On: I Wrote an Activitypub Server in OCaml: Lessons Learnt, Weekends Lost

[knjllppppp]

I've had a go at doing it in Go and the ActivityPub spec is so loosely defined that it's just a real challenge if you intend to actually unmarshal the JSON you receive

It's not completely impossible but you have to be okay with discarding a lot of unknown options or essentially reverse engineering the objects used by the servers you are federated with

That's not to say it's impossible, I was able to crawl the network successfully, but it hints at the reason that Mastodon and Pleroma use dynamic languages

I'd be very interested to see a flexible/complete AP implementation in any statically typed language

Fwiw WriteFreely is implemented in Go with go-fed but -- correct me if I'm wrong -- that library seemed more limited to me than what Pleroma and Mastodon support

[mariusor → knjllppppp]

I'm surprised you didn't find my library because I managed to create a statically typed vocabulary library for Go that maps the specification verbatim: https://pkg.go.dev/github.com/go-ap/activitypub#Object

It wasn't easy indeed, and it locked me out of some options to support execution time vocabulary extensions, but hey, it works and it's relatively easy to use.

[knjllppppp → mariusor]

I'm surprised I didn't find it, too! My google-fu must be getting rusty. Thanks for the link, I'll have to have a deep dive when I get the time :)

[mariusor → knjllppppp]

I hope you get to it. The library itself contains more than just the vocabulary part and I would be glad of more eyeballs on the problem. :D

[yawaramin → knjllppppp]

Here's the implementation described in OP: https://github.com/Gopiandcode/ocamlot

OCaml is a statically-typed language. It falls somewhere between Go and Haskell on the spectrum of type 'strength'.

[zimpenfish → knjllppppp]

> I'd be very interested to see a flexible/complete AP implementation in any statically typed language

Try Honk[1] or GotoSocial[2]?

[1] https://humungus.tedunangst.com/r/honk [2] https://github.com/superseriousbusiness/gotosocial

[mariusor → zimpenfish]

Neither is flexible, nor strives for completion. They are both implementations that try to map the ActivityPub vocabulary on an existing web-application domain.

They are not ActivityPub servers, but web-apps that use the ActivityPub vocabulary to federate, which is what I meant in the grandparent post when I mentioned the classic mistake of ActivityPub implementers. :D