2 files changed, 51 insertions, 0 deletions
diff --git a/actionpack/lib/action_dispatch/request/session.rb b/actionpack/lib/action_dispatch/request/session.rb
index a05a23d953..973627f106 100644
--- a/actionpack/lib/action_dispatch/request/session.rb
+++ b/actionpack/lib/action_dispatch/request/session.rb
@@ -7,6 +7,9 @@ module ActionDispatch
       ENV_SESSION_KEY         = Rack::Session::Abstract::ENV_SESSION_KEY # :nodoc:
       ENV_SESSION_OPTIONS_KEY = Rack::Session::Abstract::ENV_SESSION_OPTIONS_KEY # :nodoc:
 
+      # Singleton object used to determine if an optional param wasn't specified
+      Unspecified = Object.new
+
       def self.create(store, env, default_options)
         session_was = find env
         session     = Request::Session.new(store, env)
@@ -63,6 +66,10 @@ module ActionDispatch
         @exists   = nil # we haven't checked yet
       end
 
+      def id
+        options[:id]
+      end
+
       def options
         Options.find @env
       end
@@ -123,6 +130,15 @@ module ActionDispatch
         @delegate.delete key.to_s
       end
 
+      def fetch(key, default=Unspecified, &block)
+        load_for_read!
+        if default == Unspecified
+          @delegate.fetch(key.to_s, &block)
+        else
+          @delegate.fetch(key.to_s, default, &block)
+        end
+      end
+
       def inspect
         if loaded?
           super
diff --git a/actionpack/lib/action_dispatch/request/utils.rb b/actionpack/lib/action_dispatch/request/utils.rb
new file mode 100644
index 0000000000..9d4f1aa3c5
--- /dev/null
+++ b/actionpack/lib/action_dispatch/request/utils.rb
@@ -0,0 +1,35 @@
+module ActionDispatch
+  class Request < Rack::Request
+    class Utils # :nodoc:
+
+      mattr_accessor :perform_deep_munge
+      self.perform_deep_munge = true
+
+      class << self
+        # Remove nils from the params hash
+        def deep_munge(hash, keys = [])
+          return hash unless perform_deep_munge
+
+          hash.each do |k, v|
+            keys << k
+            case v
+            when Array
+              v.grep(Hash) { |x| deep_munge(x, keys) }
+              v.compact!
+              if v.empty?
+                hash[k] = nil
+                ActiveSupport::Notifications.instrument("deep_munge.action_controller", keys: keys)
+              end
+            when Hash
+              deep_munge(v, keys)
+            end
+            keys.pop
+          end
+
+          hash
+        end
+      end
+    end
+  end
+end
+