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Comment by d0m3 | Hacker News Reader

Nice article. I built my own online version of a turn based board game because none exists at the moment. I just want to play with my family so I didn't bother coding a server at all, instead all clients communicate their actions to all others so I naturally implemented the deterministic approach. I haven't thought about secret state so it's interesting to see a possible solution for that. Fun!

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I'm also writing an online version of a board game I like, to play with family and friends. I am about to start the networking part, and I actually intended to implement the deterministic approach, although I didn't know the concept had a name before reading the article. It's nice to read some validation that it is a good design.

I'm curious to know how you achieve not to need a server at all. How do you create the initial connection between clients without a server to negotiate NATs and things like that?

If your game is web-based, you could leverage WebRTC - where you only need to share a unique link between users - see peerjs (https://peerjs.com/) or croquet.io (https://croquet.io/docs/croquet/)

If you target desktop, should be fine, but mobile users tend to use cell towers which are on Symmetric NAT, which would require a TURN server on top of the WebRTC.

I'm targeting desktop, but your point is good to know, thanks. I will keep it in mind.

Even on desktop you run into people with weird configs. For example my router will not allow mDNS to work but my ISP NAT is pretty good so I can connect two machines as long as they’re not on the same network! In the end you almost always will need a relay to guarantee connectivity for any random pairing of participants in a large enough population.

The good news is that WebRTC is perfectly straightforward if all you want to do is to connect to a server on the open internet.

It is web-based, yes. I was aware of WebRTC but assumed I would need a least to host the server myself. I'm looking at the links you provided and they seem very interesting. Thank you.

Initially I thought I would be able to do it with webRTC but it turns out you still need some kind of specific server to connect clients. Instead I cheated a little bit and used a messaging service https://ably.com/. It was easy to setup and use, and their free plan is generous. Another thing I didn't achieve is to find a RNG I could configure with a seed, so amongst my client I have a special one, the "host" who is drawing the cards, etc. Overall it's been working really well. There is one thing that is particularly difficult without a server, that is debugging. Especially if using a mobile phone, you're in the dark when a bug happens. And with Ably and the free tier, you have to be connect in debug mode beforehand to see the logs, very unpractical. Good luck with your game!

Not sure how far along you are, but I could help you build the game if you are willing to try making it for acos.games. I built a simulator that can help speed up development which is done in React and NodeJS.

Thank you for the suggestion. However I am close to finishing all the game mechanics, just on a single computer (the game has no secret knowledge so it playable on a single computer or, at worst, via screen sharing). Also I'm implementing it in Scala.js with Indigo [1], and part of the reason for the project is to have an excuse to learn Indigo, so i wouldn't change the technical stack.

Thank you, though. It seems like a nice platform!

[1] https://indigoengine.io/

I think it could be made compatible. Will look into indigo engine, didn't know about it until now. Thanks and good luck!

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