[Suggestion] Support liked collection

[bbvch13531]

Support liked collection for showing user's like posts.
ActivityPub protocol already has it as an optional property.

Considering user privacy, showing liked collection only for self might be a solution.
ActivityPub-Liked Collection

[dahlia]

This is an interesting suggestion, but there's a fundamental challenge with implementing liked collections in ActivityPub that we should consider carefully.

The core issue is around authentication and privacy. While ActivityPub technically supports client-to-server (C2S) interactions, the reality is that almost all ActivityPub implementations today only use server-to-server (S2S) communication. In S2S, servers authenticate each other using HTTP Signatures, but there's no standardized way for individual clients to authenticate themselves when accessing their own liked collection through ActivityPub endpoints.

This creates a trilemma: the ActivityPub spec suggests that liked collections should be discoverable and accessible, but for privacy reasons, we'd want to restrict access to only the user themselves. Without proper C2S authentication mechanisms being widely adopted, we'd either have to:

1. make liked collections completely public (privacy concern)
2. keep them entirely private and not expose them via ActivityPub (breaking interoperability)
3. implement our own authentication layer beyond the ActivityPub standard

Each approach has significant trade-offs that we should discuss as a community before implementation.

[bbvch13531]

Thank you for your response. It seems that C2S communication and authentication needs to be discussed first.

It should considered whether HackersPub's future plans include C2S authentication, or whether HackersPub plans to support other personal features (bookmarks, personalized settings) beyond the ActivityPub spec.

I have another question: if own authentication layer is implemented, then doesn't it breaking interoperability of ActivityPub?

[dahlia]

Great questions! Let me address them:

Regarding C2S authentication: While we do have long-term plans to implement C2S support, it's not on our immediate roadmap. The ecosystem needs more time to mature and standardize around C2S patterns.

For personal features like bookmarks and personalized settings: These don't necessarily need federation, so we can implement them through our own API without worrying about ActivityPub interoperability. They would be local-only features accessible through our web interface.

As for your concern about breaking interoperability with a custom authentication layer—it's a nuanced issue. If we implement something proprietary just for Hackers' Pub, then yes, it would break interoperability. However, if we develop a solution and propose it as a FEP (Fediverse Enhancement Proposal) for broader adoption, we could actually contribute to improving the ecosystem's interoperability. This would be similar to how other implementations have introduced features that later became de facto standards.

The key is to balance immediate user needs with long-term ecosystem health. We could start with a minimal implementation (perhaps making liked collections completely private for now), then evolve the solution as the community develops better standards for these use cases.