optimize for large files

lib/templates/process_document.rb

@@ -9,6 +9,12 @@ module Templates
     PDF_CONTENT_TYPE = 'application/pdf'
     Q = 35
     MAX_WIDTH = 1400
+    MAX_NUMBER_OF_PAGES_PROCESSED =
+      if Docuseal.multitenant?
+        70
+      else
+        40
+      end
 
     module_function
 
@@ -42,14 +48,38 @@ module Templates
 
     def generate_pdf_preview_images(attachment, data)
       ActiveStorage::Attachment.where(name: ATTACHMENT_NAME, record: attachment).destroy_all
-      number_of_pages = HexaPDF::Document.new(io: StringIO.new(data)).pages.size - 1
+      number_of_pages = HexaPDF::Document.new(io: StringIO.new(data)).pages.size
 
-      (0..number_of_pages).each do |page_number|
+      (attachment.metadata['pdf'] ||= {})[:number_of_pages] = number_of_pages
+
+      attachment.save!
+
+      (0..[number_of_pages - 1, MAX_NUMBER_OF_PAGES_PROCESSED].min).each do |page_number|
         page = Vips::Image.new_from_buffer(data, '', dpi: DPI, page: page_number)
         page = page.resize(MAX_WIDTH / page.width.to_f)
 
         io = StringIO.new(page.write_to_buffer(FORMAT, Q: Q, interlace: true))
 
+        ApplicationRecord.no_touching do
+          ActiveStorage::Attachment.create!(
+            blob: ActiveStorage::Blob.create_and_upload!(
+              io:, filename: "#{page_number}#{FORMAT}",
+              metadata: { analyzed: true, identified: true, width: page.width, height: page.height }
+            ),
+            name: ATTACHMENT_NAME,
+            record: attachment
+          )
+        end
+      end
+    end
+
+    def generate_pdf_preview_from_file(attachment, file_path, page_number)
+      page = Vips::Image.new_from_file(file_path, dpi: DPI, page: page_number)
+      page = page.resize(MAX_WIDTH / page.width.to_f)
+
+      io = StringIO.new(page.write_to_buffer(FORMAT, Q: Q, interlace: true))
+
+      ApplicationRecord.no_touching do
         ActiveStorage::Attachment.create!(
           blob: ActiveStorage::Blob.create_and_upload!(
             io:, filename: "#{page_number}#{FORMAT}",
@@ -59,6 +89,8 @@ module Templates
           record: attachment
         )
       end
+
+      io
     end
   end
 end