Preventing Duplicate Attachments in Bi-Directional Sync (sc_task to rm_story)

[mustakim1119]

Hi Community, 

I am facing an issue with duplicating attachments while syncing files from Catalog Task (sc_task) to Story (rm_story). 

Scenario: 

• Our integration is bi-directional: ServiceNow to Azure DevOps and vice-versa.
• The flow is: User adds an attachment to sc_task→itsyncs to the linked rm_story via a Business Rule→from the Story, it flows to Azure via a work item integration.
• The Issue: When a second attachment is added to the Task, the system is duplicating the first attachment on the Story level.
• I have tried using GlideSysAttachment.copy(), but it performs a bulk copy of all attachments every time, causing the duplicates. I also attempted writeContentStream, but I am struggling to get it to execute correctly.
  
  
  
  Current Logic (After Insert BR on sys_attachment):
  when to run condition: table name is sc_task.

  (function executeRule(current, previous) {

      var taskGR = new GlideRecord('sc_task');

      if (taskGR.get(current.table_sys_id) && taskGR.agile_story) {

          var storyID = taskGR.getValue('agile_story');

          var sa = new GlideSysAttachment();

          // Copy EVERYTHING

          // Immediately find and delete duplicates on the Story

          var dup = new GlideRecord('sys_attachment');

          dup.addQuery('table_name', 'rm_story');

          dup.addQuery('table_sys_id', storyID);

          dup.addQuery('file_name', current.file_name);

          dup.addQuery('size_bytes', current.size_bytes);

          dup.orderByDesc('sys_created_on');

          dup.setLimit(1);

          dup.query();

          sa.copy('sc_task', taskGR.sys_id, 'rm_story', storyID);

          // If more than 1 exists, delete the older one

          if (dup.getCount() > 1) {

              dup.next(); // Keep the newest one

              while (dup.next()) {

                  dup.deleteRecord();

                  gs.log("ATTACHMENT_DEBUG: Triggered by " + gs.getSession().getInteractiveStack());

                  // if (!check.hasNext()) {

                  // // 3. COPY ONLY THIS FILE

                  // var sa = new GlideSysAttachment();

                  // // This method creates a single copy of the current record only

                  // sa.writeContentStream(

                  //     'rm_story',

                  //     storyID,

                  //     current.file_name,

                  //     current.content_type,

                  //     sa.getContentStream(current.sys_id)

                  // );

                  // }

              }

          }

      }

  })(current, previous);

  
  
  
  What I need:
  1. A way to copy only the current attachment being added to the sc_task over to the rm_story.
  2. A check to ensure that if the attachment is coming from the Azure integration, it doesn't loop back (avoiding infinite loops).
     
     
  Has anyone successfully implemented a "single-file sync" between these tables that handles bi-directional logic without creating duplicates?
  
  
  Any help or code snippets using writeContentStream or copyAttachment for a single record would be greatly appreciated!
  
  
  Regards,
  Mustakim