Best practice for showing errors AND updating list


Morning/Afternoon/Evening All,

This is my first post to the ruby message board so if my request is
better suited to another location just let me know,

The problem I keep coming up against is with a listing of objects and
updating that list via AJAX (for arguments we are talking about a list
of users).

As it stands I can currently submit a form, and update the list
(using :update => ‘list_div_name’ and generating the whole list again or
generating a partial of a single row and using Insertion.Top) and I can
also display the errors for a form using the same method and updating a
notification div above my form,

However, my problem occurs when I want to update a list on success
and display errors on failure,

I have figured the best way up until now would be to always update
the forms notification and either display the errors or generate a
hidden div and copy its contents to the top of the list if successful
but this seems far from efficient,

What I am essentially asking is there a standard / more efficient way
of doing this that I have missed completely or is my current method

  • Michael


Michael B. wrote:

However, my problem occurs when I want to update a list on success
and display errors on failure,

Look at the :success and :failure parameters of link_to_remote,
which can also be inside the :update parameter. Also available in
submit_to_remote, form_remote_tag, periodically_call_remote,
remote_function, observe_field, and observe_form:

Set the reponse status in your controller using the :status parameter
to render:

We develop, watch us RoR, in numbers too big to ignore.


Using RJS (requires rails trunk) is probably the simplest way, you can
then control which parts of the page are updated. Your action may

def add_user
@user = User.create(params[:user])

And add_user.rjs:

if @user.valid?
page.insert_html :top, ‘user_list’, :partial => ‘user’, :object =>
page.replace_html ‘errors’, :partial => ‘errors’, :object =>

Make sure you remove the :update => bit from your helper call as well.
You can actually now put the RJS in the controller if you like…

def add_user

render :update do |page|
if @user

Whatever takes your fancy :slight_smile:

Cheers, -Jonny.


Thanks guys :slight_smile: that told me exactly what I was after


Quick note, there is actually a plugin to allow you to use RJS outside
of the Trunk release. Can’t remember the site, but do a quick google
for it and you’ll run across it. Works great for me.