Restrict file extensions for File Attachment field type

[Eduard T]

Hello,

I have been looking for an attribute that could restrict the file extensions for the File Attachment field type on a table level, not on a global level (in order to only allow PDFs to be attached) but couldn't find any. Are you aware of any solution for this? Thank you!

[Musab Rasheed]

Hello,

allowed_extensionsSpecifies a list of allowed file types. For example, allowed_extensions=txt;pdf.

Applicable variables: Attachment.

https://docs.servicenow.com/bundle/rome-servicenow-platform/page/product/service-catalog-management/...

https://www.servicenow.com/community/it-service-management-forum/i-have-created-a-catalog-item-in-wh...

https://www.servicenow.com/community/it-service-management-forum/need-to-restrict-the-attachment-var...

[Eduard T]

Hi @Musab Rasheed ,

I am talking about the File Attachment field type, not about the Attachment catalog variable. The allowed_extensions attribute doesn't seem to work on the File Attachment field

[tienminhngu]

Hello,

Have you find the solution for your issue ? 

[Anuj kumar sin2]

To restrict file extensions for attachments, you'll need to approach the problem from a server-side perspective using a Business Rule or a Script Include that runs when an attachment is added to the sys_attachment table.

Here’s how you can do it using a Business Rule on the sys_attachment table:

Steps to Restrict File Extensions for Attachments

1. Create a Business Rule:

   • Navigate to System Definition > Business Rules.
   • Click on New to create a new Business Rule.

2. Configure the Business Rule:

   • Name: Give it a meaningful name (e.g., Restrict File Extensions).
   • Table: Select sys_attachment as the table.
   • When: Select before for when you want the rule to run.
   • Insert: Check the Insert checkbox, as we want the rule to run when a new attachment is inserted.

3. Add the Script to the Business Rule:

   (function executeRule(current, previous /*null when async*/) {
   var validExtensions = ['pdf', 'jpg', 'png']; // List of allowed extensions
   var fileName = current.file_name.toLowerCase();
   var fileExtension = fileName.split('.').pop(); // Get the file extension

   // Check if the file extension is not in the list of allowed extensions
   if (validExtensions.indexOf(fileExtension) === -1) {
   gs.addErrorMessage('Invalid file type. Only ' + validExtensions.join(', ') + ' are allowed.');
   
   // Abort the attachment insertion
   current.setAbortAction(true);
   }
   })(current, previous);