Rails - Jun 2005 - Handling Validation Errors With Ajax Enabled Forms

I''ll try and simplify this as best I can.  I have a page layed out as
follows:

-----
| A |
-----
| B |
-----

Div A is a list of items, Div B is an Ajax-enabled form.  

I understand how to submit the form ''B'' and update list
''A'' with the results.

What I can''t seem to do is handle validation errors.  

On an error (any error that invalidates the model), I would like
''B''
to display the form with errors (just like standard scaffolding).  
Upon success, I would like ''A'' to be updated.

Anyone know how to accomplish this without patching Rails?  Am I
missing something?

Thanks as always, 

Michael

OK.. so I think I''ve stumbled upon a conceptual solution, but I need
someone with a better understanding of javascript to tell me if I''m on
the right track.

After processing, Div B will use ''complete'' and call a custom
javascript function to investigate the contents of Div B.  If there is
a validation error, we hang tight.  If there is no error, we clear the
form (or whatever we want to do) and insert the appropriate html in A
by using the prototype functions.

So... does anyone know how to easily use javascript to detect a
validation error within the returned content?

On 6/27/05, Michael Gorsuch
<michael.gorsuch-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> I''ll try and simplify this as best I can.  I have a page layed out
as follows:
> 
> -----
> | A |
> -----
> | B |
> -----
> 
> Div A is a list of items, Div B is an Ajax-enabled form.
> 
> I understand how to submit the form ''B'' and update list
''A'' with the results.
> 
> What I can''t seem to do is handle validation errors.
> 
> On an error (any error that invalidates the model), I would like
''B''
> to display the form with errors (just like standard scaffolding).
> Upon success, I would like ''A'' to be updated.
> 
> Anyone know how to accomplish this without patching Rails?  Am I
> missing something?
> 
> Thanks as always,
> 
> Michael
>

> OK.. so I think I''ve stumbled upon a conceptual solution, but I
need
> someone with a better understanding of javascript to tell me if
I''m on
> the right track.
> 
> After processing, Div B will use ''complete'' and call a
custom
> javascript function to investigate the contents of Div B.  If there is
> a validation error, we hang tight.  If there is no error, we clear the
> form (or whatever we want to do) and insert the appropriate html in A
> by using the prototype functions.
> 
> So... does anyone know how to easily use javascript to detect a
> validation error within the returned content?
The solution that I''ve come up with is to put:

<% if defined? @object %>
 <%= error_messages_for ''object'' %>
<% end %>

at the bottom of "A" (so it looks like it''s the top of
"B").

Then when you submit and it fails, "A" will update and show the
errors,
and the item won''t be added to the list.

The problem I had was clearing the form once a record had been
successfully saved - I have since written
http://www.sinner.co.za/articles/2005/06/28/returning-js-in-a-partial
describing how I fixed that - basically:

controller:
if @object.save
  flash[:saved] = ''true''
end

partial:
<% if @flash[:saved] == ''true'' %>
<script>document.forms[0].reset();</script>
<% end %>

There seem to be quite a few patches adding more elegant solutions to
rails, I hope that they will be integrated into 0.13...

Michael