How to Force a Cache Update for UI Scripts - Developer Community - Article - ServiceNow Community


Tue Dec 22 2020 18:09:41 GMT+0000 (Coordinated Universal Time)

Saved by #servicenow #ui #script #uiscript

Fear Not; There is a Better Workaround
...and I do mean workaround. This is by no means to be considered a fix. The secret is in the browser cookies. We know that many plugins contain UI Scripts. These applications are updated from time to time (including the UI Scripts) and that works fine. What's the difference? Activating a plugin triggers a forced cache update for the users' browsers. The difference is that updating a UI Script doesn't trigger this. Not even a triggers it. It simply forces the server to update cache. Installing/updating plugins seems to be the sole trigger that forces the browser to ask the server for updated cache for UI Scripts.

So how do you force this cache update?
The check for building new cache in this instance is controlled by a cookie on the client browser that ServiceNow creates. The cookie is controlled by a property in ServiceNow called glide.lastupdate. To force this update to happen, all you have to do is set that property to a newer dateTime than it currently is (e.g. the current timestamp). You can do this manually, but that can also be a form of kicking the can down the road. You will be back here soon. At Walmart, we wrote a Business Rule to update this whenever a ui_script is updated:

(function executeRule(current, previous /*null when async*/) {
	var gdt = new Date();
	var gdtString = gdt.toString().replace(/ /g,'_').replace(/:/g,'_');
	var timeZone = gdtString.replace(/.*[(](.*)[)].*/,'$1');
	var dateFinal = gdtString.slice(0,25) + timeZone;
	gs.addInfoMessage('System Property glide.lastplugin updated. ' + 
					  'Please be sure to push this updated property with the rest of your code. ' +
					  'This will ensure that the JavaScript cache is updated on the client browser.');
	gs.setProperty('glide.lastplugin', dateFinal);
})(current, previous);
I have attached an export of this business rule for any who are interested. The info message reminds developers to ensure this updated property is included in their update set, since business rules are not triggered on update commit.