I migrated the actionwebservice gem to rails3. Inside actionwebservice (server-side) there is the option to test your SOAP interface. What this does, under the cover, is first handle the SOAP-request (and render the result), and then wrap those results inside a HTML-view. Very nice. To circumvent the double render exception in rails2 you had to call a function erase_render_results.

Unfortunately this function is no longer available in rails3. Luckily the fix is quite easy (but it took me a while to find).

Inside actionwebservice the following function was called inside a controller to allow a second render:

  def reset_invocation_response
    response.instance_variable_set :@header, Rack::Utils::HeaderHash.new(::ActionController::Response::DEFAULT_HEADERS.merge("cookie" => []))

To make this work in rails3, you just have to write:

  def reset_invocation_response
    self.instance_variable_set(:@_response_body, nil)
    response.instance_variable_set :@header, Rack::Utils::HeaderHash.new("cookie" => [], 'Content-Type' => 'text/html')

So in short: to allow a second render, you have to

  • set the controller’s instance variable @_response_body to nil
  • reset the content-header

Hope this helps.