Rails - Aug 2009 - Needed proper structure for a controller null response

I have a situation where a part of a page is under the control of
periodically_call_remote() js helper.  In response, the controller
answers with a render(:partial ...).  When the controller knows that
nothing in the display has changed, I wish to respond with the
equivalent of a ''200 OK'' response.  How can I code that in the
controller?

Hi,

On Sat, 2009-08-01 at 10:59 -0700, explainer wrote:
> I have a situation where a part of a page is under the control of
> periodically_call_remote() js helper.  In response, the controller
> answers with a render(:partial ...).  
I''m not sure I understand your explanation.  

You say you''re using periodically_call_remote which would lead me to
expect that in your controller (assuming that''s where you''re
responding), you''d be using

render :update do |page|
  page.replace_html (or some variation) ...
end

But you say your controller ''answers with a render(:partial ...)

I''ll take a stab below, but if that doesn''t get it please post
relevant
code.
> When the controller knows that
> nothing in the display has changed, I wish to respond with the
> equivalent of a ''200 OK'' response.  How can I code that
in the
> controller?
If you''re returning html, you can just use head (in
ActionController::Base)

return head(:success)
render

I''m not sure how to return just a header with js cause I''ve
never needed
to do it, but the first thing I''d probably try would be:

render :js => ''''

or 

render :js => '''', :status => :success

If for whatever reason those didn''t work, I''d probably create
an empty
element on the page and...

render :update do |page|
  page.replace_html ''empty_element'', ''''
end

HTH,
Bill