```ruby
module Remotipart

  # A middleware to look for our form parameters and
  # encourage Rails to respond with the requested format
  class Middleware
    def initialize app
      @app = app
    end

    def call env
      # Get request params
      begin
        params = Rack::Request.new(env).params
      rescue TypeError => e
        ::Rails.logger.warn e.message
        ::Rails.logger.warn e.backtrace.join("\n")
      end

      if params
        # This was using an iframe transport, and is therefore an XHR
        # This is required if we're going to override the http_accept
        if params['X-Requested-With'] == 'IFrame'
          env['HTTP_X_REQUESTED_WITH'] = 'xmlhttprequest'
        end

        # Override the accepted format, because it isn't what we really want
        if params['X-Http-Accept']
          env['HTTP_ACCEPT'] = params['X-Http-Accept']
        end
      end

      @app.call(env)
    end
  end
end
```

Update HTTP_ACCEPT for jquery.iframe-transport update
user
```ruby
module Remotipart

  # A middleware to look for our form parameters and
  # encourage Rails to respond with the requested format
  class Middleware
    def initialize app
      @app = app
    end

    def call env
      # Get request params
      begin
        params = Rack::Request.new(env).params
      rescue TypeError => e
        ::Rails.logger.warn e.message
        ::Rails.logger.warn e.backtrace.join("\n")
      end

      if params
        # This was using an iframe transport, and is therefore an XHR
        # This is required if we're going to override the http_accept
        if params['X-Requested-With'] == 'IFrame'
          env['HTTP_X_REQUESTED_WITH'] = 'xmlhttprequest'
        end

        # Override the accepted format, because it isn't what we really want
        if params['X-HTTP-Accept']
          env['HTTP_ACCEPT'] = params['X-HTTP-Accept']
        end
      end

      @app.call(env)
    end
  end
end
```
assistant