I think the #ActivityPub client-to-server API is extremely important and underrated. I'm glad to see the SWF and W3C group prioritizing it, because I think it has the potential to fix something that's kind of broken on the #Fediverse: too many accounts, on too many platforms that really ought to be clients.

Here's the rub, though: you need the big players in the space to support it. Mastodon needs to support it. Pixelfed and PeerTube need to support it.

So, how do you get the big existing projects to all implement it? How do you justify it?

Would love to hear what @evan@cosocial.ca thinks about this.

@deadsuperhero

I am heart to heart with you on this, friend.

@deadsuperhero so, here's my best bet. I can be wrong!

1. Get some servers to implement the API well.
2. Get some must-have clients that run on those servers. This shows the value of the API.
3. Our leading servers shift to supporting it.

That may work; I don't know. It's my best bet right now!

I want to note that WordPress is working on the API!

@evan@cosocial.ca Yeah, I mostly agree with this. It's just that the buy-in is a little bit of a chicken and egg problem. You need servers to adopt it, but you need a compelling first mover. Bonfire, maybe?

The spec definitely needs love, too. I think one of the harder things is building a timeline out of inbox activities. I feel like maybe a future version of the API could specify timelines somehow, whether it's an endpoint or some kind of basic query? Maybe there's even a way to implement alternative timelines at that level?

These are all just guesses on my part, but I feel like this could be a gateway to universal custom feeds.

Does the inbox have to map to a timeline, specifically? Mastodon called this out as being difficult to do because you would have to real-time parse the inbox every time you wanted to load the timeline.

Of course one could always reduce the inbox into a single timeline and serve that instead, but then we're braching out with our own proprietary APIs again.

Is that ok?

@deadsuperhero@social.wedistribute.org @evan@cosocial.ca

@julian@activitypub.space @general@activitypub.space @evan@cosocial.ca Again, this is sort of why I'm advocating for supporting timelines as a concept in the ActivityPub API. Instead of repeatedly parsing the inbox, we could do exactly what you're saying with some kind of representation of a timeline. Even if it's just plain old algorithmic time-sort.

On the other hand, however... If the ActivityPub API were used in an S2S context, enabling something like NodeBB to send activities on behalf of a Mastodon user, then it wouldn't matter that there is no GET /timeline, because all you need is POST /outbox and the Mastodon API handles their end.

Vice versa, NodeBB would use its own API to render a /world feed.

@deadsuperhero@social.wedistribute.org @evan@cosocial.ca

@julian @deadsuperhero @evan

Can't help but wonder about terminology use and abstractions they indicate. Nowhere in the specs is there mention of 'timeline' and neither of 'feed' (except as example use in AS).

I feel we started with powerful specs to be able to model *any* social networking use case. But where the specs had blanks gradually the impls filled these in with leaky abstractions such that fedi is now hammered into a very narrow social media microblogging domain.

If an app needs "Timeline" and "Feed" concepts, then it should model them. Given the actor-based nature of AP they might be actors, or whatever is best. These concept are about solution development, i.e. what is built on top of the protocol, and not indicative of core protocol capabilities.

There's so much confusion on "where does the protocol end vs. where does my app design start".

SDK's should offer "Addressable actors exchanging msgs with object payload", and hide all impl details for the solution developer.

@smallcircles @julian @deadsuperhero we call them collections.

https://www.w3.org/TR/activitypub/#collections

@julian@activitypub.space @general@activitypub.space @evan@cosocial.ca Again, this is sort of why I'm advocating for supporting timelines as a concept in the ActivityPub API. Instead of repeatedly parsing the inbox, we could do exactly what you're saying with some kind of representation of a timeline. Even if it's just plain old algorithmic time-sort.

@evan @julian @deadsuperhero

Except when they are called other names instead

A timeline is a different thing than a collection imho. And an AS collection has some very particular functionality, which if I model a timeline in my app may not supported (e.g. reverse ordering).

Collection / 'timeline' is one of those words where sometimes they indicate an app domain, and sometimes a core protocol mechanism. Same is true with 'follow' which is sometimes a user action, sometimes indicates low-level publish/subscribe.

For core capabilities that must be part of the specs, in 'protocol space' it may be better to use terminology that is more common in messaging architectures and all the various architecture patterns that are involved. Perhaps idk we deal with a time-ordered event log or something like that.

@smallcircles @evan An AS2 Collection cannot be a timeline (in general). It’s not even ordered. An AS2 OrderedCollection (a subtype of Collection) might be ordered by time or not, so it’s also not a timeline (in general). When they are ordered by some time value (unspecified in AP) they are often called “streams” in the spec. The Mastodon content timelines are not the same as AP activity streams although a filtered AP stream can be transformed to a content timeline.

@steve I think
we need to emphasize that timelines can be built from regular collections, even unordered ones, by using some intermediate representations specific to the type of timeline that a client wants to render.

The fact that the specification does not directly support a mapping between a collection and a responsive timeline, *DOES NOT MEAN* one can't be built from it, only that it requires a little more effort on the client side.

My goto example is how rich mail clients allow responsive mailbox representations on top of a much less expressive collection method that IMAP provides compared to ActivityPub.

@smallcircles @evan

@smallcircles @evan An AS2 Collection cannot be a timeline (in general). It’s not even ordered. An AS2 OrderedCollection (a subtype of Collection) might be ordered by time or not, so it’s also not a timeline (in general). When they are ordered by some time value (unspecified in AP) they are often called “streams” in the spec. The Mastodon content timelines are not the same as AP activity streams although a filtered AP stream can be transformed to a content timeline.

@mariusor @smallcircles @evan I’m not sure I completely follow. A timeline is ordered by time. I agree that an unordered collection could be sorted by time to create a timeline. The AP OrderedCollection “stream” is a kind of rigid presorting that anticipates what an AP client would want. However, I also agree that even those could be reordered (by time or otherwise) and/or filtered in the client to provide custom views of the activity stream.

@steve @evan

I agree with what you say.

On the use of "stream(s)" I did a search in both specs, and it is only very sparsely used in the meaning of a stream rather than an Activity Streams document or object.

One time mentioned as "Activity Streams consumer" in #ActivityStreams core and another mention in the Security considerations section.

> Publishers or Consumers implementing Activity Streams as a stream of public data ..

And twice in #ActivityPub where it says both inbox and outbox where it mentions "the outbox stream", "the inbox stream", and one other mention in definition of "Social API" where it is said to provide a "social stream of the user's actor".

So I would not consider this formal language terminology right now. That said, it would be good to further formalize the concept of a Stream, as it is a higher-order concept that'll help lift discussions out of nitty gritty impl detail territory.

@steve yes, that's how I meant it. A client fetches as much of the collection as it can, then applies whatever rules it wants to transform the result into a "timeline" when the user asks for it.

This however most likely requires local caching of the collection to have decent latency.

@smallcircles @evan

@mariusor @smallcircles @evan Yes, it can be done in the client or the server, or both. I’d like to see an interoperable way to define custom timelines (a kind of user-defined timeline algo) that the server maintains. A Mastodon account list timeline is a super simple version of it, but AP could provide something much more powerful (advanced filtering, merging, ranking, …). Ideally, these could be shared and customized further on the client side.