info-beamer

Debug web pages in fullscreen-browser package

Hello everyone! I have run into an issue with the fullscreen-browser package and would appreciate some help.

I have a webpage that I would like to display on the info-beamer device. However, the webpage does not load properly on the raspberry pi. The page renders fine on my laptop using chromium, but on the pi the page only loads partially, which I assume is due to failing XHR requests. I have no way of confirming this, though.

I would very much like to access the browser console to see why exactly the page does not render, however, I don’t know how to do that. I’d have to access it on the pi itself, since I cannot reproduce the issue on my own laptop. I’ve tried connecting a keyboard to the pi (which doesn’t seem to get recognized) and I tried accessing it via SSH (but couldn’t figure out how to access Chromium logs that way).

The page in question is https://viscon-screens.svis.ethz.ch/talks - on the pi, the schedule does not load. I think this issue could also be related to browser versions, but I have no clue which version of chromium the fullscreen-browser package uses.

Any help would be greatly appreciated.
Thank you in advance,
Aline

If you access the device with SSH, you can run logread -f to follow the in-memory log output generated (See also debugging on a device). I created a setup, specified your Url and found the following output:

Oct  9 14:46:02 info-beamer-143594677 user.notice service.root: [26:26:1009/164602.793014:INFO:CONSOLE(39)] "jQuery.Deferred exception: n.schedule.conference.days.flatMap is not a function", source: https://viscon-screens.svis.ethz.ch/js/chunk-vendors.06116acd.js (39)
Oct  9 14:46:02 info-beamer-143594677 user.notice service.root: [control] <<< {u'params': {u'timestamp': 1570632362791.88, u'args': [{u'type': u'string', u'value': u'jQuery.Deferred exception: n.schedule.conference.days.flatMap is not a function'}, {u'type': u'string', u'value': u'Typ
Oct  9 14:46:02 info-beamer-143594677 user.notice service.root:     at l (https://viscon-screens.svis.ethz.ch/js/chunk-vendors.06116acd.js:39:25870)'}, {u'type': u'undefined'}], u'type': u'warning', u'executionContextId': 2, u'stackTrace': {u'callFrames': [{u'url': u'https://viscon-sc

It seems array.flatMap isn’t available in the browser version used. It’ll be updated soon, so in the future it should work out of the box. Meanwhile you should be able to use a polyfill: https://github.com/jonathantneal/array-flat-polyfill

Thank you very much for the quick reply! That’s very great to know!

I actually checked logread -f but it seems the javascript error was already off the screen by the time and I falsely assumed it wouldn’t show up there.

But now I’m confident we can fix the issue ourselves by adapting the webpage.

Again, thanks a lot!

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