4 files changed, 20 insertions, 14 deletions
diff --git a/actionpack/lib/action_dispatch/http/headers.rb b/actionpack/lib/action_dispatch/http/headers.rb
index 040b51e040..a3bb25f75a 100644
--- a/actionpack/lib/action_dispatch/http/headers.rb
+++ b/actionpack/lib/action_dispatch/http/headers.rb
@@ -14,17 +14,18 @@ module ActionDispatch
       end
 
       def [](header_name)
-        if include?(header_name)
-          super
-        else
-          super(env_name(header_name))
-        end
+        super env_name(header_name)
+      end
+
+      def fetch(header_name, default=nil, &block)
+        super env_name(header_name), default, &block
       end
 
       private
-        # Converts a HTTP header name to an environment variable name.
+        # Converts a HTTP header name to an environment variable name if it is
+        # not contained within the headers hash.
         def env_name(header_name)
-          @@env_cache[header_name]
+          include?(header_name) ? header_name : @@env_cache[header_name]
         end
     end
   end
diff --git a/actionpack/lib/action_dispatch/http/mime_type.rb b/actionpack/lib/action_dispatch/http/mime_type.rb
index 26f4c16218..0eaae80461 100644
--- a/actionpack/lib/action_dispatch/http/mime_type.rb
+++ b/actionpack/lib/action_dispatch/http/mime_type.rb
@@ -179,11 +179,11 @@ module Mime
         end
       end
 
-      # input: 'text'
-      # returned value:  [Mime::JSON, Mime::XML, Mime::ICS, Mime::HTML, Mime::CSS, Mime::CSV, Mime::JS, Mime::YAML, Mime::TEXT]
+      # For an input of <tt>'text'</tt>, returns <tt>[Mime::JSON, Mime::XML, Mime::ICS,
+      # Mime::HTML, Mime::CSS, Mime::CSV, Mime::JS, Mime::YAML, Mime::TEXT]</tt>.
       #
-      # input: 'application'
-      # returned value: [Mime::HTML, Mime::JS, Mime::XML, Mime::YAML, Mime::ATOM, Mime::JSON, Mime::RSS, Mime::URL_ENCODED_FORM]
+      # For an input of <tt>'application'</tt>, returns <tt>[Mime::HTML, Mime::JS,
+      # Mime::XML, Mime::YAML, Mime::ATOM, Mime::JSON, Mime::RSS, Mime::URL_ENCODED_FORM]</tt>.
       def parse_data_with_trailing_star(input)
         Mime::SET.select { |m| m =~ input }
       end
@@ -192,7 +192,7 @@ module Mime
       #
       # Usage:
       #
-      # Mime::Type.unregister(:mobile)
+      #   Mime::Type.unregister(:mobile)
       def unregister(symbol)
         symbol = symbol.to_s.upcase
         mime = Mime.const_get(symbol)
diff --git a/actionpack/lib/action_dispatch/http/parameters.rb b/actionpack/lib/action_dispatch/http/parameters.rb
index d9b63faf5e..bcfd0b0d00 100644
--- a/actionpack/lib/action_dispatch/http/parameters.rb
+++ b/actionpack/lib/action_dispatch/http/parameters.rb
@@ -35,6 +35,10 @@ module ActionDispatch
         @env["action_dispatch.request.path_parameters"] ||= {}
       end
 
+      def reset_parameters #:nodoc:
+        @env.delete("action_dispatch.request.parameters")
+      end
+
     private
 
       # TODO: Validate that the characters are UTF-8. If they aren't,
diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
index 796e0dbc45..9748956052 100644
--- a/actionpack/lib/action_dispatch/http/request.rb
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -6,6 +6,7 @@ require 'active_support/core_ext/hash/indifferent_access'
 require 'active_support/core_ext/string/access'
 require 'active_support/inflector'
 require 'action_dispatch/http/headers'
+require 'action_dispatch/request/session'
 require 'action_controller/metal/exceptions'
 
 module ActionDispatch
@@ -220,11 +221,11 @@ module ActionDispatch
     end
 
     def session=(session) #:nodoc:
-      @env['rack.session'] = session
+      Session.set @env, session
     end
 
     def session_options=(options)
-      @env['rack.session.options'] = options
+      Session::Options.set @env, options
     end
 
     # Override Rack's GET method to support indifferent access