If I wanted to mess around with ActivityPub c2s clients what's a server I can host that has support for it?

[box464@mastodon.social]

@tom I see others are pointing you in a similar direction, but funnily enough I tinkered with Social Web's ap-component test instance this afternoon!

Look at the sample client "acct-handler", too. That's what I tried today.

https://socialwebfoundation.org/2025/05/28/ap-components/

https://github.com/social-web-foundation/acct-handler

[thisismissem@hachyderm.io]

@tom yeah, activitypds is the research project name, but there's a bunch of upstream work in Fedify to enable C2S in Fedify, and then also to enable reusing the Fedify vocabularies (they take JSON-LD and convert into classes that Fedify understands, and handles serialisation to JSON-LD)

[thisismissem@hachyderm.io]

@tom basically the things I'm trying to solve in ActivityPDS are:
- an OAuth profile (based on AT Proto's OAuth profile)
- webfinger & DIDs & Handles
- what should a "PDS" do in the context of ActivityPub C2S, how much logic does it implement, or is it just a simple pipe?

[evan@cosocial.ca]

@tom https://github.com/evanp/onepage.pub/

[tom@tomkahe.com]

@evan oh yeah this should be perfect

[evan@cosocial.ca]

@tom I can also send you an invite code.

There's a chapter on the social API in the ActivityPub book.

https://evanp.me/activitypub-book/

[evan@cosocial.ca]

@box464 @tom awesome! Make sure to add issues or PRs as you come up with ideas.

[tom@tomkahe.com]

@evan I signed up to get notified for the print edition a few months ago, still prefer actually holding physical books haha

[evan@cosocial.ca]

@tom OK!

[mariusor@metalhead.club]

@tom I basically follow actors and that's how seeing posts by others in your /inbox works.

The frontend loads stuff directly through JavaScript fetch and needs all the mechanisms of that to work (and I imagine what you see might be things failing to load due to CORS rules being too restrictive on remote Mastodon instances)

I am not aware of any issues with receiving activities though, and in this process the objects themselves should be fully dereferenced to local copies.

I'll add a note about BOX compilation. Thanx.

[mariusor@metalhead.club]

@tom looking at the post of mine you linked, I realize you're probably thinking of regular object discovery, and there isn't any mechanism for it yet, or for viewing remote objects that haven't reached your inbox.

[mariusor@metalhead.club]

@julian yes, two of them:

https://rattlehead.bruta.link < where a bot posts daily metal releases scraped from the internet

https://marius.federated.id < where I write a bit about stuff and play with more expressive ActivityPub objects.

[tom@tomkahe.com]

@mariusor sorry I meant the reverse behavior, viewing Oni users/activities from my mastodon instance (or from mastodon.social) not viewing remote activities from oni

I.e. searching for https://marius.federated.id/outbox/1725894299052/object doesn't pull up the object in mastodon (and searching for the user doesn't bring that up either)

[tom@tomkahe.com]

@mariusor actually nevermind ignore me, searching for your federated id user seems to work so I must have something wrong with my network configuration, I'll do some debugging later

[mariusor@metalhead.club]

@tom I understand.

Indeed in the past two/three weeks I must have deployed something (or Mastodon made some changes) that regular objects posted by ONI aren't findable any more. The problem is that I don't have a development setup for mastodon on which to test what the problem is. :(

However the actors should still be available.

[mariusor@metalhead.club]

@tom a quick check list for you:

1. Check if the actor is publicly accessible from the internet.

2. Check if it has a RSA private/public key.

3. Check that if you have a proxy in front of ONI it doesn't mangle Accept/Vary/Content-Type headers.

4. Check that if you have a proxy the `/.well-known/webfinger` route is handled by ONI. (your proxy should forward all routes to ONI directly as a start)

[julian@community.nodebb.org]

mariusor@metalhead.club Can you use ActivityPub.academy? There is a logger built in so you can see the activities coming and going. It might help you debug why the ONI activities aren't being processed.