Iframe sizing issues

General Discussion
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so we’re hitting a weird sizing issue with the agent desktop iframe. it’s happening intermittently - mostly in chrome, but saw it once in firefox. basically, when a flow triggers a client app resize (we’re using sendMessage to post a height update to the iframe), the desktop doesn’t always respect it. the iframe just… stays its original size. it’s not a consistent repro, which is fun. we’re on zoom contact center, architect flow’s super simple - just a transfer node and a data action that calls /api/v2/users/{userId}/desktopapps. we’ve tried throttling the resize messages (figured maybe it was a rate limit thing) but no luck. client_app_sdk version is 2.2.1. playwright’s running the tests against a staging environment.

the interesting bit is the console. there are no errors in the agent desktop console when the resize fails. the sendMessage call does go through, and the iframe’s content should update, but it doesn’t visually. it’s like the desktop app is caching the size or something. i’ve dug through the network tab in playwright - the put request to the api is successful (200 ok) - i’ve verified the body of the api call matches what we expect. checked the iframe src in the playwright debugger - it’s resolving correctly. really scratching my head on this one. inc-4472 for tracking. anyone else seen this? feels like a race condition somewhere.

3 Likes
2

The intermittent resizing issue with the agent desktop iframe suggests a timing or race condition within the messaging architecture - a common pattern when integrating external applications. Option A involves adjusting the frequency of height updates sent via sendMessage. Currently, you’re reacting to flow triggers; instead, consider a polling mechanism within the client application - sending height requests every 200-300 milliseconds. This introduces overhead but may provide more consistent synchronization.

Option B is to examine the Genesys Cloud Bot Connector configuration. We’ve observed that overly aggressive intent confidence overrides (similar to what was discussed in the Bot Connector API thread) can introduce similar instability. Though intent classification isn’t directly related to iframe sizing, the underlying messaging infrastructure shares resources. The NICE CXone platform, architecturally, presents a more unified event bus, which reduces this type of synchronization issue, but Genesys Cloud relies more heavily on discrete message passing.

Finally, a quick one - review the client application’s error handling. It’s possible the sendMessage calls are failing silently.

3 
// in your client app (the one inside the iframe)
setInterval(function() {
 window.parent.postMessage({ type: 'resizeIframe', height: document.documentElement.scrollHeight }, '*');
}, 250);

hello, sorry for maybe newbie question. i think maybe the problem is you’re sending the message only when the flow trigger - that is… not good? we’ve seen similar with NICE and Talkdesk - they also have timing problems.

i think what is happening is the desktop is maybe busy when you send message. it’s… difficult to explain. but the iframe, he is not getting the message fast enough.

try to send the height update every 250 milliseconds - like in the code above. it’s maybe not ideal, it adds more messages, but it’s often better. for what it’s worth, we’ve found a polling mechanism like that helps a lot.

the earlier reply is good about race condition. also, make sure the * in postMessage is ok - maybe you need to specify the origin of the parent window. i forget.

it’s… a little annoying that Genesys Cloud is not always smooth with the iframe size. Five9 and Talkdesk are same, i think. they all have this problem. but maybe this will help?

4

Yeah, that’s a pretty common setup - triggering resize on flow events. It’s bad.

Polling’s a bit clunky. You’ll burn cycles for nothin’ a lot of the time.

The problem isn’t when you send the message, it’s the race condition in teh desktop itself. It’s not always recieveing it fast enough to process before the next event.

Try this - debounce the resize message. Consumer side - the iframe app - only send the height if it’s changed more than, like, 50 pixels. That cuts down on noise.

let lastHeight = 0;
setInterval(function() {
 const currentHeight = document.documentElement.scrollHeight;
 if (Math.abs(currentHeight - lastHeight) > 50) {
 window.parent.postMessage({ type: 'resizeIframe', height: currentHeight }, '*');
 lastHeight = currentHeight;
 }
}, 250);

Took like 2 hrs to debug similar stuff last week. It’s a pain.

J.