Add RewindableInput wrapper to fix issues with middleware that impolitely eat up non-rewindable input

2 files changed, 41 insertions, 0 deletions

diff --git a/actionpack/lib/action_controller/middlewares.rb b/actionpack/lib/action_controller/middlewares.rb
index 793739723f..914750bc0c 100644
--- a/actionpack/lib/action_controller/middlewares.rb
+++ b/actionpack/lib/action_controller/middlewares.rb
@@ -18,4 +18,5 @@ use "ActiveRecord::QueryCache", :if => lambda { defined?(ActiveRecord) }
     )
 end
 
+use ActionController::RewindableInput
 use ActionController::VerbPiggybacking
diff --git a/actionpack/lib/action_controller/rewindable_input.rb b/actionpack/lib/action_controller/rewindable_input.rb
new file mode 100644
index 0000000000..296d8aed22
--- /dev/null
+++ b/actionpack/lib/action_controller/rewindable_input.rb
@@ -0,0 +1,40 @@
+module ActionController
+  class RewindableInput
+    class RewindableIO < ActiveSupport::BasicObject
+      def initialize(io)
+        @io = io
+      end
+
+      def read(*args)
+        read_original_io
+        @io.read(*args)
+      end
+
+      def rewind
+        read_original_io
+        @io.rewind
+      end
+
+      def method_missing(method, *args, &block)
+        @io.send(method, *args, &block)
+      end
+
+      private
+        def read_original_io
+          unless @str
+            @str = @io.read
+            @io = StringIO.new(@str)
+          end
+        end
+    end
+
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      env['rack.input'] = RewindableIO.new(env['rack.input'])
+      @app.call(env)
+    end
+  end
+end