add pdf generation

app/controllers/esign_settings_controller.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+class EsignSettingsController < ApplicationController
+  before_action :load_encrypted_config
+
+  def create
+    attachment = ActiveStorage::Attachment.find_by!(uuid: params[:attachment_uuid])
+
+    pdf = HexaPDF::Document.new(io: StringIO.new(attachment.download))
+
+    pdf.signatures
+  end
+
+  private
+
+  def load_encrypted_config
+    @encrypted_config =
+      EncryptedConfig.find_or_initialize_by(account: current_account, key: EncryptedConfig::ESIGN_CERTS_KEY)
+  end
+
+  def storage_configs
+    params.require(:encrypted_config).permit(value: {}).tap do |e|
+      e[:value].compact_blank!
+    end
+  end
+end