VNC clipboard Unicode support

[Nyla Khalil <ny...@gmail.com>]

I have TigerVNC Server v1.11.90 Beta
(https://github.com/TigerVNC/tigervnc/releases/tag/v1.11.90) and
Guacamole 1.3.0 running on my Linux system. I need to copy paste
non-Latin characters.

TigerVNC client and Guacamole SSH connection handle Unicode characters
correctly. If I use Guacamole VNC connection with Clipboard Encoding
set to UTF-8, copy pasting Unicode characters results in
transformation issues (possibly UTF-8 to ISO-8859-1). I think this is
due to Guacamole's LibVNC library usage
(https://issues.apache.org/jira/browse/GUACAMOLE-1043). Is there a way
to fix this?

LibVNC/libvncserver 1.0.0 release will add support for UTF-8 clipboard
(https://github.com/LibVNC/libvncserver/pull/468). If I build
Guacamole with the LibVNC UTF-8 changes, will it automagically work or
is there some integration needed on the Guacamole side?

Guacamole Docs:
"As most VNC servers will not accept data in any other format,
Guacamole will translate between UTF-8 and ISO 8859-1 when exchanging
clipboard data with the VNC server, but this behavior can be
overridden with the clipboard-encoding parameter."

Examples:
"£" pasted in TigerVNC client correctly pastes as "£"
"£" pasted in Guacamole VNC connection via sidebar menu incorrectly
pastes as "£"
"£" pasted in Guacamole SSH connection via sidebar menu correctly pastes as "£"

Guacd Log shows UTF-8 Usage:
guacd[6252]: DEBUG: Client is using protocol version "VERSION_1_3_0"
guacd[6252]: INFO: Using non-standard VNC clipboard encoding: 'UTF-8'.

TigerVNC log shows UTF-8 Usage:
Selection:   Remote clipboard announced, grabbing local ownership
Selection:   Grabbed PRIMARY selection
Selection:   Grabbed CLIPBOARD selection
Selection:   Selection request for CLIPBOARD (type TARGETS)
Selection:   Selection request for CLIPBOARD (type TARGETS)
Selection:   Selection request for CLIPBOARD (type UTF8_STRING)
Selection:   Requesting clipboard data from client
Selection:   Got remote clipboard data, sending to X11 clients
Selection:   Sending data for selection request for CLIPBOARD (type UTF8_STRING)
Selection:   Sending data for selection request for CLIPBOARD (type UTF8_STRING)

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Re: VNC clipboard Unicode support

[Nick Couchman <vn...@apache.org>]

On Mon, Oct 25, 2021 at 10:02 PM Nyla Khalil <ny...@gmail.com> wrote:

> I have TigerVNC Server v1.11.90 Beta
> (https://github.com/TigerVNC/tigervnc/releases/tag/v1.11.90) and
> Guacamole 1.3.0 running on my Linux system. I need to copy paste
> non-Latin characters.
>
> TigerVNC client and Guacamole SSH connection handle Unicode characters
> correctly. If I use Guacamole VNC connection with Clipboard Encoding
> set to UTF-8, copy pasting Unicode characters results in
> transformation issues (possibly UTF-8 to ISO-8859-1). I think this is
> due to Guacamole's LibVNC library usage
> (https://issues.apache.org/jira/browse/GUACAMOLE-1043). Is there a way
> to fix this?
>
>
Not without either a) support from LibVNC, or b) switching to a client
library that does support it.


> LibVNC/libvncserver 1.0.0 release will add support for UTF-8 clipboard
> (https://github.com/LibVNC/libvncserver/pull/468). If I build
> Guacamole with the LibVNC UTF-8 changes, will it automagically work or
> is there some integration needed on the Guacamole side?
>
>
Hard to say - there may be some changes that have to be made in the
Guacamole code keep it from trying to translate if the underlying library
supports UTF-8, but I haven't looked at the code, so I'm not sure about
that.


> Guacamole Docs:
> "As most VNC servers will not accept data in any other format,
> Guacamole will translate between UTF-8 and ISO 8859-1 when exchanging
> clipboard data with the VNC server, but this behavior can be
> overridden with the clipboard-encoding parameter."
>
> Examples:
> "£" pasted in TigerVNC client correctly pastes as "£"
> "£" pasted in Guacamole VNC connection via sidebar menu incorrectly
> pastes as "£"
> "£" pasted in Guacamole SSH connection via sidebar menu correctly pastes
> as "£"
>
>
Seems like there may be some changes that need to be made.

-Nick