Add experimental TimeZone middleware

lib/rack/contrib.rb

@@ -14,4 +14,5 @@ def self.release
   autoload :MailExceptions,             "rack/mailexceptions"
   autoload :PostBodyContentTypeParser,  "rack/post_body_content_type_parser"
   autoload :Sendfile,                   "rack/sendfile"
+  autoload :TimeZone,                   "rack/time_zone"
 end

lib/rack/time_zone.rb

@@ -0,0 +1,25 @@
+module Rack
+  class TimeZone
+    Javascript = <<-EOJ
+    function setTimezoneCookie() {
+      var offset = (new Date()).getTimezoneOffset()
+      var date = new Date();
+      date.setTime(date.getTime()+3600000);
+      document.cookie = "utc_offset="+offset+"; expires="+date.toGMTString();+"; path=/";
+    }
+EOJ
+
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      request = Rack::Request.new(env)
+      if utc_offset = request.cookies["utc_offset"]
+        env["rack.timezone.utc_offset"] = -(utc_offset.to_i * 60)
+      end
+
+      @app.call(env)
+    end
+  end
+end