Post · bonfire.cafe

@steve@social.technoetic.com · 4 days ago

@silverpill @mariusor @trwnh In principle, I like the general idea, but I think it's misleading to call this an "ActivityPub" server FEP since it doesn't conform to the ActivityPub specifications. You also recommend (require?) using the `result` property to describe server side-effects, but you don't describe *how*. I don't know how you expect to "force clients to specify them".

silverpill

@silverpill@mitra.social · 3 days ago

@steve @mariusor @trwnh

This FEP introduces new requirements to ActivityPub, and I will probably add more in the future. Does that make it non conformant?

In any case, I think calling it an ActivityPub server is appropriate.

Side-effects are activities, I will clarify that in the FEP. The value of result property can be an embedded activity, or an array of activities.

Clients either specify them, or they don't get any side effects.

silverpill

@silverpill@mitra.social · 3 days ago

@steve @mariusor @trwnh

This FEP introduces new requirements to ActivityPub, and I will probably add more in the future. Does that make it non conformant?

In any case, I think calling it an ActivityPub server is appropriate.

Side-effects are activities, I will clarify that in the FEP. The value of result property can be an embedded activity, or an array of activities.

Clients either specify them, or they don't get any side effects.

infinite love ⴳ

@trwnh@mastodon.social · 3 days ago

@silverpill @steve this actually raises an interesting question about "side effects" and where they live. in the AP spec it's rather muddled and i've talked before about the issue of "activities as content/notifications vs activities as procedure calls". i personally err toward having no side effects, which i think were kind of a mistake for the reason you bring up (generic servers can never be aware of extended side effects).

infinite love ⴳ

@trwnh@mastodon.social · 3 days ago

@silverpill @steve typically i've taken a view similar to IFTTT -- the activities describe things that happen, probably already happened. one or more listeners can do whatever they want with that information. CRUD is boring to me and i would rather do that with HTTP (POST/GET/PUT/DELETE); the more interesting activities are things like Listen (scrobbles) or Arrive (checkins) or Question (stackoverflow) or so on.

infinite love ⴳ

@trwnh@mastodon.social · 3 days ago

@silverpill @steve it sounds like you're describing an "AP server" whose primary functionality is not "publish activities" but rather "manage CRUD for objects and Add/Remove for collections", by taking the AP "side effects" for Create/Update/Delete/Add/Remove and and saying the outbox should also check as:result.

which is cool but should probably be disambiguated.

infinite love ⴳ

@trwnh@mastodon.social · 3 days ago

@silverpill @steve so maybe instead of "generic activitypub server" the FEP should be called something like "explicitly specifying side effects with the result property". it seems to me like the references to 2277 and fe34 are not strictly necessary to the core idea and a separate FEP could bundle them together into a profile, like "a profile for using outbox activities to manage objects and collections". not sure what the best name is because naming things is the hardest

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Steve Bate

@steve@social.technoetic.com · 3 days ago

@silverpill @mariusor @trwnh
> This FEP introduces new requirements to ActivityPub, and I will probably add more in the future. Does that make it non conformant?

Not at all. I was referring to the `Add` without an `object` to create a collection (instead of Create/Collection, I assume).

silverpill

@silverpill@mitra.social · 3 days ago

@steve @mariusor @trwnh Yes, this is wrong and I am going to replace Add with Create. I forgot that non-FEP-ae97 clients can't mint identifiers.

silverpill

@silverpill@mitra.social · 3 days ago

@steve @mariusor @trwnh Yes, this is wrong and I am going to replace Add with Create. I forgot that non-FEP-ae97 clients can't mint identifiers.

Ben Pate 🤘🏻

@benpate@mastodon.social · 4 days ago

@silverpill @mariusor @trwnh

I *love* this idea - especially in principle. I say that because I’m having a hard time wrapping my head around this and how it would be used in practice.

Do you think you could post an example workflow (or three) to demonstrate how this would work?

I get that objects could be added to client-defined collections (very cool) but if object/collection IDs don’t have predefined semantics, how will I know where to look to get the data I need?

silverpill

@silverpill@mitra.social · 4 days ago

@benpate Let's assume that my client is a music player. It publishes a Listen activity where object is an Audio. This activity should increase playCount on the Audio object.

One way to support this on the server side is to teach it about Listen, Audio and how to update playCount. This is how most existing servers are built.

But a server described in my FEP would work differently:

- It doesn't know anything about Listen, Audio or playCount.
- Upon receiving Listen, it will recognize it as an activity, and embedded Audio as an object.
- Since this is not a CRUD operation, it will not check permissions.
- If Listen activity has a result property, the server will process that activity as well.
- If result is an Update activity, the server will recognize it as a CRUD operation and will check permissions: Update.actor and Audio.attributedTo must be the same.
- The server will save both activities, Listen and Update.
- Then it will deliver them to intended recipients (to and cc).

Effects are client's responsibility now, it must provide an Update activity if it wants to update playCount. There are other requirements too, for example all objects should have an attributedTo property, which is needed for permission checks.

But in this setup a single server can work with any kind of client.

@mariusor @trwnh

Ben Pate 🤘🏻

@benpate@mastodon.social · 4 days ago

Yes, I think I like the idea of clients being able to store data on the server however they like. It reminds me of this description of ATProto that I found recently: https://overreacted.io/a-social-filesystem/

I guess my question is: once I store my custom stuff in custom places on my server, how do I publish this so other people can find?

And, object IDs are usually defined by the server. So how would it work to say "create a collection named XYZ and add this object to it"?

@silverpill @mariusor @trwnh

A Social Filesystem — overreacted

Formats over apps.

silverpill

@silverpill@mitra.social · 3 days ago

@benpate Publishing process doesn't change much. A generic server should deliver activities to actors specified in to and cc fields. It should keep track of collections, such as followers collection, and "expand" them before delivery. This part is not different from the regular ActivityPub.

I think ID assignment should also work the same. In the FEP I proposed Add activity without object as a special activity for creating collections, but now I see that it will not work if IDs are minted by a server (no FEP-ae97).

Perhaps it should be a Create, after all, as @trwnh described in an adjacent comment. I was hesitant to use Create because this is a problem for FEP-ae97 clients (not a big one though).

@mariusor @trwnh

silverpill

@silverpill@mitra.social · 3 days ago

@benpate Publishing process doesn't change much. A generic server should deliver activities to actors specified in to and cc fields. It should keep track of collections, such as followers collection, and "expand" them before delivery. This part is not different from the regular ActivityPub.

I think ID assignment should also work the same. In the FEP I proposed Add activity without object as a special activity for creating collections, but now I see that it will not work if IDs are minted by a server (no FEP-ae97).

Perhaps it should be a Create, after all, as @trwnh described in an adjacent comment. I was hesitant to use Create because this is a problem for FEP-ae97 clients (not a big one though).

@mariusor @trwnh

silverpill

@silverpill@mitra.social · 3 days ago

@benpate

Changed it to Create: https://codeberg.org/fediverse/fep/pulls/770

@trwnh @mariusor @steve

Codeberg.org

FEP-fc48: Use Create activity to create collections

Clarify that side effects are activities.

silverpill

@silverpill@mitra.social · 3 days ago

@benpate

Changed it to Create: https://codeberg.org/fediverse/fep/pulls/770

@trwnh @mariusor @steve

Codeberg.org

FEP-fc48: Use Create activity to create collections

Clarify that side effects are activities.

infinite love ⴳ

@trwnh@mastodon.social · 4 days ago

@benpate @silverpill

> object ids are usually defined by the server

the server would need to know your namespace/prefix, then mint ids in that namespace. if that is a dns name, then you get dns portability. if it's an https uri, then you ideally need to support relative references and redirects.

"create a collection" can happen over any CRUD method supported. if you use AP as an API then this would be a Create(object.type=Collection) then you get HTTP 201 Created with a Location header.

infinite love ⴳ

@trwnh@mastodon.social · 4 days ago

@benpate @silverpill the thing is though, AP specifies the outbox's 201 Created response to return the Location of the *activity* and not the *object*, because AP is about publishing activities. we have some vague notion of a Create activity's "side effect" being to "create" the object, but this doesn't really make sense unless something is listening to Create activities and doing the CRUD procedure. the simplest way to do this is a "default client" or otherwise address an application actor.

infinite love ⴳ

@trwnh@mastodon.social · 4 days ago

@benpate @silverpill

once you get the Location header you are free to do whatever you want with it.

infinite love ⴳ

@trwnh@mastodon.social · 4 days ago

@benpate @silverpill @mariusor none of the IDs should have any semantics; from the outside, there is no distinction between a client managed or server managed collection. likes/shares/etc could be managed by a "client" like mastodon, or even a "default" one. it's not any more complex unless you want to vary the collection responses based on the request headers. for that you need a minimal dynamic layer with an access control policy of some sort. (WAC is the simplest, but ACP is more powerful)

infinite love ⴳ

@trwnh@mastodon.social · 4 days ago

@benpate @silverpill in a client managed followers collection i would Add you to my followers just like fedi instances currently do silently. "but how can you prove--" yes exactly, how can current fedi prove anyone is a follower either? you need the Follow+Accept pair to both be live without an Undo on either, right? and that's what leads to the "follow state machine" on fedi that drifts out of sync and leads to private posts being leaked to removed followers (which you can't officially do!)

julian

@julian@activitypub.space · 4 days ago

@silverpill@mitra.social I find it curious that this needs to be spelled out in an FEP.

Isn't a generic AP server one that ingests anything and shoves it into the outbox... like a mail transfer agent?

... then delivers it dutifully?

I mean, sure, you can do stuff in between, like spam detection, blocklists, etc etc etc...

My quick read through of the FEP (and it was quick, because it was a short FEP ) seems to confirm this.

silverpill

@silverpill@mitra.social · 4 days ago

@julian It looks simple on the surface, but in reality it is much more complicated than a non-generic server. In addition to activity transfer, generic server needs to maintain collections. First of all, a followers collection, which is often used as a delivery target. Then likes, shares etc. It needs to enforce permissions, to prevent actors on the same server from deleting each other posts.

This is doable if you only care about activities defined in ActivityPub. But then you want to introduce context collection. And then 50 other extensions. How to do that without special-casing every one of them?

This is where duck typing (FEP-2277) and unified security model (FEP-fe34) become really handy. No matter what the client sends, you can figure out what it is (an object, an actor, or a collection), and enforce permissions.

silverpill

@silverpill@mitra.social · 4 days ago

@julian It looks simple on the surface, but in reality it is much more complicated than a non-generic server. In addition to activity transfer, generic server needs to maintain collections. First of all, a followers collection, which is often used as a delivery target. Then likes, shares etc. It needs to enforce permissions, to prevent actors on the same server from deleting each other posts.

This is doable if you only care about activities defined in ActivityPub. But then you want to introduce context collection. And then 50 other extensions. How to do that without special-casing every one of them?

This is where duck typing (FEP-2277) and unified security model (FEP-fe34) become really handy. No matter what the client sends, you can figure out what it is (an object, an actor, or a collection), and enforce permissions.

marius

@mariusor@metalhead.club · 4 days ago

@silverpill lol, based on the "claims" at the begining, why do I feel like the "thanks" at the end should be in quotations?

Also I take umbrage with calling what I've been doing for the past 8 years as "being not difficult to build nor an interesting concept". I feel like, you and other developers having the benefit of dynamically typed programming languages, underestimate how that can be worked into robust APIs when you're limited by less versatile stacks.

silverpill

@silverpill@mitra.social · 4 days ago

@mariusor Mastodon supports all standard activities and has a wide variety of clients. I don't find softwares with similar capabilities impressive, although I respect your work (the only ActivityPub server-client project that is not a vaporware).

I doubt that language choice makes much difference, and Rust is not a dynamically typed language anyway. The difficulty you might be facing is likely due to JSON-LD.

The thanks was for your input with regards to collection management.

Raphael Lullis

@raphael@mastodon.communick.com · 4 days ago

@silverpill

> Mastodon supports all standard activities and has a wide variety of clients.

What happens when you send a "Offer" message to an actor on Mastodon? Can they accept it?

Can I create a group actor on Mastodon? Can I use this actor to boost other actor's posts and have it visible on a Lemmy client?

How can a Mastodon client ask the server to get a collection of all images with an specific tag?

@mariusor

silverpill

@silverpill@mitra.social · 4 days ago

@raphael

What happens when you send a "Offer" message to an actor on Mastodon?

The behavior of Offer activity is not described in ActivityPub, so Mastodon is not required to support it. Curiously, ActivityPub mentions Offer when it talks about the side effects of Accept:

The side effect of receiving this in an inbox is determined by the type of the object received, and it is possible to accept types not described in this document (for example, an Offer).

...This statement is not compatible with the idea of a generic server.

Can I create a group actor on Mastodon?

I don't know. But it can create Service actors, I guess it can be easily patched to allow creation of Group actors too.

Can I use this actor to boost other actor's posts and have it visible on a Lemmy client?

I think FEP-1b12 Announce is not compatible with ActivityPub. It has different side effects, doesn't update shares collection.

How can a Mastodon client ask the server to get a collection of all images with an specific tag?

Maybe something like /api/v1/timelines/tag/{tag}?only_media=true ?

@mariusor

Raphael Lullis

@raphael@mastodon.communick.com · 4 days ago

@silverpill

> I think FEP-1b12 Announce is not compatible with ActivityPub. It has different side effects, doesn't update shares collection.

Why?

Updating the shares collection is orthorgonal to the behavior expected from a Group actor that claims to support 1b12.

Sure, you can say that if the server does not update the shares collection, it's not fully compliant with AP APi, but there is nothing a Lemmy server to add every activity to the shares collection.

@mariusor

silverpill

@silverpill@mitra.social · 4 days ago

@raphael Nevermind, side effects wouldn't be a problem. However, it still doesn't seem to be compatible with ActivityPub... Because Announce activity is not defined in C2S context :)

https://www.w3.org/TR/activitypub/#client-to-server-interactions

@julian @mariusor

ActivityPub

The ActivityPub protocol is a decentralized social networking protocol based upon the [ActivityStreams] 2.0 data format. It provides a client to server API for creating, updating and deleting content, as well as a federated server to server API for delivering notifications and content.

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silverpill

@silverpill@mitra.social · 4 days ago

@raphael Nevermind, side effects wouldn't be a problem. However, it still doesn't seem to be compatible with ActivityPub... Because Announce activity is not defined in C2S context :)

https://www.w3.org/TR/activitypub/#client-to-server-interactions

@julian @mariusor

ActivityPub

The ActivityPub protocol is a decentralized social networking protocol based upon the [ActivityStreams] 2.0 data format. It provides a client to server API for creating, updating and deleting content, as well as a federated server to server API for delivering notifications and content.

julian

@julian@activitypub.space · 4 days ago

@silverpill@mitra.social said:

I think FEP-1b12 Announce is not compatible with ActivityPub.

Shots fired

Raphael Lullis

@raphael@mastodon.communick.com · 4 days ago

@silverpill @mariusor

> The behavior of Offer activity is not described in ActivityPub

You can still take the document and place in the target inboxes, leaving to the *client* to figure out what to do with it.

You don't need to describe the specific case if the general case (activities must be placed in the target inbox) is enough.

Is this your objection when you are talking about "Generic Servers"? Because if that is the case then I can definitely argue that my server is it.

silverpill

@silverpill@mitra.social · 4 days ago

@raphael Placing activities in the target inbox is not always enough, sometimes there are side effects.

In my FEP I discuss how we can deal with that.

There is more to it, see my response to @julian:

https://mitra.social/objects/019ca012-a698-5c2a-a6fa-a547373294cc

@mariusor

silverpill

@silverpill@mitra.social · 4 days ago

@raphael Placing activities in the target inbox is not always enough, sometimes there are side effects.

In my FEP I discuss how we can deal with that.

There is more to it, see my response to @julian:

https://mitra.social/objects/019ca012-a698-5c2a-a6fa-a547373294cc

@mariusor

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Raphael Lullis

@raphael@mastodon.communick.com · 4 days ago

@silverpill

> generic server needs to maintain collections.

If you are talking about "any arbitrary collection beyond followers/following/inbox/outbox/shares/likes". I'll disagree with you.

@julian @mariusor

silverpill

@silverpill@mitra.social · 4 days ago

@raphael

What happens when you send a "Offer" message to an actor on Mastodon?

The behavior of Offer activity is not described in ActivityPub, so Mastodon is not required to support it. Curiously, ActivityPub mentions Offer when it talks about the side effects of Accept:

The side effect of receiving this in an inbox is determined by the type of the object received, and it is possible to accept types not described in this document (for example, an Offer).

...This statement is not compatible with the idea of a generic server.

Can I create a group actor on Mastodon?

I don't know. But it can create Service actors, I guess it can be easily patched to allow creation of Group actors too.

Can I use this actor to boost other actor's posts and have it visible on a Lemmy client?

I think FEP-1b12 Announce is not compatible with ActivityPub. It has different side effects, doesn't update shares collection.

How can a Mastodon client ask the server to get a collection of all images with an specific tag?

Maybe something like /api/v1/timelines/tag/{tag}?only_media=true ?

@mariusor

Raphael Lullis

@raphael@mastodon.communick.com · 4 days ago

@silverpill

@mariusor

Also, reading FEP-aea97 and I don't see anything there that my modest little server made with a "dynamic language" doesn't do already.

And It's not even like what I am doing is novel or incredibly diffiicult. If you spent a little time embracing RDF and JSON-LD, you could take a look at what Vocata did and you'd see how easy it can be implement the AP API.

silverpill

@silverpill@mitra.social · 4 days ago

@raphael

what Vocata did

This project is often brought up as an example of a generic server, but it never reached production stage. The last commit was in 2023.

It is one thing to have an idea and build a prototype, and a completely different thing to build an application that is secure and interoperates with the rest of the network.

@mariusor

infinite love ⴳ

@trwnh@mastodon.social · 4 days ago

@silverpill @raphael @mariusor

> neither is it an interesting concept

> interoperates with the rest of the network

look, we clearly have different goals here. your goal is to interoperate with the mastodon network. my goal is to publish activities to my website. mastodon doesn't even support all the activities defined in AS2-Vocab. a generic server supports *any* activity, even those not defined by AS2. the network i want to interoperate with isn't mastodon, it's the web.

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Raphael Lullis

@raphael@mastodon.communick.com · 4 days ago

@silverpill

That's what I saying, though: I took the *ideas* from Vocata and implemented in a way that can work in production.

@mariusor

Raphael Lullis

@raphael@mastodon.communick.com · 4 days ago

@silverpill @mariusor

> And yes, the difficulty is indeed in massaging JSON-LD documents into strongly typed data that are meaningful for library consumers.

Maybe this could help: https://activitypub.mushroomlabs.com/topics/reference_context_architecture/

References and Context Models - Django ActivityPub ToolKit