Question

Based on Railscast 196 and 197, I’ve created a nested form for adding multiple illustrations (image attachments) to my article model. I have a form like this:

<%= form_for @article, :html => { :multipart => true } do |f| %>  
  <h2>Illustrations</h2>
  <% for illustration in @article.illustrations %>    
    <%= f.fields_for :illustrations, illustration do |builder| %>  
       <%= render :partial => "illustration_fields", 
         :locals => { :f => builder, :illustration => illustration } %>
    <% end %>
  <% end %>
  <p>  
    <%= f.submit "Submit" %>  
  </p>
<% end %>

And the _illustration_fields partial looks like this:

<div class="fields">
  <p>
    <%= f.label :illustration, "Illustration" %><br />
    <%= link_to_remove_fields "remove", f %><br />
    <%= f.file_field :illustration %>  
  </p>
</div>

If the illustration already exists, I want to display it on the page inside an image tag. I tried displaying the image inside the partial like this:

<% unless :illustration.illustration.blank? %>
   <%= image_tag(:illustration.illustration.url) %>
<% end %>

But it throws up an error:

undefined method `illustration' for :illustration:Symbol

The illustration field definitely exists in the illustration model, as I can display the image inside the main form like this:

<% unless illustration.illustration.blank? %>
  <%= image_tag(illustration.illustration.url) %>
<% end %>

It seems that Rails doesn’t understand the illustration information into the partial (or I’m not passing it correctly). What is the correct approach to going about this?

Answer 1

Solved it. The illustration object can be accessed from inside the partial as follows. No need to pass it inside the :locals hash.

<% unless f.object.illustration.blank? %>
  <%= image_tag(f.object.illustration.url) %>
<% end %>