TJ Fragment: Sharing Desktop Apps Via Jupyter-Server-Proxy Et Al.

It’s been some time since I last had a play with remote desktops, so here’s a placeholder / round up of a couple of related Jupyter server proxy extensions that seem to fit the bill.

For those at the back who aren’t keeping up, jupyter-server-proxy applications are incredibly useful: they extent the Jupyter server to proxy other services running in the same environment. So if you have a Jupyter server running on example.url/nbserver/, and another application that publishes a web UI in the same environment, you can publish that application, using jupyter-server-proxy, via example.url/myapplication. As an example, for out TM351 Data Management and Analysis course, we proxy OpenRefine using jupyter-server-proxy (example [still missing docs].).

Applications that are published using a jupyter-server-proxy wrapper are typically applications that publish an HTML UI. So what do you do if the application you want to share is a desktop application? One way is to to share the desktop via a browser (HTML) interface. Two popular ways of doing this are:

  • novnc: an “open source VNC client – it’s is both a VNC client JavaScript library as well as an application built on top of that library”;
  • xpra: “an open-source multi-platform persistent remote display server and client for forwarding applications and desktop screens”.

Both of these applications allow you to share (Linux) desktop applications via a web browser, and both of them are available as jupyter-server-proxy extensions (subject to the correct operating system packages also being installed).

As far as novnc goes, jupyterhub/jupyter-remote-desktop-proxy will “run a Linux desktop on the Jupyter single-user server, and proxy it to your browser using VNC via Jupyter”. A TightVNC server is bundled with the application as a fallback if no other VNC server is available. One popular application used wrapped by several people using jupyter-remote-desktop-proxy is QGIS; for example, giswqs/jupyter-qgis. I used it to demonstrate how we could make a legacy Windows desktop application available via a browser by running using Wine on a Linux desktop and then sharing it via the jupyter-remote-desktop-proxy.

For xpra, the not very active (but maybe it’s stable enough?!) FZJ-JSC/jupyter-xprahtml5-proxy seems to allow you to “integrate Xpra in your Jupyter environment for an fast, feature-rich and easy to use remote desktop in the browser”. However, no MyBinder demo is provided and I haven’t had a chance yet to give this a go. (I have tried XPRA in other contexts, though, such as here: Running Legacy Windows Desktop Applications Under Wine Directly in the Browser Via XPRA Containers.)

Another way of sharing desktops is to use the Microsoft Remote Desktop Protocol (aka RDP). Again, I’ve used that in various demos (eg This is What I Keep Trying to Say…) but not via a jupyter-server-proxy. I’m not sure if there is a jupyter-server-proxy example out there for publishing a proxied RDP port?

Just in passing, I also note this recipe for a Docker compose configuration that uses a bespoke container to act as a desktop sharing bridge: Viewing Dockerised Desktops via an X11 Bridge, novnc and RDP, Sort of…. I’m not sure how that might fit into in Jupyter set up? Could a Jupyter server container be composed with a bridge container, and then proxy the bridge services?

Finally, another way to share stuff is to to use WebRTC. The maartenbreddels/ipywebrtc extension can “expose the WebRTC and MediaStream API in a Jupyter notebook/JupyterLab environment” allowing you to create a MediaStream out of an ipywidget, a video/image/audio file, or a webcam and use it as the bases for a movie, image snapshot or audio recording. I keep thinking this might be really useful for recording screencast scenes or other teaching related assets, but I haven’t fully grocked the full use of it. (Something like Jupyter Graffiti also falls into this class, which can be used to record a “tour” or walkthrough of a notebook that can also be interrupted by live interaction or the user going off-piste. The jupyterlab-contrib/jupyterlab-tour extension also provides an example of a traditional UI tour for JupyterLab, although I’m not sure how easy it is to script/create your own tours. Such a thing might be useful for guiding a user around a custom JupyterLab workspace layout, for example. [To my mind, workspaces are the most useful and least talked about feature of the JupyerLab UI….] More generally, shepherd.js looks interesting as a generic website tour supporting Javascript package.) What I’m not sure about is the extent to which I could share, or proxy access to, of a WebRTC MediaStream that could be accessed live by a remote user.

Another way of sharing the content of a live notebook is to use the new realtime collaboration features in JupyterLab (see the official announcement/background post: How we made Jupyter Notebooks collaborative with Yjs). (A handy spin-off of this is that it now provides a hacky workaround way of opening two notebooks on different monitors.) If you prefer more literal screensharing, there’s also yuvipanda/jupyter-videochat which provides a server extension for proxying a Jitsi (WebRTC) powered video chat, which can also support screen sharing.

Author: Tony Hirst

I'm a Senior Lecturer at The Open University, with an interest in #opendata policy and practice, as well as general web tinkering...

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