RefFieldFetcher — One Script Include to Replace All Your GlideAjax Endpoints (Free Update Set)

[dhravesh]

Hi everyone,

I built RefFieldFetcher to solve a problem I've seen on every ServiceNow project — developers creating dozens of nearly-identical Script Includes just to do async reference lookups via GlideAjax.

THE PROBLEM:
• g_form.getReference() and getXMLWait() are synchronous — they freeze the form
• Teams create a new Script Include for every GlideAjax use case
• 50 developers × 3 years = unmaintainable Script Include sprawl with inconsistent security

THE SOLUTION:
RefFieldFetcher is a single, client-callable Script Include that handles all async reference field lookups. Pass it a table, sys_id(s), and fields — it returns structured JSON.

FEATURES:
• Dot-walk support — fetch caller_id.department.name in one call
• Three return modes — value, display, or both
• Encoded query support — not just sys_id lookups
• 7-layer security — table allowlist, field denylist, ACL enforcement, dot-depth limits, encrypted type blocking, encoded query validation, admin-only ACL bypass
• 9 system properties — configure everything without touching code
• User-scoped caching with configurable TTL
• Server-side direct call via getFieldsDirect()

BEFORE (synchronous):
var rec = g_form.getReference('caller_id'); // FREEZES THE FORM
g_form.setValue('location', rec.location);

AFTER (async with RefFieldFetcher):
var ga = new GlideAjax('RefFieldFetcher');
ga.addParam('sysparm_name', 'getFields');
ga.addParam('sysparm_table', 'sys_user');
ga.addParam('sysparm_sys_ids', newValue);
ga.addParam('sysparm_fields', 'name,email,location.name');
ga.addParam('sysparm_mode', 'display');
ga.getXMLAnswer(function(answer) {
var data = JSON.parse(answer);
if (data.rows && data.rows.length) {
g_form.setValue('location', data.rows[0]['location.name']);
}
});

Same result. Zero form freeze. Zero new Script Includes.

DOWNLOAD & FULL DOCUMENTATION:
GitHub: https://github.com/dhravesh07/servicenow-solutions/tree/main/RefFieldFetcher

The Update Set XML contains 1 Script Include + 9 System Properties. Import via Retrieved Update Sets > Import Update Set from XML.

Tested on Washington DC, Vancouver, and Utah. Global scope, no dependencies.

Would love to hear feedback or if anyone has similar patterns they've solved differently!