Webcam feed breaks if snapshot URL returns intermittent 404

[antifuchs]

Bug Report

Description

I run mobileraker with a Snapmaker U1, which has a mildly flaky webcam endpoint: You point it at the snapshot URL and it'll update the picture there on an ongoing basis. When streaming from that you get about 10 FPS or so, just enough to follow along. Unfortunately, their image update process has a race condition where sometimes the snapshot.jpg goes away and the web server returns a 404 for a very brief moment. When that happens, MobileRaker displays the attached screenshot and you have to hit "Reconnect".

Steps to Reproduce

1. Add a U1 printer and point the webcam snapshot and stream links at /server/files/camera/monitor.jpg
2. Open the webcam feed full-screen and select the second camera (apparently the first one is only the snapshot)
3. Wait a few seconds
4. See the error.

Expected Behavior

If it received an image once, I'd expect MobileRaker to automatically retry fetching the stream URL; a choppy feed is much better than no feed at all.

Screenshots

Version Information

• Device-OS (Android/iOS): iOS
• Mobileraker: 2.9.6-687
• Klipper: (not sure how to retrieve. Webface shows fluidd: v1.36.2-ac48b4dc)
• Moonraker: [version]

Debug Logs

mobileraker_2026-03-17T09-28-59.log

Additional Context

I'm not sure why the webcam full-screen view displays two available cameras, even though I configured only one (and why the default one shows a static image with an FPS of 0); only the second camera delivers a non-static image stream with FPS >0, and that one exhibits the issue.

Checklist

To help us diagnose the issue, please ensure you've completed the following steps:

• Provided a clear bug description.
• Listed detailed steps to reproduce the issue.
• Described the expected behavior.
• Included the Mobileraker version you are using.
• Attached Mobileraker's debug log files.
• Specified the version numbers of Klipper and Moonraker if applicable.

[Clon1998]

I also have an U1, but thought they disabled access to the webcam feed unless you run the jailbreak OS?
Did they finally open it?

[antifuchs]

They didn't open it up, but you can run an authenticated websocket client from another machine that keeps the camera turned on: I used this guide (stock firmware + external keepalive) to keep it online (plus keeping the printer on a remote-controllable outlet so I don't have a permanently accessible webcam on my network).