Implement ActiveStorage::Attached::{One,Many}#attach in terms of changes

4 files changed, 30 insertions, 18 deletions

diff --git a/activestorage/lib/active_storage/attached/changes/create_many.rb b/activestorage/lib/active_storage/attached/changes/create_many.rb
index 3f7ca6a25f..af19328a61 100644
--- a/activestorage/lib/active_storage/attached/changes/create_many.rb
+++ b/activestorage/lib/active_storage/attached/changes/create_many.rb
@@ -12,6 +12,10 @@ module ActiveStorage
       @attachments ||= subchanges.collect(&:attachment)
     end
 
+    def blobs
+      @blobs ||= subchanges.collect(&:blob)
+    end
+
     def upload
       subchanges.each(&:upload)
     end
diff --git a/activestorage/lib/active_storage/attached/changes/create_one.rb b/activestorage/lib/active_storage/attached/changes/create_one.rb
index 98aea36861..5812fd2b08 100644
--- a/activestorage/lib/active_storage/attached/changes/create_one.rb
+++ b/activestorage/lib/active_storage/attached/changes/create_one.rb
@@ -1,5 +1,8 @@
 # frozen_string_literal: true
 
+require "action_dispatch"
+require "action_dispatch/http/upload"
+
 module ActiveStorage
   class Attached::Changes::CreateOne #:nodoc:
     attr_reader :name, :record, :attachable
diff --git a/activestorage/lib/active_storage/attached/many.rb b/activestorage/lib/active_storage/attached/many.rb
index 073cc013d8..25f88284df 100644
--- a/activestorage/lib/active_storage/attached/many.rb
+++ b/activestorage/lib/active_storage/attached/many.rb
@@ -12,19 +12,26 @@ module ActiveStorage
       change.present? ? change.attachments : record.public_send("#{name}_attachments")
     end
 
-    # Associates one or several attachments with the current record, saving them to the database.
+    # Returns all attached blobs.
+    def blobs
+      change.present? ? change.blobs : record.public_send("#{name}_blobs")
+    end
+
+    # Attaches one or more +attachables+ to the record.
+    #
+    # If the record is persisted and unchanged, the attachments are saved to
+    # the database immediately. Otherwise, they'll be saved to the DB when the
+    # record is next saved.
     #
     #   document.images.attach(params[:images]) # Array of ActionDispatch::Http::UploadedFile objects
     #   document.images.attach(params[:signed_blob_id]) # Signed reference to blob from direct upload
     #   document.images.attach(io: File.open("/path/to/racecar.jpg"), filename: "racecar.jpg", content_type: "image/jpg")
     #   document.images.attach([ first_blob, second_blob ])
     def attach(*attachables)
-      attachables.flatten.collect do |attachable|
-        if record.new_record?
-          attachments.build(record: record, blob: create_blob_from(attachable))
-        else
-          attachments.create!(record: record, blob: create_blob_from(attachable))
-        end
+      if record.persisted? && !record.changed?
+        record.update(name => blobs + attachables.flatten)
+      else
+        record.public_send("#{name}=", blobs + attachables.flatten)
       end
     end
 
diff --git a/activestorage/lib/active_storage/attached/one.rb b/activestorage/lib/active_storage/attached/one.rb
index 4a6bb1ffaa..c039226fcd 100644
--- a/activestorage/lib/active_storage/attached/one.rb
+++ b/activestorage/lib/active_storage/attached/one.rb
@@ -17,17 +17,21 @@ module ActiveStorage
       !attached?
     end
 
-    # Associates a given attachment with the current record, saving it to the database.
+    # Attaches an +attachable+ to the record.
+    #
+    # If the record is persisted and unchanged, the attachment is saved to
+    # the database immediately. Otherwise, it'll be saved to the DB when the
+    # record is next saved.
     #
     #   person.avatar.attach(params[:avatar]) # ActionDispatch::Http::UploadedFile object
     #   person.avatar.attach(params[:signed_blob_id]) # Signed reference to blob from direct upload
     #   person.avatar.attach(io: File.open("/path/to/face.jpg"), filename: "face.jpg", content_type: "image/jpg")
     #   person.avatar.attach(avatar_blob) # ActiveStorage::Blob object
     def attach(attachable)
-      new_blob = create_blob_from(attachable)
-
-      if !attached? || new_blob != blob
-        write_attachment build_attachment(blob: new_blob)
+      if record.persisted? && !record.changed?
+        record.update(name => attachable)
+      else
+        record.public_send("#{name}=", attachable)
       end
     end
 
@@ -68,12 +72,6 @@ module ActiveStorage
     end
 
     private
-      delegate :transaction, to: :record
-
-      def build_attachment(blob:)
-        Attachment.new(record: record, name: name, blob: blob)
-      end
-
       def write_attachment(attachment)
         record.public_send("#{name}_attachment=", attachment)
       end