servicenow change the list of acceptable file types

2025

3 min read 26-03-2025

servicenow change the list of acceptable file types

ServiceNow's robust platform allows for flexible file management, but sometimes you need to fine-tune which file types are permitted for uploads. This article guides you through modifying the acceptable file types in ServiceNow, ensuring only approved files are uploaded into your system. We'll cover several approaches, from simple configuration changes to more advanced techniques leveraging scripting.

Understanding File Type Restrictions in ServiceNow

Before diving into the changes, it's crucial to understand where ServiceNow controls file type restrictions. These settings vary depending on the specific context:

Attachment Fields: Many ServiceNow tables include attachment fields (e.g., attachment, sys_attachment). These fields inherently have limitations on file types, often controlled by the system's default settings.
Custom Applications: Applications you or your organization built might have custom restrictions implemented via scripts or client-side validation.
Upload Sets: For more granular control, you might be using upload sets. These allow for stricter file type validation.

Method 1: Modifying Default File Type Restrictions (Simplest Approach)

While not always directly configurable through a simple interface, ServiceNow's default file type restrictions can sometimes be influenced indirectly. This approach isn't guaranteed to work in all cases, as it depends on your ServiceNow instance's configuration. You might need to contact your ServiceNow administrator to help make the following changes:

Identify the Relevant Table: Determine the table containing the attachment field you want to modify. This is often a core table, such as incident, problem, change_request, etc.
Explore Table Configuration: Look for any settings within the table's configuration that might relate to file uploads or allowed MIME types. This is typically found in the table's properties or within the field definitions.
Contact Support: If direct configuration isn't possible, reach out to ServiceNow support or your administrator. They may have access to system-level settings that control default file type acceptance.

Method 2: Implementing Client-Side Validation (JavaScript)

For more control, client-side validation using JavaScript offers a practical solution. This method checks the file type before the upload even begins, preventing unwanted files from being submitted. This requires familiarity with ServiceNow's client-side scripting capabilities.

This example utilizes a simple JavaScript function within a UI Action or a UI Page:

function validateFileType(file) {
  var allowedTypes = ["application/pdf", "image/jpeg", "image/png"]; // Add your desired types
  var fileType = file.type;

  if (allowedTypes.indexOf(fileType) === -1) {
    alert("Invalid file type. Please upload a PDF, JPEG, or PNG file.");
    return false;
  }
  return true;
}

Remember to integrate this function into your UI Action or UI Page's onSubmit client script to execute before the upload proceeds. This ensures the file type is checked before transmission to the server.

Method 3: Using a Script Include (Server-Side Validation)

Client-side validation is excellent for user experience, but server-side validation provides additional security. A script include provides a central location to manage allowed file types. This script runs on the ServiceNow server and enforces the rules before the file is saved.

var FileValidation = Class.create();
FileValidation.prototype = {
    initialize: function() {
    },
    validateFileType: function(fileName) {
        var allowedTypes = ["pdf", "jpg", "jpeg", "png"]; // Add desired extensions
        var fileExtension = fileName.substring(fileName.lastIndexOf('.') + 1).toLowerCase();
        return allowedTypes.indexOf(fileExtension) > -1;
    },
    type: 'FileValidation'
};

This script include's validateFileType function can be called from a Business Rule before an attachment is inserted or updated. The Business Rule would check the return value and prevent the insertion if the file type is invalid.

Method 4: Leveraging Upload Sets (Advanced Control)

Upload sets provide the most comprehensive approach, especially for complex scenarios. They allow detailed control over file types, sizes, and other upload parameters.

Create a New Upload Set: Navigate to the Upload Set table (sys_upload_set) and create a new record.
Configure Allowed File Types: Within the upload set's properties, specify the permitted file types (using MIME types or extensions).
Associate with Form: Link the newly created upload set to the relevant form or table. This ensures that the upload set's restrictions apply.

Conclusion: Choosing the Right Approach for Changing Acceptable File Types

The best method for changing acceptable file types in ServiceNow depends on your technical skills and the level of control required. Simple adjustments to default settings might suffice in some instances, while client-side, server-side validation, or upload sets offer progressively more powerful and flexible solutions. Remember to thoroughly test any changes to avoid unintended consequences. Always back up your instance before making significant modifications.