Active Storage purge method throws undefined method signed_id for NilClass

Question

I have a problem similar to the question here but dropping the database isn't a viable solution for my project: Rails 5.2 ActiveStorage undefined method `signed_id' for nil:NilClass

I have a form that allows to upload new images and delete ones that are already uploaded by clicking a link. The form uses Ruby on Rails Active Storage and S3. I followed the answer here to create the link that users can click to delete an image. I think it is deleting the image. However, when the page reloads I get this error

Error: Can't resolve image into URL: undefined method `signed_id' for nil:NilClass

After clicking the "Remove" link, the page should reload and show the remaining images. How do I resolve this error?

Here is the model

class Space < ApplicationRecord
  belongs_to :user

  has_many_attached :space_image

end

The controller

class SpacesController < ApplicationController
  before_action :set_space, except: [:index, :new, :create, :delete_image_attachment]
  before_action :authenticate_user!, except: [:show]


  def delete_image_attachment
    @space_image = ActiveStorage::Blob.find_signed(params[:id])
    @space_image.purge_later
    redirect_back(fallback_location: spaces_path)
  end


  private
    def set_space
      @space = Space.find(params[:id])
    end
end

The view

<div>
  <% if @space.space_image.attached? %>
    <% @space.space_image.each do |space_image| %>
    <%= image_tag space_image, class: "avatar-medium" %>
    <%= link_to 'Remove', delete_image_attachment_space_url(space_image.signed_id),
                method: :delete,
                  data: { confirm: 'Are you sure?' } %>
    <% end %>
  <% end %>
</div>

** Server error output **

ActionView::Template::Error (Can't resolve image into URL: undefined method `signed_id' for nil:NilClass):
    1: <div>
    2:   <% if @space.space_image.attached? %>
    3:     <% @space.space_image.each do |space_image| %>
    4:     <%= image_tag space_image, class: "avatar-medium" %>
    5:     <%= link_to 'Remove', delete_image_attachment_space_url(space_image.signed_id),
    6:                 method: :delete,
    7:                   data: { confirm: 'Are you sure?' } %>

app/views/spaces/_spaceimg.html.erb:4:in `block in _app_views_spaces__spaceimg_html_erb___4211978368865358240_70218939472720'
app/views/spaces/_spaceimg.html.erb:3:in `_app_views_spaces__spaceimg_html_erb___4211978368865358240_70218939472720'
app/views/spaces/listing.html.erb:121:in `block in _app_views_spaces_listing_html_erb__2591928334825339114_70218934956920'
app/views/spaces/listing.html.erb:15:in `_app_views_spaces_listing_html_erb__2591928334825339114_70218934956920'

iGian iGian · Accepted Answer · 2018-09-04T17:38:53

This happens because you deleted a record directly from ActiveStorage::Blob, in this way you broke the consistency.

Instead you must find the related record in ActiveStorage::Attachment then delete it: see this line.

Edit:

Tested in console, so maybe you need to fix some syntax.

space_image.id should return the id of the record in ActiveStorage::Attachment, so pass it to the controller:

delete_image_attachment_space_url(space_image.id)

Then in controller, just find the record and apply the method you need to delete it:

  def delete_image_attachment
    @space_image = ActiveStorage::Attachment.find(params[:id])
    @space_image.purge
    # whatever
  end

Active Storage purge method throws undefined method signed_id for NilClass

1 Answers