kopper [they/them]

not much beyond “look at what other apps you’re trying to interoperate with output and try to reverse engineer your way through”. reading through the sources of other apps may be a good idea.

some links that may get you started, picked from https://socialhub.activitypub.rocks/t/guide-for-new-activitypub-implementers/479 :

• https://flak.tedunangst.com/post/ActivityPub-as-it-has-been-understood
• https://www.w3.org/community/reports/socialcg/CG-FINAL-apwf-20240608/
• https://swicg.github.io/activitypub-http-signature/
• https://seb.jambor.dev/posts/understanding-activitypub/
• https://tinysubversions.com/notes/reading-activitypub/

and depending on which ecosystem you’re targeting:

• https://docs.joinmastodon.org/spec/activitypub/
• https://join-lemmy.org/docs/contributors/05-federation.html

counter intuitively, avoid reading the specs if you’re looking to federate with existing software. the official specs are… extremely lacking beyond giving you the bullets to shoot yourself in the foot with (half of what little it defines goes unused in the real world, important things like “how do i know this activity is sent by the person it claims to be” is completely undefined (hint: everyone has more or less settled on http signatures).

once you get something federating, you can then look in the specs in an attempt to learn the concepts in depth, but writing code following the specs will result in code that simply won’t federate.

A lot of it boils down to most fedi software not being “native” and only having federation designed more-or-less as an afterthought addition on top of a traditional centralized-ish system (even for ones that have federation from the get-go). Meaning you make assumptions like “it’s fine if I deletes the replies of a post if the post gets deleted”.

This, combined with how much data you can’t re-load and have to track as it comes in (e.g. nobody implements the necessary collections to backfill who liked or boosted what from it’s source, so you have to track that implicitly through Like and Announce activities), makes it extremely infeasible to implement while keeping the same user experience. Hell, even reply collections needed to backfill missing replies are a rarity (though a lot more common than the others given Mastodon implements them).

Additionally, people want the same user experience they’re used to in centralized systems, like search actually searching through everyone, globally. This is something I believe AP simply isn’t “intended” for. ATProto, for example, is much better in this specific regard (but comes at it’s own hefty costs, as an implementor).

I don’t blame the implementors for doing things this way. IMO it’s better to partially implement something like AP as an extension, as opposed to diving in head first into being AP-native. The standards are extremely vague and incomplete once you start looking below the shallow surface, and this way at least if a better protocol comes by migration (or multi-protocol federation) won’t be too difficult compared to if your source of truth was the same AS2 data you federated, the way AP intended you to.

Eh, I’d make the argument the fediverse is overly inefficient, way more than it has to be. (But that doesn’t seem to be the actual point of the post, instead rehashing the same “distribution = good” thing without bringing anything new to the table)

Here are just a few things that could be fixed without needing to centralize fedi:

• A vast majority of instance software will store all old remote non-media data (that could easily be re-fetched when needed) permanently, even if nobody has seen it in years.
• If you’re lucky enough to be on instance software that backfills replies (GoToSocial, the Iceshrimp rewrite as of a few days ago, Mastodon in an extremely limited capacity), it will be done slowly and recursively, when much better alternatives that don’t need to deal with easy-to-get-wrong recursion handing are possible. (There is work going on to improve this, but it may take a while for it to land on enough instance software to make a difference)
• The obvious thing everyone harps on: Abysmal media caching defaults.
• No batching of activities. And relatedly, all sent activities are individually re-signed for each instance on each delivery (to be fair, handling this in a privacy preserving way is hard)
• No batching of fetches.
• RSA, just to make the above signature situation even worse
• Mastodon. Just in general. It’s by far the most heavyweight fedi software I know of, running on a synchronous and poorly threaded tech stack that’s is not very adequate to the fairly IO bound (when not using authorized fetch) and very concurrent AP use case. Running Mastodon for any instance less than ~500 active users is extremely overkill and you’d likely be suited with other, lighter, instance software if you don’t need any of the features that are Mastodon exclusive (which there aren’t that much of).
• Pleroma database rot, an exemplar of why the C2S advocates’ model of “store the raw JSON for everything” is a terrible idea (thankfully the C2S model hasn’t taken off enough to be important)

All other devs jumped ship. I think both Iceshrimp and Sharkey were launched by former Firefish devs (at least one of them was, Iceshrimp being a former hard fork of Firefish which was quickly rebased into a more up-to-date Misskey soft fork

Iceshrimp (Misskey fork) did not rebase their version of Misskey. They’re still based on the same Misskey v12 era code from Firefish and there’s no interest in significantly updating the JS version (as it’d make migration harder) now that the rewrite is well underway and (in my potentially biased opinion) quite promising.

[…] This is far from done which means it’s even farther from being daily-driveable.

If you’re on a single-user instance, and can limit yourself to apps targeting the Mastodon API, it’s quite usable. The web frontend still needs a fair chunk of work, and moderation tooling required for larger instances are still not there yet. (But there’s enough to fend off spam)

Iceshrimp was designed for stability which is also why a number of Firefish features had been kicked out. It itself is on maintenance for as long as it will continue to exist, which won’t be that long.

The only features kicked out from the Misskey fork were, from what I remember, post imports (which were broken and leaked DMs (Sharkey’s on the other hand should work fine, as their implementation is unrelated to the Firefish one)), and the centered view in the web front-end. The rewrite may end up removing more features, it’s still not exactly clear as more important foundational work is needed before decisions like that can be made.

Sharkey used to be the king of features, but at the cost of reliability. Especially Sharkey’s Mastodon API implementation is infamously bad. The Sharkey community has been waiting for someone to step up and develop a completely new Mastodon API implementation for Sharkey for I don’t know how long.

Sharkey’s Mastodon API was I believe more or less a direct port of the old Firefish one. (And, yeah, it’s not in a pretty state right now.) Firefish’s implementation has since gotten replaced with the implementation from Iceshrimp some time after Firefish was handed off to Naskya (which may just be the only Mastodon API implementation on Misskey-based software that actually works).

Also, the Sharkey devs lost a whole lot of community support when they collected donations for a server for Sharkey purposes and then took the money to set up a Minecraft server. Make of that what you want.

This is way too much of an oversimplification that I would plain remove this claim altogether. All I can say is that Sharkey/transfem.social has had a change of ownership and things are more or less resolved now.

And then there’s CherryPick. AFAIK, it’s a Japan-based Sharkey soft-fork in which a whole lot of Misskey and Sharkey issues have been fixed; don’t ask me for details, I only know this stuff from hearsay. Basically, CherryPick is Sharkey in good. Or in better.

CherryPick is older than Sharkey, and Korean (from what I know, anyway)