2 Years Ago…

I finally got back with a new blog post 2 years since my initial experiments with the ActivityPub protocol.

Fortunately, the protocol has pretty much remained the same. The good news is that since two years ago, there are better and newer resources to kickstart the process of building an implementation.

ActivityPub Tutorial

One super useful resource that I have found is Timothy’s activity-pub-tutorial. It describes the minimal implementation required for an ActivityPub implementation to talk to other servers.

Notably, it includes a section on Mastodon’s new digest requirement which bit me when I was messing around with my own implementation two years ago…

Following this tutorial is probably the best and fastest way to get started.

Side Note on Digest Header

Mastodon requires the digest header which caught my off-guard two years back.

Instead of simply signing this signature text:

(request-target): post %s\nhost: %s\ndate: %s

It is now

(request-target): post %s\ndigest: SHA-256=%s\nhost: %s\ndate: %s'

Timothy’s tutorial includes instructions on how to implement it this new requirement, so you can follow it as you go along.