ActivityPub

ActivityPub Library for elixir.

WORK IN PROGRESS, TESTING FEDERATION WITH DIFFERENT IMPLEMENTATIONS IS UNDERWAY

Installation

1. Add this library to your dependencies in mix.exs

defp deps do
  [...]
  {:activity_pub, git: "https://github.com/bonfire-networks/activity_pub.git", branch: "stable"} # branch can "stable", or "develop" for the bleeding edge
end

2. Create an adapter module. To start, one created at lib/my_app/adapter.ex might look like

defmodule MyApp.Adapter do
  @moduledoc """
  Adapter functions delegated from the `ActivityPub` Library
  """

  @behaviour ActivityPub.Federator.Adapter
end

Note that, due to the defined @behavior, Elixir will warn you that the required functions

• base_url/0
• get_actor_by_id/1
• get_actor_by_username/1
• get_follower_local_ids/1
• get_following_local_ids/1
• get_redirect_url/1
• handle_activity/1
• maybe_create_remote_actor/1
• maybe_publish_object/2
• update_local_actor/2
• update_remote_actor/1

have not yet been implemented though you will be able to start your app. Defining these allows ActivityPub to handle ActivityPub HTTP and database calls and operations. An example of an implemented adaptor can be found [here](https://github.com/bonfire-networks/bonfire_federate_activitypub/tree/main/lib/adapter "Link to file hosted on GitHub").

Then set it in config

config :activity_pub, :adapter, MyApp.Adapter

3. Set your application repo in config

config :activity_pub, :repo, MyApp.Repo

4. Create a new ecto migration and call ActivityPub.Migration.up/0 from it

5. Inject AP routes to your router by adding use ActivityPub.Web.Router to your app's router module

6. Copy the default AP config to your app's confix.exs

config :activity_pub, :mrf_simple,
  media_removal: [],
  media_nsfw: [],
  report_removal: [],
  accept: [],
  avatar_removal: [],
  banner_removal: []

config :activity_pub, :instance,
  hostname: "example.com",
  federation_publisher_modules: [ActivityPub.Federator.APPublisher],
  federation_reachability_timeout_days: 7,
  federating: true,
  rewrite_policy: []

config :activity_pub, :http,
  proxy_url: nil,
  user_agent: "Your app name",
  send_user_agent: true,
  adapter: [
    ssl_options: [
      # Workaround for remote server certificate chain issues
      partial_chain: &:hackney_connect.partial_chain/1,
      # We don't support TLS v1.3 yet
      versions: [:tlsv1, :"tlsv1.1", :"tlsv1.2"]
    ]
  ]

7. Change the hostname value in the instance config block to your instance's hostname

8. If you don't already have Oban set up, follow the Oban installation intructions and add the AP queues:

config :my_app, Oban, queues: [federator_incoming: 50, federator_outgoing: 50, remote_fetcher: 20]

Now you should be able to compile and run your app and move over to integration.