response.rb

   1 require 'digest/md5'
   2
   3 module ActionController # :nodoc:
   4   # Represents an HTTP response generated by a controller action. One can use an
   5   # ActionController::AbstractResponse object to retrieve the current state of the
   6   # response, or customize the response. An AbstractResponse object can either
   7   # represent a "real" HTTP response (i.e. one that is meant to be sent back to the
   8   # web browser) or a test response (i.e. one that is generated from integration
   9   # tests). See CgiResponse and TestResponse, respectively.
  10   #
  11   # AbstractResponse is mostly a Ruby on Rails framework implement detail, and should
  12   # never be used directly in controllers. Controllers should use the methods defined
  13   # in ActionController::Base instead. For example, if you want to set the HTTP
  14   # response's content MIME type, then use ActionControllerBase#headers instead of
  15   # AbstractResponse#headers.
  16   #
  17   # Nevertheless, integration tests may want to inspect controller responses in more
  18   # detail, and that's when AbstractResponse can be useful for application developers.
  19   # Integration test methods such as ActionController::Integration::Session#get and
  20   # ActionController::Integration::Session#post return objects of type TestResponse
  21   # (which are of course also of type AbstractResponse).
  22   #
  23   # For example, the following demo integration "test" prints the body of the
  24   # controller response to the console:
  25   #
  26   #  class DemoControllerTest < ActionController::IntegrationTest
  27   #    def test_print_root_path_to_console
  28   #      get('/')
  29   #      puts @response.body
  30   #    end
  31   #  end
  32   class AbstractResponse
  33     DEFAULT_HEADERS = { "Cache-Control" => "no-cache" }
  34     attr_accessor :request
  35
  36     # The body content (e.g. HTML) of the response, as a String.
  37     attr_accessor :body
  38     # The headers of the response, as a Hash. It maps header names to header values.
  39     attr_accessor :headers
  40     attr_accessor :session, :cookies, :assigns, :template, :layout
  41     attr_accessor :redirected_to, :redirected_to_method_params
  42
  43     delegate :default_charset, :to => 'ActionController::Base'
  44
  45     def initialize
  46       @body, @headers, @session, @assigns = "", DEFAULT_HEADERS.merge("cookie" => []), [], []
  47     end
  48
  49     def status; headers['Status'] end
  50     def status=(status) headers['Status'] = status end
  51
  52     def location; headers['Location'] end
  53     def location=(url) headers['Location'] = url end
  54
  55
  56     # Sets the HTTP response's content MIME type. For example, in the controller
  57     # you could write this:
  58     #
  59     #  response.content_type = "text/plain"
  60     #
  61     # If a character set has been defined for this response (see charset=) then
  62     # the character set information will also be included in the content type
  63     # information.
  64     def content_type=(mime_type)
  65       self.headers["Content-Type"] =
  66         if mime_type =~ /charset/ || (c = charset).nil?
  67           mime_type.to_s
  68         else
  69           "#{mime_type}; charset=#{c}"
  70         end
  71     end
  72
  73     # Returns the response's content MIME type, or nil if content type has been set.
  74     def content_type
  75       content_type = String(headers["Content-Type"] || headers["type"]).split(";")[0]
  76       content_type.blank? ? nil : content_type
  77     end
  78
  79     # Set the charset of the Content-Type header. Set to nil to remove it.
  80     # If no content type is set, it defaults to HTML.
  81     def charset=(charset)
  82       headers["Content-Type"] =
  83         if charset
  84           "#{content_type || Mime::HTML}; charset=#{charset}"
  85         else
  86           content_type || Mime::HTML.to_s
  87         end
  88     end
  89
  90     def charset
  91       charset = String(headers["Content-Type"] || headers["type"]).split(";")[1]
  92       charset.blank? ? nil : charset.strip.split("=")[1]
  93     end
  94
  95     def last_modified
  96       if last = headers['Last-Modified']
  97         Time.httpdate(last)
  98       end
  99     end
 100
 101     def last_modified?
 102       headers.include?('Last-Modified')
 103     end
 104
 105     def last_modified=(utc_time)
 106       headers['Last-Modified'] = utc_time.httpdate
 107     end
 108
 109     def etag
 110       headers['ETag']
 111     end
 112
 113     def etag?
 114       headers.include?('ETag')
 115     end
 116
 117     def etag=(etag)
 118       headers['ETag'] = %("#{Digest::MD5.hexdigest(ActiveSupport::Cache.expand_cache_key(etag))}")
 119     end
 120
 121     def redirect(url, status)
 122       self.status = status
 123       self.location = url.gsub(/[\r\n]/, '')
 124       self.body = "<html><body>You are being <a href=\"#{CGI.escapeHTML(url)}\">redirected</a>.</body></html>"
 125     end
 126
 127     def sending_file?
 128       headers["Content-Transfer-Encoding"] == "binary"
 129     end
 130
 131     def assign_default_content_type_and_charset!
 132       self.content_type ||= Mime::HTML
 133       self.charset ||= default_charset unless sending_file?
 134     end
 135
 136     def prepare!
 137       assign_default_content_type_and_charset!
 138       handle_conditional_get!
 139       set_content_length!
 140       convert_content_type!
 141     end
 142
 143     private
 144       def handle_conditional_get!
 145         if etag? || last_modified?
 146           set_conditional_cache_control!
 147         elsif nonempty_ok_response?
 148           self.etag = body
 149
 150           if request && request.etag_matches?(etag)
 151             self.status = '304 Not Modified'
 152             self.body = ''
 153           end
 154
 155           set_conditional_cache_control!
 156         end
 157       end
 158
 159       def nonempty_ok_response?
 160         ok = !status || status[0..2] == '200'
 161         ok && body.is_a?(String) && !body.empty?
 162       end
 163
 164       def set_conditional_cache_control!
 165         if headers['Cache-Control'] == DEFAULT_HEADERS['Cache-Control']
 166           headers['Cache-Control'] = 'private, max-age=0, must-revalidate'
 167         end
 168       end
 169
 170       def convert_content_type!
 171         if content_type = headers.delete("Content-Type")
 172           self.headers["type"] = content_type
 173         end
 174         if content_type = headers.delete("Content-type")
 175           self.headers["type"] = content_type
 176         end
 177         if content_type = headers.delete("content-type")
 178           self.headers["type"] = content_type
 179         end
 180       end
 181
 182       # Don't set the Content-Length for block-based bodies as that would mean reading it all into memory. Not nice
 183       # for, say, a 2GB streaming file.
 184       def set_content_length!
 185         unless body.respond_to?(:call) || (status && status[0..2] == '304')
 186           self.headers["Content-Length"] ||= body.size
 187         end
 188       end
 189   end
 190 end