Rails源码研究之ActionController:六，request

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Ruby

Rails CGI Ruby XML Cache

看看Rails的request/response源码吧，非常有趣，有些方法非常实用
1，request.rb:

module ActionController
  class AbstractRequest

    def method
      @request_method ||= (!parameters[:_method].blank? && @env['REQUEST_METHOD'] == 'POST') ?
        parameters[:_method].to_s.downcase.to_sym :
        @env['REQUEST_METHOD'].downcase.to_sym
      @request_method == :head ? :get : @request_method
    end

    def get?
      method == :get
    end

    def post?
      method == :post
    end

    def put?
      method == :put
    end

    def delete?
      method == :delete
    end

    def head?
      @env['REQUEST_METHOD'].downcase.to_sym = :head
    end

    def content_type
      @content_type ||=
        begin
          content_type = @env['CONTENT_TYPE'].to_s.downcase
          if x_post_format = @env['HTTP_X_POST_DATA_FORMAT']
            case x_post_format.to_s.downcase
            when 'yaml'
              content_type = 'application/x-yaml'
            when 'xml'
              content_type = 'application/xml'
            end
          end
          Mime::Type.lookup(content_type)
        end
    end

    def accepts
      @accepts ||=
        if @env['HTTP_ACCEPT'].to_s.strip.empty?
          [ content_type, Mime::ALL ]
        else
          Mime::Type.parse(@env['HTTP_ACCEPT'])
        end
    end

    def xml_http_request?
      not /XMLHttpRequest/i.match(@env['HTTP_X_REQUESTED_WITH']).nil?
    end
    alias xhr? :xml_http_request?

    def remote_ip
      return @env['HTTP_CLIENT_IP'] if @env.include? 'HTTP_CLIENT_IP'
      if @env.include? 'HTTP_X_FORWARDED_FOR' then
        remote_ips = @env['HTTP_X_FORWARDED_FOR'].split(',').reject do |ip|
            ip =~ /^unknown$|^(10|172\.(1[6-9]|2[0-9]|30|31)|192\.168)\./i
        end
        return remote_ips.first.strip unless remote_ips.empty?
      end
      @env['REMOTE_ADDR']
    end

    def domain(tld_length = 1)
      return nil if !/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/.match(host).nil? or host.nil?
      host.split('.').last(1 + tld_length).join('.')
    end

    def subdomains(tld_length = 1)
      return [] unless host
      parts = host.split('.')
      parts[0..-(tld_length+2)]
    end

    def request_uri
      if uri = @env['REQUEST_URI']
        (%r{^\w+\://[^/]+(/.*|$)$} =~ uri) ? $1 : uri
      else
        script_filename = @env['SCRIPT_NAME'].to_s.match(%r{[^/]+$})
        uri = @env['PATH_INFO']
        uri = uri.sub(/#{script_filename}\//, '') unless script_filename.nil?
        unless (env_qs = @env['QUERY_STRING']).nil? || env_qs.empty?
          uri << '?' << env_qs
        end
        @env['REQUEST_URI'] = uri
      end
    end

    def protocol
      ssl? ? 'https://' : 'http://'
    end

    def ssl?
      @env['HTTPS'] == 'on' || @env['HTTP_X_FORWARDED_PROTO'] == 'https'
    end

    def port
      @port_as_int ||= @env['SERVER_PORT'].to_i
    end

    def cookies
    end

    def session
    end

  end
end

2，response.rb:

module ActionController
  class AbstractResponse
    DEFAULT_HEADERS = { "Cache-Control" => "no-cache" }
    attr_accessor :body, :headers, :session, :cookies, :assigns, :template, :redirected_to, :redirected_to_method_params, :layout

    def initialize
      @body, @headers, @session, @assigns = "", DEFAULT_HEADERS.merge("cookie" => []), [], []
    end

    def content_type=(mime_type)
      @headers["Content-Type"] = charset ? "#{mime_type}; charset=#{charset}" : mime_type
    end
    
    def content_type
      content_type = String(@headers["Content-Type"]).split(";")[0]
      content_type.blank? ? nil : content_type
    end
    
    def charset=(encoding)
      @headers["Content-Type"] = "#{content_type || "text/html"}; charset=#{encoding}"
    end
    
    def charset
      charset = String(@headers["Content-Type"]).split(";")[1]
      charset.blank? ? nil : charset.strip.split("=")[1]
    end

    def redirect(to_url, permanently = false)
      @headers["Status"]   = "302 Found" unless @headers["Status"] == "301 Moved Permanently"
      @headers["Location"] = to_url
      @body = "<html><body>You are being <a href=\"#{to_url}\">redirected</a>.</body></html>"
    end
  end
end

3，cgi_process.rb:

module ActionController
  class Base
    def self.process_cgi(cgi = CGI.new, session_options = {})
      new.process_cgi(cgi, session_options)
    end

    def process_cgi(cgi, session_options = {})
      process(CgiRequest.new(cgi, session_options), CgiResponse.new(cgi)).out
    end
  end

  class CgiRequest < AbstractRequest
    attr_accessor :cgi, :session_options
    DEFAULT_SESSION_OPTIONS = {
      :database_manager => CGI::Session::PStore,
      :prefix           => "ruby_sess.",
      :session_path     => "/"
    } unless const_defined?(:DEFAULT_SESSION_OPTIONS)

    def initialize(cgi, session_options = {})
      @cgi = cgi
      @session_options = session_options
      @env = @cgi.send(:env_table)
      super()
    end

    def cookies
      @cgi.cookies.freeze
    end

    def session
      unless defined?(@session)
        if @session_options == false
          @session = Hash.new
        else
          stale_session_check! do
            case value = session_options_with_string_keys['new_session']
              when true
                @session = new_session
              when false
                begin
                  @session = CGI::Session.new(@cgi, session_options_with_string_keys)
                rescue ArgumentError
                  @session = Hash.new
                end
              when nil
                @session = CGI::Session.new(@cgi, session_options_with_string_keys)
              else
                raise ArgumentError, "Invalid new_session option: #{value}"
            end
            @session['__valid_session']
          end
        end
      end
      @session
    end
  end

  class CgiResponse < AbstractResponse
    def initialize(cgi)
      @cgi = cgi
      super()
    end

    def out(output = $stdout)
      convert_content_type!
      set_content_length!
      output.binmode      if output.respond_to?(:binmode)
      output.sync = false if output.respond_to?(:sync=)
      begin
        output.write(@cgi.header(@headers))
        if @cgi.send(:env_table)['REQUEST_METHOD'] == 'HEAD'
          return
        elsif @body.respond_to?(:call)
          output.flush if output.respond_to?(:flush)
          @body.call(self, output)
        else
          output.write(@body)
        end
        output.flush if output.respond_to?(:flush)
      rescue Errno::EPIPE, Errno::ECONNRESET
      end
    end
  end
end

Controller的入口方法process_cgi调用了process方法，参数为CgiRequest对象和CgiResponse对象，process处理action调用和模板render，然后返回response.out方法的返回值
CgiResponse的out方法则调用output.write(@body)，即write response.body并返回给浏览器端，这就是一个Rails URL访问的完整流程

request里有很多有用的方法，request.method、request.xhr?、request.remote_ip、request.subdomains、request.session、request.cookies等都是我们常用的

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ActiveRecord的lazy loading与eager loadin ... | Rails源码研究之ActionController:五，co ...

2007-06-26 13:04
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2 楼 blackanger 2007-06-27

都在学习，忘了顶了。。。

1 楼 sina2009 2007-06-27

学习
很奇怪这么好的文章咋就一直没人顶呢

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