cache request object

lib/sinatra/base.rb

@@ -11,6 +11,10 @@ module Sinatra
   # The request object. See Rack::Request for more info:
   # http://rack.rubyforge.org/doc/classes/Rack/Request.html
   class Request < Rack::Request
+    def self.new(env)
+      env['sinatra.request'] ||= super
+    end
+
     # Returns an array of acceptable media types for the response
     def accept
       @env['sinatra.accept'] ||= begin