Would running a Lemmy/kbin instance on your phone be feasible?
Libp2p or similar stack could be used to provide the phone instance an address, caching could be distributed among peers. Of course, as long as other servers also support libp2p.
ActivityPub is all about pushing content around to subscribing servers. It sort of expects the subscribers to always be online which would not work for a phone. Servers could resend missed events, but essentially you would miss every event that occurs while the phone is asleep or doesn’t have the app running.
Also, every event that occurs needs to be processed and stored whether or not you are actively looking at it so it would be a huge battery drain while it was running.
It is definitely a service best run on an always-on server with a client application in a phone just asking the server for the latest stuff on-demand.
Events could be cached on the p2p network, so the phone only pings its peers for new content (mind the existing servers would be peers on the network).
Then the p2p network is really the “server” and the phone is still just a client. I’m also not sure that a p2p network could be queried very well because something would have to be able to produce aggregated and sorted results. It isn’t like pulling one file from a swarm. It would be like a blockchain and the phone would have to download the whole dataset from the p2p network before running queries on it.
What you are talking about sounds kind of like the Nostr protocol. It is a distributed social network trying to solve the same problem that ActivityPub is but in a slightly different way. All the events are cached on multiple relays and the client applications query those relays looking for information that gets aggregated and sorted on the client however it wants.
as others have mentioned there are storage and battery concerns but also Lemmy works best when its consistently available. Then theres the whole roaming IP problem if youre moving on cell networks. Federated instances and communities often won’t be able to find you for updates.
Most people don't come here to see archival stuff, so it wouldn't be so bad if the p2p network cached ephemerally (time limit or a size limit). Old content could still be reached on servers designed to cache old stuff.
I think it would be, but not in the way you're thinking.
ActivityPub is based on servers with domain names and accessible IP addresses communicating with each other. It's mandatory based on the fundamental design of the standard.
So if you were running one of the phones that can run a straight linux distribution, and you connected it to a permanent internet connection as a web server and copy of lemmy with a domain name, then it's possible. But it's no longer a phone, it's a server with the form factor of a phone.
I dunno. If you could run some distro like mobian on some phone with an 8 core processor, could be a decent choice for a little instance.
I think you'd want to use a phone with USB C then use a powered USB-C dock with wired ethernet, but get to square 0 and I bet you'd have something that could really sit there just serving for a long time. I'd be a little concerned with IO access since the internal MMC would be constantly hammered, but there are USB-C external drive enclosures you could easily use that for storage and not have to worry about mutilating your phone's mmc.
Part of me wants to try sometime just to prove it can be done.