AJAX and REST: rendering partials

rubyonrails-talk
1

Hi, I have an Items resource and each Item has an attribute 'starred'. The items/index page shows a list of items, each one is in its own partial and has an image of a star (star_off.gif) next to it. When the star is clicked, an AJAX PUT request is made to the Update action. The starred attribute is updated and a the items partial is replaced so that star_on.gif is shown. So far so good, the code is below:

#### _item.html.erb <tr id="item_<%= item.id %>">   <td>     <% if item.starred?%>     <%= link_to_remote image_tag('star_on.gif',:class => 'star'),                        :url => item_url(item),                        :with => "'item[starred]=false'",                        :method => :put

     %>     <% else %>       <%= link_to_remote image_tag('star_off.gif',:class => 'star'),                          :url => item_url(item),                          :with => "'item[starred]=true'",                          :method => :put        %>     <%end%>     <%= link_to item.name, item_path(item) %>   </td> <tr/>

#### items_controller def update   @item = Item.find(params[:id])   respond_to do |format|     if @item.update_attributes(params[:item])       format.js {render :update do |page|                     page.replace "item_#{@item.id}", :partial => 'shared/item', :locals => {:item => @item}                   end}     else     end   end end

The problem comes when I am working on the show.html.erb page. This page shows the details of the item. I want show the star on this page too and have the same functionality, i.e. the stars state changes when the image is clicked. However, the controller is coded to render the shared/item partial when a javascript request is received, this is not what I want on the show page. The _item.html.erb is for the index page, I do not want to render this when the request comes from the show page.

Am I approaching the AJAX calls in the correct way here? The partial that needs to be rendered after the update action is dependent on where the AJAX call is made from. How is this done, or am I doing something completely wrong? Thanks

2

Hi Tim,

Tim Conner wrote:

The partial that needs to be rendered after the update action is dependent on where the AJAX call is made from.

The easy way to handle this is simply to pass a param, probably via a hidden_field_tag, that tells you from which partial the method was called. There's nothing unRESTful about this. The only downside is that it'll push you to do your rendering in the controller rather than just letting Rails render the default view. Nothing really wrong with that either though. The method will look something like...

def update    respond_to do |format|       format.js {          if params[:called_from] == 'show'             render_update do |page|                 page.replace_html ...             end          elsif params[:called_from] == 'list'             render_update do |page|                 page.replace_html ... something else             end          else              #might want to do some error trapping here          end        }     end end

HTH, Bill

3

Thanks for the help, I have implemented it in the way you suggested.