Automatic image refresh does not work

[sidamos]

I have an image widget with an openHAB String item which contains a snapshot url for my Nest camera and I have set auto refresh to 60 seconds.

Instead of refreshing the image, I get this in the browser console:
vendor.js:119 TypeError: Cannot read property 'indexOf' of undefined
at image.widget.js:70
at n (vendor.js:108)
at m.$eval (vendor.js:147)
at m.$digest (vendor.js:144)
at m.$apply (vendor.js:147)
at vendor.js:109

When I enable No Cachebusting, then I don't get an error in the browser console, but the image goes black after 60 seconds.

Using openHAB 2.4.0. Tested on newest Chrome version on Linux and Android.

[sidamos]

I did further testing and auto refresh does work if I use the Nest URL as a static URL instead of from an openHAB String Item.

For an example on how the image URL looks like (I deleted some chars here and there, so that it does not really work with my camera):

https://www.dropcam.com/api/wwn.get_snapshot/CjYtbXFPZXFVDaXp6eWJoOENHcEJKWEhqWE5Nb2Q2ZlBsTlZo4Z2x6YjVsNWhYcamcSFjdCejZHSHFtdXV4ZzlKUmlweUZVY1EaNm1SSlFPWjlVMHNxNnoweW5GMkhCLWsyOGE5NWdxRTWI5ZF83YnI2MTRLX25rQ2FCNERlQQ?auth=462ZAS4JeGb7hg6yK3siAVwiiz-xTomCKQKEUnVJ5BLB5ANy_a-7fcwF3ysEVMOyjGDY0tgJR_rrtQSvTl_P7JYVnl4QYzJRpttyqKAOAf41nyB7DjZ9_RW62fNFJ1Bh_VTz4qOBrEEABfNdtdmAkTE1sRq_F2hE0TZB9l7M0C80dY0mf3W3upZfXaM-3ns

[ghys]

Looks like vm.original_url could indeed be undefined.

org.openhab.ui.habpanel/web/app/widgets/image/image.widget.js

Line 70 in 7fbdf02

vm.url = (vm.original_url.indexOf('?') === -1) ?

Since it's only defined here - only for static urls:

org.openhab.ui.habpanel/web/app/widgets/image/image.widget.js

Lines 58 to 60 in 7fbdf02

	if (!this.widget.image_source || this.widget.image_source === 'static') {
	vm.original_url = vm.url = this.widget.url;
	}

This was introduced in #143.
I think the rationale at the time was that if you're specifying a String item, you're responsible for autoupdating it via rules instead of relying on the widget's autoupdate. Nonetheless, it's still a bug.

[sidamos]

At the moment, I am using a time triggered rule as a workaround, but it is very hacky:

rule "Nest Snapshot Refresh"
when
Time cron "0 0/5 * * * ?" // every 5 minutes
then
var orig = FrontDoorCameraNestHello_Camera_SnapshotURL.state.toString
FrontDoorCameraNestHello_Camera_SnapshotURL.sendCommand("/static/black.jpg")
Thread::sleep(500)
FrontDoorCameraNestHello_Camera_SnapshotURL.sendCommand(orig)
end

It is necessary to really change the URL and the sleep is also necessary, otherwise it won't update.

[LuckyMallari]

I will check if we can add input validation on the widget configuration when I get on a PC.