Hi. I'm new to CouchDB, but I was just chatting with Noah on IRC about how IRC sucks and we need to replace it and whether we could do that using CouchDB. He mentioned this thing Chris did four years ago called Toast: <http://jchrisa.net/drl/_design/sofa/_list/post/post-page?startkey=%5B%22Simple-Wins%22%5De> Right now Skype chat is basically the best thing out there that I've seen, but it's proprietary. It has the following features I like: * Real-time: people normally see your lines within less than a second after you send them. * Peer-to-peer: you don't have to install or manage software on a server to make it work, and it knows how to traverse NATs. (Skype, Inc., does maintain a centralized authentication service, which I regard as a significant drawback.) * Replicated: you can look at chat history and add chat lines when you're offline. When you reconnect to the people you're talking to, all the lines get sent. This is important not mostly because I'm trying to chat while I'm on an airplane but because I don't want to lose messages when my network gets disconnected, and because I switch between devices and want to be able to see messages I typed on my laptop on my cellphone and vice versa. (As far as I can tell, the POP-not-IMAP nature of XMPP makes this impossible for XMPP chats.) * Unified-UI: you can chat with many different people or groups of people at once using the same app, and see e.g. a list of chat channels where you have unread messages. * Encrypted: your ISP can't read your chat messages. * Secure: the people you're chatting with can't subvert your chat software to e.g. snoop on your other chats. * Correct: unlike IRC, doesn't truncate your lines at arbitrary places if they get too long. * File transfers: you can send screenshots and stuff to other people, including everybody in a group chat. * Cross-platform: versions for both GNU/Linux and Android. So I'm trying to get a sense of whether there's something out there that would make this feature set easy to replicate. And maybe CouchDB is it? Or do I need to build something from scratch? [Noah suggested](http://swhack.com/logs/2012-11-24#T02-25-22) making each chat line a new document, using continuous replication, creating a mapreduce view using datetime as a key and pulling the most recent 40 messages, and using the _changes feed to get Comet updates to the browser asynchronously. That sounds pretty reasonable to me, but the following questions occur to me: * I'm behind NAT. If you're behind NAT too, how can we set up continuous replication between our CouchDB instances? Is there STUN support for CouchDB replication yet? * Do I need to create a new CouchDB database for every chat room? Is there any problem with having 20 or 30 databases on my netbook talking at once? * How about if I want to have a single Comet connection from my browser to all of them at once? (Browsers won't let you have 30 Comet connections to localhost.) * Are there security concerns I need to think about? Like, how do I make it so that I can update my DHTML UI, and maybe even automatically get updates from someone else, but not *everybody* I chat with can update my DHTML UI to a version that spies on my chats? What are the security properties of the replication protocol? What if I need to kick someone out of a chat channel because they're spamming it? I think the ability to automatically update application code is necessary for decentralized applications (like email) to start to successfully compete with centralized ones (like Facebook) again, but although I have some ideas about how to do that securely, I don't feel like I've solved the problem because I haven't tried them in practice yet. Anyway, I don't know if anybody else thinks it's an interesting project, but it seems to me like every chat system out there today is basically unusably bad, and decentralized database replication with automatically incrementally updating views seems like the right substrate to build it on. ----- End forwarded message ----- -- To unsubscribe: http://lists.canonical.org/mailman/listinfo/kragen-tol ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE