Multiplex via CDN - docs

[WesleyTheGeolien]

I was able to get this working via calling a CDN and no installs (This is mainly to have a standalone html file that works).

Not sure if it could be added to the docs but I ended up using:

<script defer src="https://cdn.jsdelivr.net/npm/reveal-multiplex@0.1.0/client.min.js"></script>

defer was important else I was getting an error with Reveal.getConfig not being declared. Hope this can be of use to someone

[jmuheim]

Can you give some more details? I'm quite overwhelmed with the installation instructions. Does what you suggest really work without installing anything node modules etc.?

[WesleyTheGeolien]

Hello @jmuheim

I was able to get everything up and running in a standalone html file without any installations yes.

At the bottom of the body tag I added:

<script
      defer
      src="https://cdn.jsdelivr.net/npm/reveal-multiplex@0.1.0/client.min.js"
    ></script>
    <script src="https://reveal-multiplex.glitch.me/socket.io/socket.io.js"></script>
    <script defer src="https://reveal-multiplex.glitch.me/master.js"></script>
    <script>
      // More info about initialization & config:
      // - https://revealjs.com/initialization/
      // - https://revealjs.com/config/
      Reveal.initialize({
        hash: true,

        // Learn about plugins: https://revealjs.com/plugins/
        plugins: [RevealMarkdown, RevealHighlight, RevealNotes],
		multiplex: {
			// Example values. To generate your own, see the socket.io server instructions.
			secret: null, // Obtained from the socket.io server. Gives this (the master) control of the presentation
			id: 'XXXXXX', // Obtained from socket.io server
			url: 'https://reveal-multiplex.glitch.me/' // Location of socket.io server
		  },
      });
    </script>

You still need to generate the secret / id pair from the socket io server and inject the correct values. Also be careful between the client and server to use the correct js library. You can see the tags here: https://www.jsdelivr.com/package/npm/reveal-multiplex?tab=files for client and master.

P.S. I have a single standalone file of reveal from CDNs here: https://github.com/WesleyTheGeolien/revealjs_single_file it needs updating to later versions but it works(ed).

[jmuheim]

Very nice! I will give it a try.

		secret: null, // Obtained from the socket.io server. Gives this (the master) control of the presentation
		id: 'XXXXXX', // Obtained from socket.io server

Does the secret really need to be null here?

[WesleyTheGeolien]

Very nice! I will give it a try.

		secret: null, // Obtained from the socket.io server. Gives this (the master) control of the presentation
		id: 'XXXXXX', // Obtained from socket.io server

Does the secret really need to be null here?

The secret is set to null inside the client html (html that people viewing the presentation will see) and will be set for the "master" presentation that controls the clients.

[jmuheim]

Thank you, it seems to work for me, too!

Some additional notes (for anyone trying to do the same):

• Go to https://reveal-multiplex.glitch.me/ and generate a secret/socketId pair
• In one browser, load your Reveal.js presentation with secret: <your-secret> and id: <your-id>
  • This is the master presentation. It's the one that you will use for your presentation.
• In another browser, load the same Reveal.js presentation with secret: null and id: <your-id> (so exactly the same, except you don't specifiy the socket id)
  • This is the client presentation. It will follow the master.
  • You can have as many client presentations as you want. 👍

While testing, sometimes my presentations got very confused and seemed to randomly change slides automatically several times a second (kind of an endless auto-loop). I guess it has something to do if you (by accident) have several master presentations for some reason → they will "fight" against each other. 😆 I even had to re-generate a secret/socketId pair to get out of the loop. But as soon as you have configured everything properly, it seems to work very well!

PS: The original Multiplex docs recommend to generate two nearly identical slide decks: one with the secret (master) and one without (client). This feels like an unnecessary overload to me. As I'm generating my presentation using Pandoc inside a Ruby application, I can simply do the following:

if params[:master] = '1'
  html = html.gsub "id: null,", "id: 'feadb32854c6d675',"
end

This allows me to load the same presentation for both master and client:

• Master: http://localhost:3008/de/lessons/20?master=1#/%C3%BCbersicht (with master=1 param)
• Client: http://localhost:3008/de/lessons/20#/%C3%BCbersicht (no such param)

I know that this isn't very secure, as anyone watching over my shoulder could simply see the master=1 param and add it to their client presentation to take over control. But for tinkering around, this works fine. I will find a better solution later.

Thanks again for your help, Wesley. It's great to have this working without the need to set up anything additional. <3

[jmuheim]

UPDATE: It seems that opening the overview (Esc) causes the strange condition that I outlined above (randomly changing slides automatically). Any idea what's happening there?

After fiddling around a bit more, I see that this can also happen without opening the overview (Esc), but when simply toggling very quickly through slides. It seems that when something happens "too fast", then the mechanism gets confused somehow and I can only reset by closing the master presentation and re-open it. (Sometimes I seem to need to wait a moment until I can savely re-open it).

[jmuheim]

@WesleyTheGeolien I have found a severe bug, and I created a ticket here:

#44

Could you maybe try to reproduce it? Any idea on what's causing this? Meanwhile, I'm trying the Seminar plugin, which doesn't have this bug AFAIK.