Store images with Active Storage as well

While we migrate from Paperclip to Active Storage, we need to use both
at the same time to avoid any downtime or lost images.

Once the migration is complete, we want to use the same name for
attachment as before. Using Paperclip and Active Storage at the same
time creates a name conflict on a couple of methods.

I'm using alias_method as a temporary solution to access Active Storage
methods. We will remove that after the migration. I declare Paperclip
afterwards so that we have those methods declarations for backwards
compatibility now.

app/models/spree/image.rb

@@ -7,6 +7,17 @@ module Spree
     validates_attachment_presence :attachment
     validate :no_attachment_errors
 
+    # Active Storage declaration
+    has_one_attached :attachment
+
+    # Backup Active Storage methods before they get overridden by Paperclip.
+    alias_method :active_storage_attachment, :attachment
+    alias_method :active_storage_attachment=, :attachment=
+
+    # Paperclip declaration
+    #
+    # This will define the `name` and `name=` methods as well.
+    #
     # This is where the styles are used in the app:
     # - mini: used in the BackOffice: Bulk Product Edit page and Order Cycle edit page
     # - small: used in the FrontOffice: Product List page
@@ -21,6 +32,18 @@ module Spree
                       path: ':rails_root/public/spree/products/:id/:style/:basename.:extension',
                       convert_options: { all: '-strip -auto-orient -colorspace sRGB' }
 
+    after_post_process do
+      if attachment.errors.blank?
+        attachable = {
+          io: File.open(local_filename_of_original),
+          filename: attachment_file_name,
+          content_type: attachment_content_type,
+          identify: false,
+        }
+        self.active_storage_attachment = attachable
+      end
+    end
+
     # save the w,h of the original image (from which others can be calculated)
     # we need to look at the write-queue for images which have not been saved yet
     after_post_process :find_dimensions

config/storage.yml

@@ -6,6 +6,13 @@ test:
   service: Disk
   root: <%= Rails.root.join("tmp/storage") %>
 
+test_amazon:
+  service: S3
+  access_key_id: "A...A"
+  secret_access_key: "H...H"
+  bucket: "ofn"
+  region: "us-east-1"
+
 amazon:
   service: S3
   access_key_id: <%= ENV["S3_ACCESS_KEY"] %>

spec/models/spree/image_spec.rb

@@ -21,6 +21,18 @@ module Spree
         expect(attachment.file?).to eq true
         expect(attachment.url).to match %r"^/spree/products/[0-9]+/product/logo-black\.png\?[0-9]+$"
       end
+
+      it "duplicates the image with Active Storage" do
+        image = Spree::Image.create!(
+          attachment: file,
+          viewable: product.master,
+        )
+
+        attachment = image.active_storage_attachment
+        url = Rails.application.routes.url_helpers.url_for(attachment)
+
+        expect(url).to match %r|^http://test\.host/rails/active_storage/blobs/redirect/[[:alnum:]-]+/logo-black\.png$|
+      end
     end
 
     describe "using AWS S3" do
@@ -47,9 +59,12 @@ module Spree
         allow(Spree::Image).to receive(:attachment_definitions).and_return(
           attachment: attachment_definition.merge(s3_config)
         )
+        allow(Rails.application.config.active_storage).
+          to receive(:service).and_return(:test_amazon)
       end
 
       it "saves a new image when none is present" do
+        # Paperclip requests
         upload_pattern = %r"^https://ofn.s3.amazonaws.com/[0-9]+/(original|mini|small|product|large)/logo-black.png$"
         download_pattern = %r"^https://ofn.s3.amazonaws.com/[0-9]+/product/logo-black.png$"
         public_url_pattern = %r"^https://ofn.s3.us-east-1.amazonaws.com/[0-9]+/product/logo-black.png\?[0-9]+$"
@@ -57,15 +72,27 @@ module Spree
         stub_request(:put, upload_pattern).to_return(status: 200, body: "", headers: {})
         stub_request(:head, download_pattern).to_return(status: 200, body: "", headers: {})
 
+        # Active Storage requests
+        as_upload_pattern = %r"^https://ofn.s3.amazonaws.com/[[:alnum:]]+$"
+
+        stub_request(:put, as_upload_pattern).to_return(status: 200, body: "", headers: {})
+
         image = Spree::Image.create!(
           attachment: file,
           viewable: product.master,
         )
 
+        # Paperclip
         attachment = image.attachment
         expect(attachment.exists?).to eq true
         expect(attachment.file?).to eq true
         expect(attachment.url).to match public_url_pattern
+
+        # Active Storage
+        attachment = image.active_storage_attachment
+        expect(attachment).to be_attached
+        expect(Rails.application.routes.url_helpers.url_for(attachment)).
+          to match %r"^http://test\.host/rails/active_storage/blobs/redirect/[[:alnum:]-]+/logo-black\.png"
       end
     end
   end