Active Storage attachment - Can't resolve image into URL: undefined method `attachment_url

Question

A similar question has been asked but none of the solutions have worked for me. Im building an app in solidus and need to generate qr codes for each time a product is created. Im using the rqr gem and then trying to attach the generated rqrcode png to a product in Active Storage.

I am getting the following error whenever im trying to render the image.

Can't resolve image into URL: undefined method `attachment_url' for #<ActionView::Base:0x007fd104542310>

<%= image_tag(@product.qr_code) if @product.qr_code.attached? %>

When a product gets created I generate a qr_code in the model like this.

has_one_attached :qr_code
after_create :generate_qr
   
    def generate_qr
      qrcode = RQRCode::QRCode.new("localhost:3000/products/#{self.slug}")
      # NOTE: showing with default options specified explicitly
      png = qrcode.as_png(
        bit_depth: 1,
        border_modules: 4,
        color_mode: ChunkyPNG::COLOR_GRAYSCALE,
        color: "black",
        file: nil,
        fill: "white",
        module_px_size: 6,
        resize_exactly_to: false,
        resize_gte_to: false,
        size: 120
      )

      image_name = SecureRandom.hex
      IO.binwrite("tmp/#{image_name}.png", png.to_s)
      
      blob = ActiveStorage::Blob.create_after_upload!(
        io: File.open("tmp/#{image_name}.png"),
        filename: image_name,
        content_type: 'png'
      )

      self.qr_code.attach(blob)
    end

I've also tried attaching directly with the attach method

 self.qr_code.attach(
         io: File.open("tmp/#{image_name}.png"),
         filename: image_name,
         content_type: 'png'
       )

When I run @product.qr_code.attached? I get true so I know the Active Record attaching is working.

I have checked all my all my config files and everything seems to be correct.

config/storage.yml

test:
  service: Disk
  root: <%= Rails.root.join("tmp/storage") %>

local:
  service: Disk
  root: <%= Rails.root.join("storage") %>

config.active_storage.service = :local <--- congif/enivronments/development.rb
config.active_storage.service = :local<--- congif/enivronments/production.rb
config.active_storage.service = :test <--- congif/enivronments/test.rb

Does anyone know what could be causing this error message? Thanks.

Please add the versions you are using (Ruby, Rails, Solidus). Thanks! — wintermeyer, Feb 15 '22 at 09:01

score 1 · Answer 1 · edited Feb 16 '22 at 10:35

I was able to reproduce your issue and found that you can render the QR code of the product by getting the URL of the QR code from its representation object:

<%= image_tag(@product.qr_code.representation(
    resize_to_limit: [100, 100]).processed.url) %>

Please see https://edgeguides.rubyonrails.org/active_storage_overview.html#lazy-vs-immediate-loading for more details.

This was how I overrode the Product model:

# app/overrides/store/product/can_generate_qr.rb
module Store
  module Spree
    module Product
      module CanGenerateQR
        def self.prepended(base)
          base.has_one_attached :qr_code
          base.after_create :generate_qr
        end

        def generate_qr
          qrcode = RQRCode::QRCode.new("localhost:3000/products/#{self.slug}")
          # NOTE: showing with default options specified explicitly
          png = qrcode.as_png(
            bit_depth: 1,
            border_modules: 4,
            color_mode: ChunkyPNG::COLOR_GRAYSCALE,
            color: "black",
            file: nil,
            fill: "white",
            module_px_size: 6,
            resize_exactly_to: false,
            resize_gte_to: false,
            size: 120
          )

          image_name = SecureRandom.hex
          IO.binwrite("tmp/#{image_name}.png", png.to_s)

          blob = ActiveStorage::Blob.create_after_upload!(
            io: File.open("tmp/#{image_name}.png"),
            filename: image_name,
            content_type: 'png'
          )

          self.qr_code.attach(blob)
        end

        ::Spree::Product.prepend self
      end
    end
  end
end

Active Storage attachment - Can't resolve image into URL: undefined method `attachment_url

1 Answers1