Ruby on Rails：在嵌套模型上正确使用带有载波的image_tag

Question

I have partial named _userbox, which displays data grabbed from the user model. I also have a seperate image model, which stores information about images.

class User
  ...
  has_many :images, :dependent => :destroy  
  accepts_nested_attributes_for :images, allow_destroy: true    
  ...
end

class Image
  ...
  attr_accessible :image_priority, :image_title, :image_location
  belongs_to :user
  mount_uploader :image_location, ProfilePictureUploader
  ...
end

_userbox.html.erb
    <% @users.each do |user| %>     
      <tr>
        <td><%= image_tag user.images.image_location.url.to_s %></td>
        <td valign="top">
          <p><%= link_to user.first_name, user_path(user) %></p>
          <p><%= age(user.date_of_birth) %> / <%= user.gender %> / <%= user.orientation %></p>
          <p>from <%= user.location %></p>
          <p>Question? Answer answer answer answer answer answer answer</p>
        </td>
      </tr>
    <% end %>

It works fine, except image_tag. I'm using the carrierwave gem to upload image files. The files are uploaded, but I don't know what is the proper way to acesss them in my view. I get error message like: undefined method `image_location' for []:ActiveRecord::Relation

What is the proper way to use that image_tag?

Answer 1

You have has_many :images , so user.images is a relation, not a single Image instance. To show something in your partial, either show the first image, or loop over them:

<% @users.each do |user| %>     
  <tr>
    <td><%= image_tag user.images.first.image_location.url.to_s %></td>
    <td valign="top">... 
    </td>
  </tr>
<% end %>

or loop over them:

<% @users.each do |user| %>     
  <tr>
    <td>
      <% user.images.each do |img| %>
        <%= image_tag img.image_location.url.to_s %>
      <% end %>
    </td>
    <td valign="top">... 
    </td>
  </tr>
<% end %>