Rails file upload (paperclip) on edit

I made myself a simple rails blogging-type app where I use Paperclip to upload image files.I have everything working fine and dandy. I even have it hooked up to an S3 bucket, etc. Spiffy right?

But I can't figure what to do when EDITING/UPDATING a post. As is stands now, all I have is this field on my form template:

= f.file_field :image

So, say on "post/5/edit" even if there's a previously attached image, the field displays "No file chosen".

Even worse, there's no apparent way to clear out current image if I change my mind and don't want to attach an image.

How do I make this a little more user-friendly and make sure the current image -- text/url is fine -- shows up as the value in the text field and/or the user can change the current image to none.


For Rails3 here's what I do. Sorry, I haven't used Rails4 yet.

To display to the user if they have already uploaded a file, do this in your view:

<% if @blog.image.exists? %>
  <%= image_tag @blog.image.url(:thumb) %><br/>
<% end %>
<%= f.file_field :image %>

Then, to allow for the user to remove the current upload add this to your view (inside that if block):

<%= f.check_box :delete_image %>Delete Image<br/>

And you handle that checkbox in your model:

  before_validation { image.clear if @delete_image }

  def delete_image
    @delete_image ||= false

  def delete_image=(value)
    @delete_image  = !value.to_i.zero?

That way if the user sets the checkbox it will clear the image on the next save.

The above method didn't work for me with multiple fields.

I'm used javascript to do this as I am also using cocoon to dynamically add multiple images, on the edit form I am displaying all images with their own delete buttons. I then count the number of image objects and hide that same amount of image file upload boxes. I currently have it set for multiple but with just a little change it could work for your case. After delete, they are redirected back where in your case, count would be 0 and it would show the upload box.

This is the nested form section

<h3 class="text-muted">Upload Images</h3>
<% @rental.property_photos.each do |i| %>
    <div class="pic">
        <%= image_tag i.avatar.url(:thumb), class:"img-responsive property-images" %>
        <%= link_to i, method: :delete, data: { confirm: 'Are you sure?' } do %>
        <i class="fa fa-times-circle delete-pic"></i>
        <% end %>
<% end %>
<fieldset id="property_photos">
    <%= f.fields_for :property_photos do |p| %>
    <%= render 'property_photo_fields', :f => p %>
    <% end %>
<div class="links">
    <%= link_to_add_association 'Add Image', f, :property_photos, class:"fa fa-plus margin-bottom-20" %>

My nested form

<div class="nested_fields">
    <div class="col-md-3 picUploader">
         <%= f.file_field :avatar %>

My javascript

$(document).ready(function () {

     var count = $('.pic').length;

     function hideElements(x) {



with a little css your results then look like this...

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