Question

I have a nested form in which I would like the form fields to only appear once for uploading a new image, then display the existing images, without any sort of CRUD capability. In essence, on the edit page, just give the option to add images, but not delete or update.

The relationship is a video has many video_images, which use paperclip for has_attached_file :image I’m trying the following in my controller now:

  # GET /videos/new
  # GET /videos/new.json
  def new
    @video = current_user.videos.build
    @newthumbnail = @video.video_images.build

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @video }
    end
  end

And this in my view:

    <%= f.fields_for @newthumbnail do |u| %>
        <%= u.label :image, "Upload New Thumbnail" %> <br />
        <%= u.file_field :image, :class => "image_uploader" %>
    <% end %>
    <p>
      Or select a previous thumbnail
    </p>
    <div id="previous_thumbnails">
      <!-- These will ultimately be dynamically generated as the existing image associations -->
      <div class="previous_thumbnail" rel="1">
        <img src="http://placehold.it/120x90" />
      </div>
      <div class="selected previous_thumbnail" rel="2">
        <img src="http://placehold.it/120x90" />
      </div>
      <div class="previous_thumbnail" rel="3">
        <img src="http://placehold.it/120x90" />
      </div>
      <div class="previous_thumbnail" rel="4">
        <img src="http://placehold.it/120x90" />
      </div>
    </div>

But I end up with the following error:

unknown attribute: video_image

Which tells me that somewhere, there’s a mistranslation of singularity vs plurality. I can see why Rails would singularize it, as it is, in fact, a single entry. However, even overriding the name of the file field, and making name="video[video_image][image]" into name="video[video_images][image]", I get an error like so:

VideoImage(#39741260) expected, got Array(#9591480)

With params sent:

"video_images"=>{"image"=>#<ActionDispatch::Http::UploadedFile:0x000000054f1078 @original_filename="Bill OneManBand.jpg",
 @content_type="image/jpeg",
 @headers="Content-Disposition: form-data; name=\"video[video_images][image]\"; filename=\"Bill OneManBand.jpg\"\r\nContent-Type: image/jpeg\r\n",
 @tempfile=#<File:/tmp/RackMultipart20120205-3582-1xp2duq>>},

So where am I going wrong? I feel like I may be taking the wrong approach to this…

Answer 1

Change this

<%= f.fields_for @newthumbnail do |u| %>

to this

<%= f.fields_for :video_images, @newthumbnail do |u| %>

That should let the fields know that they’re part of the video and not just random video_image fields

Also make sure you have accepts_nested_attributes_for in your video model.