Unsupported tight encoding with noVNC 1.0.0

[KeithMnemonic]

When using noVNC 1.0.0 to connect to the VNC server of an instance running on ESXi 6.7, the following error occurs.

Failed while connected: Unsupported encoding (encoding: -260)

Using RealVNC, I can directly connect to the VNC server provided by ESX to that vm so I know the ESX firewall and such is correct.

I can reproduce this by simply running this on a SLES 12 SP3 host

sudo ./websockify.py -v --web= HOSTIP:PORT ESXIP:VNCPORT

Using Chrome developer tools, I can see it connect and it will actually register mouse clicks. The instant you type any character in the vnc screeen though it fails with

Sending keysym (down): 100
keyboard.js:42 onkeyevent up, keysym: 100 , code: KeyD
rfb.js:376 Sending keysym (up): 100
rfb.js:685 Failed while connected: Unsupported encoding (encoding: -260)
_fail @ rfb.js:685
_framebufferUpdate @ rfb.js:1517
_normal_msg @ rfb.js:1422
_handle_message @ rfb.js:725
_recv_message @ websock.js:304
rfb.js:635 New state 'disconnecting', was 'connected'.
rfb.js:427 >> RFB.disconnect
keyboard.js:276 >> Keyboard.allKeysUp
keyboard.js:281 << Keyboard.allKeysUp
websock.js:239 Closing WebSocket connection

Expected behavior
The console should connect without any issues.

Screenshots
JS stack trace illustrates the issue.

Client (please complete the following information):

• OS: Windows 10
• Browser: Chrome
• Browser version: Version 75.0.3770.142 (Official Build) (64-bit)

Server (please complete the following information):

• noVNC version: 1.0.0
• VNC server: Whatever ESX 6.7 uses, seems like some form of Tight
• WebSocket proxy: websockify 0.8.0.
• HOST OS: SLES 12 SP3

I resolved the issue by applying three changes to the encodings.js file

Add:

noVNC/core/encodings.js

Line 15 in 9fe2fd0

encodingTightPNG: -260,

Add:

noVNC/core/encodings.js

Line 15 in 9fe2fd0

encodingTightPNG: -260,

Remove:

https://github.com/novnc/noVNC/blob/v1.0.0/core/encodings.js#L22

Once I applied these changes, I could successfully access the VNC console

[samhed]

How come you are using noVNC 1.0.0? This was fixed in 1.1.0

[KeithMnemonic]

Currently the Rocky release of OpenStack requires 1.0.0. There is a patch in process to change this to 1.1.0. https://review.opendev.org/#/c/674916/ This is related to #1220

[samhed]

Well OK, it's fixed as far as we are concerned anyway.

[KeithMnemonic]

How is it fixed? There are other version of OpenStack that are bound to 1.1.0 that can not be patched. Or are you referring to the fact I included a workaround?

[samhed]

I wasn't referring to your workaround. Why would a OpenStack version that uses noVNC 1.1.0 need to be patched?

Apologies if we are misunderstanding each other here, could you explain what you think we should do? Keep these things in mind:

• This is fixed in a stable release of noVNC (1.1.0)
• We can't control what version of noVNC other projects use

[KeithMnemonic]

Only the two most recent version support 1.1.0. All previous only work with 1.0.0. We have a patch to allow Rocky (3rd most recent) to work with 1.1.0 but there are other versions that wont get a patch to allow them to use 1.1.0

[samhed]

Again - what would you wish that we did?

[KeithMnemonic]

I was not sure if you accepted patches to previous versions? If not it can remain closed and if anyone else runs into the issue they can find the workaround. If you accept patches, can I do a PR on 1.0.0 to like 1.0.1 or something?

[CendioOssman]

I'm afraid we don't have the resources to maintain bug fix branches, so we really need to have people updating to the latest version to get all fixes.

[samhed]

Ok, sorry for the misunderstanding @KeithMnemonic

[KeithMnemonic]

no problem at least it is documented now. thanks again