method will set up keys for the +options+ which Rails will then be able to use to determine how its server should run. After +initialize+ has finished, then the +start+ method will launch the server.
This method will set up keys for the +options+ which Rails will then be
able to use to determine how its server should run. After +initialize+
has finished, we jump back into +rails/server+ where +APP_PATH+ (which was
set earlier) is required.
h4. +config/application+
When +require APP_PATH+ is executed, +config/application.rb+ is loaded.
This is a file exists in your app and it's free for you to change based
on your needs. Among other things, inside this file you load gems with
bundler, and create your application namespace.
h4. +Rails::Server#start+
This method is defined like this:
After +congif/application+ is loaded, +server.start+ is called. This method is defined like this:
<ruby>
def start
@ -405,7 +395,7 @@ method creates a trap for +INT+ signals, so if you +CTRL-C+ the server,
it will exit the process. As we can see from the code here, it will
create the +tmp/cache+, +tmp/pids+, +tmp/sessions+ and +tmp/sockets+
directories. It then calls +wrapped_app+ which is responsible for
creating the Rack app, before creating and assignig an
creating the Rack app, before creating and assigning an
instance of +ActiveSupport::Logger+.
The +super+ method will call +Rack::Server.start+ which begins its definition like this:
@ -455,7 +445,8 @@ end
</ruby>
The interesting part for a Rails app is the last line, +server.run+. Here we encounter the +wrapped_app+ method again, which this time
we're going to explore more.
we're going to explore more (even though it was executed before, and
thus memoized by now).
<ruby>
@wrapped_app ||= build_app app
@ -494,7 +485,7 @@ app = eval "Rack::Builder.new {( " <plus> cfgfile <plus> "\n )}.to_app",
TOPLEVEL_BINDING, config
</ruby>
The +initialize+ method will take the block here and execute it within an instance of +Rack::Builder+. This is where the majority of the initialization process of Rails happens. The chain of events that this simple line sets off will be the focus of a large majority of this guide. The +require+ line for +config/environment.rb+ in +config.ru+ is the first to run:
The +initialize+ method of +Rack::Builder+ will take the block here and execute it within an instance of +Rack::Builder+. This is where the majority of the initialization process of Rails happens. The +require+ line for +config/environment.rb+ in +config.ru+ is the first to run:
<ruby>
require ::File.expand_path('../config/environment', __FILE__)
@ -541,641 +532,128 @@ require "rails"
end
</ruby>
First off the line is the +rails+ require itself.
This is where all the Rails frameworks are loaded and thus made
available to the application. We wont go into detail of what happens
inside each of those frameworks, but you're encouraged to try and
explore them on your own.
h4. +railties/lib/rails.rb+
For now, just keep in mind that common functionality like Rails engines,
I18n and Rails configuration is all bein defined here.
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.
h4. Back to +config/environment.rb+
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 1.9.3 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.
h4. +active_support/core_ext/kernel/reporting.rb+
This is the first of the many Active Support core extensions that come with Rails. This one in particular defines methods in the +Kernel+ module which is mixed in to the +Object+ class so the methods are available on +main+ and can therefore be called like this:
<ruby>
silence_warnings do
# some code
end
</ruby>
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/array/extract_options.rb+
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.
When +config/application.rb+ has finished loading Rails, and defined
your application namespace, you go back to +config/environment.rb+,
where your application is initialized. For example, if you application was called
+Blog+, here you would find +Blog::Application.initialize!+, which is
defined in +rails/application.rb+
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, +rails/engine+ is also loaded, which is responsible for
handling the behavior and definitions of Rails engines.
TIP: You can read more about engines in the "Getting Started with Engines":engines.html guide.
Among other things, Rails Engine is also responsible for loading the
Railtie class.
h4. +railties/lib/rails/railtie.rb+
The +rails/railtie.rb+ file is responsible for defining +Rails::Railtie+, the underlying class for all ties to Rails now. Gems that want to have their own initializers or rake tasks and hook into Rails should have a +GemName::Railtie+ class that inherits from +Rails::Railtie+.
The "API documentation":http://api.rubyonrails.org/classes/Rails/Railtie.html for +Rails::Railtie+, much like +Rails::Engine+, explains this class exceptionally well.
The first require in this file is +rails/initializable.rb+.
h4. +railties/lib/rails/initializable.rb+
Now we reach the end of this particular rabbit hole as +rails/initializable.rb+ doesn't require any more Rails files, only +tsort+ from the Ruby standard library.
This file defines the +Rails::Initializable+ module which contains the +Initializer+ class, the basis for all initializers in Rails. This module also contains a +ClassMethods+ class which will be included into the +Rails::Railtie+ class when these requires have finished.
Now that +rails/initializable.rb+ has finished being required from +rails/railtie.rb+, the next require is for +rails/configuration+.
h4. +railties/lib/rails/configuration.rb+
This file defines the +Rails::Configuration+ module, containing the +MiddlewareStackProxy+ class as well as the +Generators+ class. The +MiddlewareStackProxy+ class is used for managing the middleware stack for an application, which we'll see later on. The +Generators+ class provides the functionality used for configuring what generators an application uses through the "+config.generators+ option":configuring.html#configuring-generators.
The first file required in this file is +activesupport/deprecation+.
h4. +activesupport/lib/active_support/deprecation.rb+
This file, and the files it requires, define the basic deprecation warning features found in Rails. This file is responsible for setting defaults in the +ActiveSupport::Deprecation+ module for the +deprecation_horizon+, +silenced+ and +debug+ values. The files that are required before this happens are:
* +active_support/deprecation/behaviors+
* +active_support/deprecation/reporting+
* +active_support/deprecation/method_wrappers+
* +active_support/deprecation/proxy_wrappers+
h4. +activesupport/lib/active_support/deprecation/behaviors.rb+
This file defines the behavior of the +ActiveSupport::Deprecation+ module, setting up the +DEFAULT_BEHAVIORS+ hash constant which contains the three defaults to outputting deprecation warnings: +:stderr+, +:log+ and +:notify+. This file begins by requiring +activesupport/notifications+ and +activesupport/core_ext/array/wrap+.
h4. +activesupport/lib/active_support/notifications.rb+
This file defines the +ActiveSupport::Notifications+ module. Notifications provides an instrumentation API for Ruby, shipping with a queue implementation that consumes and publish events to log subscribers in a thread.
The "API documentation":http://api.rubyonrails.org/classes/ActiveSupport/Notifications.html for +ActiveSupport::Notifications+ explains the usage of this module, including the methods that it defines.
The file required in +active_support/notifications.rb+ is +active_support/core_ext/module/delegation+ which is documented in the "Active Support Core Extensions Guide":active_support_core_extensions.html#method-delegation.
h4. +activesupport/core_ext/array/wrap+
As this file comprises of a core extension, it is covered exclusively in "the Active Support Core Extensions guide":active_support_core_extensions.html#wrapping
h4. +activesupport/lib/active_support/deprecation/reporting.rb+
This file is responsible for defining the +warn+ and +silence+ methods for +ActiveSupport::Deprecation+ as well as additional private methods for this module.
h4. +activesupport/lib/active_support/deprecation/method_wrappers.rb+
This file defines a +deprecate_methods+ which is primarily used by the +module/deprecation+ core extension required by the first line of this file. Other core extensions required by this file are the +module/aliasing+ and +array/extract_options+ files.
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.
</plain>
h4. +active_support/ordered_options+
This file is the next file required from +rails/configuration.rb+ is the file that defines +ActiveSupport::OrderedOptions+ which is used for configuration options such as +config.active_support+ and the like.
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
h4. +active_support/core_ext/object+
This file is responsible for requiring many more Active Support core extensions:
The +initialize!+ method looks like this:
<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'
def initialize!(group=:default) #:nodoc:
raise "Application has been already initialized." if @initialized
run_initializers(group, self)
@initialized = true
self
end
</ruby>
The Rails API documentation covers them in great detail, so we're not going to explain each of them.
As you can see, you can only initialize an app once. This is also where the initializers are run.
The file that is required next from +rails/configuration+ is +rails/paths+.
TODO: review this
h4. +railties/lib/rails/paths.rb+
The initializers code itself is tricky. What Rails is doing here is it
traverses all the class ancestors looking for an +initializers+ method,
sorting them and running them. For example, the +Engine+ class will make
all the engines available by providing the +initializers+ method.
This file defines the +Rails::Paths+ module which allows paths to be configured for a Rails application or engine. Later on in this guide when we cover Rails configuration during the initialization process we'll see this used to set up some default paths for Rails and some of them will be configured to be eager loaded.
After this is done we go back to +Rack::Server+
h4. +railties/lib/rails/rack.rb+
h4. Rack: lib/rack/server.rb
The final file to be loaded by +railties/lib/rails/configuration.rb+ is +rails/rack+ which defines some simple autoloads:
Last time we left when the +app+ method was being defined:
<ruby>
module Rails
module Rack
autoload :Debugger, "rails/rack/debugger"
autoload :Logger, "rails/rack/logger"
autoload :LogTailer, "rails/rack/log_tailer"
def app
@app ||= begin
if !::File.exist? options[:config]
abort "configuration #{options[:config]} not found"
end
app, options = Rack::Builder.parse_file(self.options[:config], opt_parser)
self.options.merge! options
app
end
end
</ruby>
Once this file is finished loading, then the +Rails::Configuration+ class is initialized. This completes the loading of +railties/lib/rails/configuration.rb+ and now we jump back to the loading of +railties/lib/rails/railtie.rb+, where the next file loaded is +active_support/inflector+.
h4. +activesupport/lib/active_support/inflector.rb+
+active_support/inflector.rb+ requires a series of file which are responsible for setting up the basics for knowing how to pluralize and singularize words. These files are:
At this point +app+ is the Rails app itself (a middleware), and what
happens next is Rack will call all the provided middlewares:
<ruby>
require 'active_support/inflector/inflections'
require 'active_support/inflector/transliterate'
require 'active_support/inflector/methods'
require 'active_support/inflections'
require 'active_support/core_ext/string/inflections'
</ruby>
The +active_support/inflector/methods+ file has already been required by +active_support/autoload+ and so won't be loaded again here. The +activesupport/lib/active_support/inflector/inflections.rb+ is required by +active_support/inflector/methods+.
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+
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+
Once the inflector files have been loaded, the +Rails::Railtie+ class is defined. This class includes a module called +Initializable+, which is actually +Rails::Initializable+. This module includes the +initializer+ method which is used later on for setting up initializers, amongst other methods.
h4. +railties/lib/rails/initializable.rb+
When the module from this file (+Rails::Initializable+) is included, it extends the class it's included into with the +ClassMethods+ module inside of it. This module defines the +initializer+ method which is used to define initializers throughout all of the railties. This file completes the loading of +railties/lib/rails/railtie.rb+. Now we go back to +rails/engine.rb+.
h4. +railties/lib/rails/engine.rb+
The next file required in +rails/engine.rb+ is +active_support/core_ext/module/delegation+ which is documented in the "Active Support Core Extensions Guide":active_support_core_extensions.html#method-delegation.
The next two files after this are Ruby standard library files: +pathname+ and +rbconfig+. The file after these is +rails/engine/railties+.
h4. +railties/lib/rails/engine/railties.rb+
This file defines the +Rails::Engine::Railties+ class which provides the +engines+ and +railties+ methods which are used later on for defining rake tasks and other functionality for engines and railties.
h4. Back to +railties/lib/rails/engine.rb+
Once +rails/engine/railties.rb+ has finished loading the +Rails::Engine+ class gets its basic functionality defined, such as the +inherited+ method which will be called when this class is inherited from.
Once this file has finished loading we jump back to +railties/lib/rails/plugin.rb+
h4. Back to +railties/lib/rails/plugin.rb+
The next file required in this is a core extension from Active Support called +array/conversions+ which is covered in "this section":active_support_core_extensions.html#array-conversions of the Active Support Core Extensions Guide.
Once that file has finished loading, the +Rails::Plugin+ class is defined.
h4. Back to +railties/lib/rails/application.rb+
Jumping back to +rails/application.rb+ now. This file defines the +Rails::Application+ class where the application's class inherits from. This class (and its superclasses) define the basic behaviour on the application's constant such as the +config+ method used for configuring the application.
Once this file's done then we go back to the +railties/lib/rails.rb+ file, which next requires +rails/version+.
h4. +railties/lib/rails/version.rb+
Much like +active_support/version+, this file defines the +VERSION+ constant which has a +STRING+ constant on it which returns the current version of Rails.
Once this file has finished loading we go back to +railties/lib/rails.rb+ which then requires +active_support/railtie.rb+.
h4. +activesupport/lib/active_support/railtie.rb+
This file requires +active_support+ and +rails+ which have already been required so these two lines are effectively ignored. The third require in this file is to +active_support/i18n_railtie.rb+.
h4. +activesupport/lib/active_support/i18n_railtie.rb+
This file is the first file that sets up configuration with these lines inside the class:
<ruby>
class Railtie < Rails::Railtie
config.i18n = ActiveSupport::OrderedOptions.new
config.i18n.railties_load_path = []
config.i18n.load_path = []
config.i18n.fallbacks = ActiveSupport::OrderedOptions.new
</ruby>
By inheriting from +Rails::Railtie+ the +Rails::Railtie#inherited+ method is called:
<ruby>
def inherited(base)
unless base.abstract_railtie?
base.send(:include, Railtie::Configurable)
subclasses << base
def build_app(app)
middleware[options[:environment]].reverse_each do |middleware|
middleware = middleware.call(self) if middleware.respond_to?(:call)
next unless middleware
klass = middleware.shift
app = klass.new(app, *middleware)
end
app
end
</ruby>
This first checks if the Railtie that's inheriting it is a component of Rails itself:
Remember, +build_app+ was called (by wrapped_app) in the last line of +Server#start+.
Here's how it looked like when we left:
<ruby>
ABSTRACT_RAILTIES = %w(Rails::Railtie Rails::Plugin Rails::Engine Rails::Application)
server.run wrapped_app, options, &blk
</ruby>
...
At this point, the implementation of +server.run+ will depend on the
server you're using. For example, if you were using Mongrel, here's what
the +run+ method would look like:
def abstract_railtie?
ABSTRACT_RAILTIES.include?(name)
<ruby>
def self.run(app, options={})
server = ::Mongrel::HttpServer.new(
options[:Host] || '0.0.0.0',
options[:Port] || 8080,
options[:num_processors] || 950,
options[:throttle] || 0,
options[:timeout] || 60)
# Acts like Rack::URLMap, utilizing Mongrel's own path finding methods.
# Use is similar to #run, replacing the app argument with a hash of
# { path=>app, ... } or an instance of Rack::URLMap.
if options[:map]
if app.is_a? Hash
app.each do |path, appl|
path = '/'+path unless path[0] == ?/
server.register(path, Rack::Handler::Mongrel.new(appl))
end
</ruby>
Because +I18n::Railtie+ isn't in this list, +abstract_railtie?+ returns +false+. Therefore the +Railtie::Configurable+ module is included into this class and the +subclasses+ method is called and +I18n::Railtie+ is added to this new array.
<ruby>
def subclasses
@subclasses ||= []
elsif app.is_a? URLMap
app.instance_variable_get(:@mapping).each do |(host, path, appl)|
next if !host.nil? && !options[:Host].nil? && options[:Host] != host
path = '/'+path unless path[0] == ?/
server.register(path, Rack::Handler::Mongrel.new(appl))
end
</ruby>
The +config+ method used at the top of +I18n::Railtie+ is defined on +Rails::Railtie+ and is defined like this:
<ruby>
def config
@config ||= Railtie::Configuration.new
end
</ruby>
At this point, that +Railtie::Configuration+ constant is automatically loaded which causes the +rails/railties/configuration+ file to be loaded. The line for this is this particular line in +railties/lib/rails/railtie.rb+:
<ruby>
autoload :Configuration, "rails/railtie/configuration"
</ruby>
h4. +railties/lib/rails/railtie/configuration.rb+
This file begins with a require out to +rails/configuration+ which has already been required earlier in the process and so isn't required again.
This file defines the +Rails::Railtie::Configuration+ class which is responsible for providing a way to easily configure railties and it's the +initialize+ method here which is called by the +config+ method back in the +i18n_railtie.rb+ file. The methods on this object don't exist, and so are rescued by the +method_missing+ defined further down in +configuration.rb+:
<ruby>
def method_missing(name, *args, &blk)
if name.to_s =~ /=$/
@@options[$`.to_sym] = args.first
elsif @@options.key?(name)
@@options[name]
else
super
raise ArgumentError, "first argument should be a Hash or URLMap"
end
end
</ruby>
So therefore when an option is referred to it simply stores the value as the key if it's used in a setter context, or retrieves it if used in a getter context. Nothing fancy going on there.
h4. Back to +activesupport/lib/active_support/i18n_railtie.rb+
After the configuration method the +reloader+ method is defined, and then the first of of Railties' initializers is defined: +i18n.callbacks+.
<ruby>
initializer "i18n.callbacks" do
ActionDispatch::Reloader.to_prepare do
I18n::Railtie.reloader.execute_if_updated
end
end
</ruby>
The +initializer+ method (from the +Rails::Initializable+ module) here doesn't run the block, but rather stores it to be run later on:
<ruby>
def initializer(name, opts = {}, &blk)
raise ArgumentError, "A block must be passed when defining an initializer" unless blk
opts[:after] ||= initializers.last.name unless initializers.empty? || initializers.find { |i| i.name == opts[:before] }
initializers << Initializer.new(name, nil, opts, &blk)
end
</ruby>
An initializer can be configured to run before or after another initializer, which we'll see a couple of times throughout this initialization process. Anything that inherits from +Rails::Railtie+ may also make use of the +initializer+ method, something which is covered in the "Configuration guide":configuring.html#rails-railtie-initializer.
The +Initializer+ class here is defined within the +Rails::Initializable+ module and its +initialize+ method is defined to just set up a couple of variables:
<ruby>
def initialize(name, context, options, &block)
@name, @context, @options, @block = name, context, options, block
end
</ruby>
Once this +initialize+ method is finished, the object is added to the object the +initializers+ method returns:
<ruby>
def initializers
@initializers ||= self.class.initializers_for(self)
end
</ruby>
If +@initializers+ isn't set (which it won't be at this point), the +intializers_for+ method will be called for this class.
<ruby>
def initializers_for(binding)
Collection.new(initializers_chain.map { |i| i.bind(binding) })
end
</ruby>
The +Collection+ class in +railties/lib/rails/initializable.rb+ inherits from +Array+ and includes the +TSort+ module which is used to sort out the order of the initializers based on the order they are placed in.
The +initializers_chain+ method referenced in the +initializers_for+ method is defined like this:
<ruby>
def initializers_chain
initializers = Collection.new
ancestors.reverse_each do |klass|
next unless klass.respond_to?(:initializers)
initializers = initializers + klass.initializers
end
initializers
end
</ruby>
This method collects the initializers from the ancestors of this class and adds them to a new +Collection+ object using the <tt>+</tt> method which is defined like this for the <tt>Collection</tt> class:
<ruby>
def +(other)
Collection.new(to_a + other.to_a)
end
</ruby>
So this <tt>+</tt> method is overridden to return a new collection comprising of the existing collection as an array and then using the <tt>Array#+</tt> method combines these two collections, returning a "super" +Collection+ object. In this case, the only initializer that's going to be in this new +Collection+ object is the +i18n.callbacks+ initializer.
The next method to be called after this +initializer+ method is the +after_initialize+ method on the +config+ object, which is defined like this:
<ruby>
def after_initialize(&block)
ActiveSupport.on_load(:after_initialize, :yield => true, &block)
end
</ruby>
The +on_load+ method here is provided by the +active_support/lazy_load_hooks+ file which was required earlier and is defined like this:
<ruby>
def self.on_load(name, options = {}, &block)
if base = @loaded[name]
execute_hook(base, options, block)
else
@load_hooks[name] << [block, options]
server.register('/', Rack::Handler::Mongrel.new(app))
end
yield server if block_given?
server.run.join
end
</ruby>
The +@loaded+ variable here is a hash containing elements representing the different components of Rails that have been loaded at this stage. Currently, this hash is empty. So the +else+ is executed here, using the +@load_hooks+ variable defined in +active_support/lazy_load_hooks+:
We wont dig into the server configuration itself, but this is
the last piece of our journey in the Rails initialization process.
<ruby>
@load_hooks = Hash.new {|h,k| h[k] = [] }
</ruby>
This defines a new hash which has keys that default to empty arrays. This saves Rails from having to do something like this instead:
<ruby>
@load_hooks[name] = []
@load_hooks[name] << [block, options]
</ruby>
The value added to this array here consists of the block and options passed to +after_initialize+.
We'll see these +@load_hooks+ used later on in the initialization process.
This rest of +i18n_railtie.rb+ defines the protected class methods +include_fallback_modules+, +init_fallbacks+ and +validate_fallbacks+.
h4. Back to +activesupport/lib/active_support/railtie.rb+
This file defines the +ActiveSupport::Railtie+ constant which like the +I18n::Railtie+ constant just defined, inherits from +Rails::Railtie+ meaning the +inherited+ method would be called again here, including +Rails::Configurable+ into this class. This class makes use of +Rails::Railtie+'s +config+ method again, setting up the configuration options for Active Support.
Then this Railtie sets up three more initializers:
* +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. +actionpack/lib/action_dispatch/railtie.rb+
This file defines the +ActionDispatch::Railtie+ class, but not before requiring +action_dispatch+.
h4. +actionpack/lib/action_dispatch.rb+
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+ (+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 = 4
MINOR = 0
TINY = 0
PRE = "beta"
STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
end
end
</ruby>
Once +action_pack+ is finished, then +active_model+ is required.
h4. +activemodel/lib/active_model.rb+
This file makes a require to +active_model/version+ which defines the version for Active Model:
<ruby>
module ActiveModel
module VERSION #:nodoc:
MAJOR = 4
MINOR = 0
TINY = 0
PRE = "beta"
STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
end
end
</ruby>
Once the +version.rb+ file is loaded, the +ActiveModel+ module has its autoloaded constants defined as well as a sub-module called +ActiveModel::Serializers+ which has autoloads of its own. When the +ActiveModel+ module is closed the +active_support/i18n+ file is required.
h4. +activesupport/lib/active_support/i18n.rb+
This is where the +i18n+ gem is required and first configured:
<ruby>
begin
require 'i18n'
require 'active_support/lazy_load_hooks'
rescue LoadError => e
$stderr.puts "You don't have i18n installed in your application. Please add it to your Gemfile and run bundle install"
raise e
end
I18n.load_path << "#{File.dirname(__FILE__)}/locale/en.yml"
</ruby>
In effect, the +I18n+ module first defined by +i18n_railtie+ is extended by the +i18n+ gem, rather than the other way around. This has no ill effect. They both work on the same way.
This is another spot where +active_support/lazy_load_hooks+ is required, but it has already been required so it's not loaded again.
If +i18n+ cannot be loaded, the user is presented with an error which says that it cannot be loaded and recommends that it's added to the +Gemfile+. However, in a normal Rails application this gem would be loaded.
Once it has finished loading, the +I18n.load_path+ method is used to add the +activesupport/lib/active_support/locale/en.yml+ file to I18n's load path. When the translations are loaded in the initialization process, this is one of the files where they will be sourced from.
The loading of this file finishes the loading of +active_model+ and so we go back to +action_dispatch+.
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:
<ruby>
autoload_under 'testing' do
autoload :Assertions
...
</ruby>
The +Assertions+ module is in the +action_dispatch/testing+ folder rather than simply +action_dispatch+.
Finally, this file defines a top-level autoload, the +Mime+ constant.
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+.
With +action_dispatch/railtie+ now complete, we go back to +railties/lib/rails.rb+.
h4. Back to +railties/lib/rails.rb+
With the Active Support and Action Dispatch railties now both loaded, the rest of this file deals with setting up UTF-8 to be the default encoding for Rails and then finally setting up the +Rails+ module. This module defines useful methods such as +Rails.logger+, +Rails.application+, +Rails.env+, and +Rails.root+.
h4. Back to +railties/lib/rails/all.rb+
Now that +rails.rb+ is required, the remaining railties are loaded next, beginning with +active_record/railtie+.
h4. +activerecord/lib/active_record/railtie.rb+
Before this file gets into the swing of defining the +ActiveRecord::Railtie+ class, there are a couple of files that are required first. The first one of these is +active_record+.
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 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_model'
require 'arel'
</ruby>
The file required next is +active_record/version+ which defines the +ActiveRecord::VERSION+ constant:
<ruby>
module ActiveRecord
module VERSION #:nodoc:
MAJOR = 4
MINOR = 0
TINY = 0
PRE = "beta"
STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
end
end
</ruby>
Once these requires are finished, the base for the +ActiveRecord+ module is defined along with its autoloads.
Near the end of the file, we see this line:
<ruby>
ActiveSupport.on_load(:active_record) do
Arel::Table.engine = self
end
</ruby>
This will set the engine for +Arel::Table+ to be +ActiveRecord::Base+.
The file then finishes with this line:
<ruby>
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.
h4. Back to +activerecord/lib/active_record/railtie.rb+
The next two <tt>require</tt>s in this file aren't run because their files are already required, with +rails+ being required by +rails/all+ and +active_model/railtie+ being required from +action_dispatch+.
<ruby>
require "rails"
require "active_model/railtie"
</ruby>
The next +require+ in this file is to +action_controller/railtie+.
h4. +actionpack/lib/action_controller/railtie.rb+
This file begins with a couple more requires to files that have already been loaded:
<ruby>
require "rails"
require "action_controller"
require "action_dispatch/railtie"
</ruby>
However the require after these is to a file that hasn't yet been loaded, +action_view/railtie+, which begins by requiring +action_view+.
h4. +actionpack/lib/action_view.rb+
+action_view.rb+
This high level overview will help you understand when you code is
executed and how, and overall become a better Rails developer. If you
still want to know more, the Rails source code itself is probably the
best place to go next.

2
guides/source/layouts_and_rendering.textile
View file

@ -23,8 +23,6 @@ From the controller's point of view, there are three ways to create an HTTP resp
* Call +redirect_to+ to send an HTTP redirect status code to the browser
* Call +head+ to create a response consisting solely of HTTP headers to send back to the browser
I'll cover each of these methods in turn. But first, a few words about the very easiest thing that the controller can do to create a response: nothing at all.
h4. Rendering by Default: Convention Over Configuration in Action
You've heard that Rails promotes "convention over configuration". Default rendering is an excellent example of this. By default, controllers in Rails automatically render views with names that correspond to valid routes. For example, if you have this code in your +BooksController+ class: