optimize templates api

app/controllers/api/templates_controller.rb

@@ -7,10 +7,31 @@ module Api
     def index
       templates = filter_templates(@templates, params)
 
-      templates = paginate(templates.preload(:author, documents_attachments: :blob))
+      templates = paginate(templates.preload(:author, :folder))
+
+      schema_documents =
+        ActiveStorage::Attachment.where(record_id: templates.map(&:id),
+                                        record_type: 'Template',
+                                        name: :documents,
+                                        uuid: templates.flat_map { |t| t.schema.pluck('attachment_uuid') })
+                                 .preload(:blob)
+
+      preview_image_attachments =
+        ActiveStorage::Attachment.joins(:blob)
+                                 .where(blob: { filename: '0.jpg' })
+                                 .where(record_id: schema_documents.map(&:id),
+                                        record_type: 'ActiveStorage::Attachment',
+                                        name: :preview_images)
+                                 .preload(:blob)
 
       render json: {
-        data: templates.as_json(serialize_params),
+        data: templates.map do |t|
+          Templates::SerializeForApi.call(
+            t,
+            schema_documents.select { |e| e.record_id == t.id },
+            preview_image_attachments
+          )
+        end,
         pagination: {
           count: templates.size,
           next: templates.last&.id,
@@ -20,7 +41,7 @@ module Api
     end
 
     def show
-      render json: @template.as_json(serialize_params)
+      render json: Templates::SerializeForApi.call(@template)
     end
 
     def update
@@ -61,14 +82,6 @@ module Api
       templates
     end
 
-    def serialize_params
-      {
-        methods: %i[application_key],
-        include: { author: { only: %i[id email first_name last_name] },
-                   documents: { only: %i[id uuid], methods: %i[url preview_image_url filename] } }
-      }
-    end
-
     def template_params
       permit_params = [
         :name,

config/initializers/active_storage.rb

@@ -8,14 +8,6 @@ ActiveSupport.on_load(:active_storage_attachment) do
   def signed_uuid
     @signed_uuid ||= ApplicationRecord.signed_id_verifier.generate(uuid, expires_in: 6.hours, purpose: :attachment)
   end
-
-  def preview_image_url
-    first_page = preview_images.joins(:blob).find_by(blob: { filename: '0.jpg' })
-
-    return unless first_page
-
-    ActiveStorage::Blob.proxy_url(first_page.blob)
-  end
 end
 
 ActiveSupport.on_load(:active_storage_blob) do

lib/templates/serialize_for_api.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Templates
+  module SerializeForApi
+    module_function
+
+    def call(template, schema_documents = template.schema_documents, preview_image_attachments = [])
+      json = template.as_json(
+        methods: %i[application_key],
+        include: { author: { only: %i[id email first_name last_name] } }
+      )
+
+      json[:folder_name] = template.folder.name
+
+      json[:documents] = template.schema.map do |item|
+        attachment = schema_documents.find { |e| e.uuid == item['attachment_uuid'] }
+
+        first_page_blob = preview_image_attachments.find { |e| e.record_id == attachment.id }&.blob
+        first_page_blob ||= attachment.preview_images.joins(:blob).find_by(blob: { filename: '0.jpg' })&.blob
+
+        {
+          id: attachment.id,
+          uuid: attachment.uuid,
+          url: ActiveStorage::Blob.proxy_url(attachment.blob),
+          preview_image_url: first_page_blob && ActiveStorage::Blob.proxy_url(first_page_blob),
+          filename: attachment.filename
+        }
+      end
+
+      json
+    end
+  end
+end