Hannibal is an experimental ActivityPub library for Go. Its goal is to be a robust, idiomatic, and thoroughly documented ActivityPub implementation that fits into your application without any magic or drama.
I would be honored for you to see if Hannibal works for your project. It is being used successfully in several production websites.
However, it is still subject to significant breaking changes. So, please reach out and I am happy to help you get things working in your own software. And, please be prepared for the ground to shift under your feet with newer versions.
Like the ActivityPub spec itself, Hannibal is broken into several layers:
https://www.w3.org/TR/activitypub/
This is not an ActivityPub framework, but a simple library that easily plugs into your existing app. Add ActivityPub behaviors to your existing handlers, and send ActivityPub messages to other servers.
https://www.w3.org/TR/activitystreams-vocabulary/
The vocab package includes the standard ActivityStream vocabulary, including names of actions, objects and properties used in ActivityPub.
https://www.w3.org/TR/activitystreams-core/
The streams package contains common data structures defined in the ActivityStreams spec, notably definitions for: Document, Collection, OrderedCollection, CollectionPage, and OrderedCollectionPage. These are used by ActivityPub to send and receive multiple records in one HTTP request.
This package also includes a lightweight wrapper around generic data structures (like map[string]any and []any) that makes it easy to access data structures within an ActivityStreams/JSON-LD document.
The metadata package holds what your server knows about a document, such as reply counts, relationships, and the current viewer's moderation labels. None of it is ever part of the document's wire value.
https://datatracker.ietf.org/doc/draft-ietf-httpbis-message-signatures
The sigs package creates and verifies HTTP signatures and Digests.
The banner is Hannibal in the Alps by Richard Barrett Davis (1782–1854). The work is in the public domain.
This library is a work in progress, and will benefit from your experience reports, use cases, and contributions. If you have an idea for making this library better, send in a pull request. We're all in this together! 🐘