ActionController源码（待续）

/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb

module ActionController #:nodoc:
class Base
    DEFAULT_RENDER_STATUS_CODE = "200 OK"

    include StatusCodes

    cattr_reader :protected_instance_variables
    # Controller specific instance variables which will not be accessible inside views.
    @@protected_instance_variables = %w(@assigns @performed_redirect @performed_render @variables_added @request_origin @url @parent_controller
                                        @action_name @before_filter_chain_aborted @action_cache_path @_session @_headers @_params
                                        @_flash @_response)

    # Prepends all the URL-generating helpers from AssetHelper. This makes it possible to easily move javascripts, stylesheets,
    # and images to a dedicated asset server away from the main web server. Example:
    #   ActionController::Base.asset_host = "http://assets.example.com"
    @@asset_host = ""
    cattr_accessor :asset_host

    # All requests are considered local by default, so everyone will be exposed to detailed debugging screens on errors.
    # When the application is ready to go public, this should be set to false, and the protected method <tt>local_request?</tt>
    # should instead be implemented in the controller to determine when debugging screens should be shown.
    @@consider_all_requests_local = true
    cattr_accessor :consider_all_requests_local

    # Indicates whether to allow concurrent action processing. Your
    # controller actions and any other code they call must also behave well
    # when called from concurrent threads. Turned off by default.
    @@allow_concurrency = false
    cattr_accessor :allow_concurrency

    # Modern REST web services often need to submit complex data to the web application.
    # The <tt>@@param_parsers</tt> hash lets you register handlers which will process the HTTP body and add parameters to the
    # <tt>params</tt> hash. These handlers are invoked for POST and PUT requests.
    #
    # By default <tt>application/xml</tt> is enabled. A XmlSimple class with the same param name as the root will be instantiated
    # in the <tt>params</tt>. This allows XML requests to mask themselves as regular form submissions, so you can have one
    # action serve both regular forms and web service requests.
    #
    # Example of doing your own parser for a custom content type:
    #
    #   ActionController::Base.param_parsers[Mime::Type.lookup('application/atom+xml')] = Proc.new do |data|
    #      node = REXML::Document.new(post)
    #     { node.root.name => node.root }
    #   end
    #
    # Note: Up until release 1.1 of Rails, Action Controller would default to using XmlSimple configured to discard the
    # root node for such requests. The new default is to keep the root, such that "<r><name>David</name></r>" results
    # in <tt>params[:r][:name]</tt> for "David" instead of <tt>params[:name]</tt>. To get the old behavior, you can
    # re-register XmlSimple as application/xml handler ike this:
    #
    #   ActionController::Base.param_parsers[Mime::XML] =
    #     Proc.new { |data| XmlSimple.xml_in(data, 'ForceArray' => false) }
    #
    # A YAML parser is also available and can be turned on with:
    #
    #   ActionController::Base.param_parsers[Mime::YAML] = :yaml
    @@param_parsers = {}
    cattr_accessor :param_parsers

    # Controls the default charset for all renders.
    @@default_charset = "utf-8"
    cattr_accessor :default_charset

    # The logger is used for generating information on the action run-time (including benchmarking) if available.
    # Can be set to nil for no logging. Compatible with both Ruby's own Logger and Log4r loggers.
    cattr_accessor :logger

    # Controls the resource action separator
    @@resource_action_separator = "/"
    cattr_accessor :resource_action_separator

    # Allow to override path names for default resources' actions
    @@resources_path_names = { :new => 'new', :edit => 'edit' }
    cattr_accessor :resources_path_names

    # Sets the token parameter name for RequestForgery. Calling +protect_from_forgery+
    # sets it to <tt>:authenticity_token</tt> by default.
    cattr_accessor :request_forgery_protection_token

    # Controls the IP Spoofing check when determining the remote IP.
    @@ip_spoofing_check = true
    cattr_accessor :ip_spoofing_check

    # Indicates whether or not optimise the generated named
    # route helper methods
    cattr_accessor :optimise_named_routes
    self.optimise_named_routes = true

    # Indicates whether the response format should be determined by examining the Accept HTTP header,
    # or by using the simpler params + ajax rules.
    #
    # If this is set to +true+ (the default) then +respond_to+ and +Request#format+ will take the Accept
    # header into account.  If it is set to false then the request format will be determined solely
    # by examining params[:format].  If params format is missing, the format will be either HTML or
    # Javascript depending on whether the request is an AJAX request.
    cattr_accessor :use_accept_header
    self.use_accept_header = true

    # Controls whether request forgergy protection is turned on or not. Turned off by default only in test mode.
    class_inheritable_accessor :allow_forgery_protection
    self.allow_forgery_protection = true

    # If you are deploying to a subdirectory, you will need to set
    # <tt>config.action_controller.relative_url_root</tt>
    # This defaults to ENV['RAILS_RELATIVE_URL_ROOT']
    cattr_accessor :relative_url_root
    self.relative_url_root = ENV['RAILS_RELATIVE_URL_ROOT']

    # Holds the request object that's primarily used to get environment variables through access like
    # <tt>request.env["REQUEST_URI"]</tt>.
    attr_internal :request

    # Holds a hash of all the GET, POST, and Url parameters passed to the action. Accessed like <tt>params["post_id"]</tt>
    # to get the post_id. No type casts are made, so all values are returned as strings.
    attr_internal :params

    # Holds the response object that's primarily used to set additional HTTP headers through access like
    # <tt>response.headers["Cache-Control"] = "no-cache"</tt>. Can also be used to access the final body HTML after a template
    # has been rendered through response.body -- useful for <tt>after_filter</tt>s that wants to manipulate the output,
    # such as a OutputCompressionFilter.
    attr_internal :response

    # Holds a hash of objects in the session. Accessed like <tt>session[:person]</tt> to get the object tied to the "person"
    # key. The session will hold any type of object as values, but the key should be a string or symbol.
    attr_internal :session

    # Holds a hash of header names and values. Accessed like <tt>headers["Cache-Control"]</tt> to get the value of the Cache-Control
    # directive. Values should always be specified as strings.
    attr_internal :headers

    # Returns the name of the action this controller is processing.
    attr_accessor :action_name
  end
end

/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/core_ext/module/attr_internal.rb

class Module
  # Declares an attribute reader backed by an internally-named instance variable.
  def attr_internal_reader(*attrs)
    attrs.each do |attr|
      module_eval "def #{attr}() #{attr_internal_ivar_name(attr)} end"
    end
  end

  # Declares an attribute writer backed by an internally-named instance variable.
  def attr_internal_writer(*attrs)
    attrs.each do |attr|
      module_eval "def #{attr}=(v) #{attr_internal_ivar_name(attr)} = v end"
    end
  end

  # Declares an attribute reader and writer backed by an internally-named instance
  # variable.
  def attr_internal_accessor(*attrs)
    attr_internal_reader(*attrs)
    attr_internal_writer(*attrs)
  end

  alias_method :attr_internal, :attr_internal_accessor

  private
    mattr_accessor :attr_internal_naming_format
    self.attr_internal_naming_format = '@_%s'

    def attr_internal_ivar_name(attr)
      attr_internal_naming_format % attr
    end
end

/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/core_ext/module/attribute_accessors.rb

# Extends the module object with module and instance accessors for class attributes, 
# just like the native attr* accessors for instance attributes.
#
#  module AppConfiguration
#    mattr_accessor :google_api_key
#    self.google_api_key = "123456789"
#
#    mattr_accessor :paypal_url
#    self.paypal_url = "www.sandbox.paypal.com"
#  end
#
#  AppConfiguration.google_api_key = "overriding the api key!"
class Module
  def mattr_reader(*syms)
    syms.each do |sym|
      next if sym.is_a?(Hash)
      class_eval(<<-EOS, __FILE__, __LINE__)
        unless defined? @@#{sym}  # unless defined? @@pagination_options
          @@#{sym} = nil          #   @@pagination_options = nil
        end                       # end
                                  #
        def self.#{sym}           # def self.pagination_options
          @@#{sym}                #   @@pagination_options
        end                       # end
                                  #
        def #{sym}                # def pagination_options
          @@#{sym}                #   @@pagination_options
        end                       # end
      EOS
    end
  end
  
  def mattr_writer(*syms)
    options = syms.extract_options!
    syms.each do |sym|
      class_eval(<<-EOS, __FILE__, __LINE__)
        unless defined? @@#{sym}                       # unless defined? @@pagination_options
          @@#{sym} = nil                               #   @@pagination_options = nil
        end                                            # end
                                                       #
        def self.#{sym}=(obj)                          # def self.pagination_options=(obj)
          @@#{sym} = obj                               #   @@pagination_options = obj
        end                                            # end
                                                       #
        #{"                                            #
        def #{sym}=(obj)                               # def pagination_options=(obj)
          @@#{sym} = obj                               #   @@pagination_options = obj
        end                                            # end
        " unless options[:instance_writer] == false }  # # instance writer above is generated unless options[:instance_writer] == false
      EOS
    end
  end
  
  def mattr_accessor(*syms)
    mattr_reader(*syms)
    mattr_writer(*syms)
  end
end