activitypub: implement IR-level considerations for Listen activities

lib/pleroma/web/activity_pub/activity_pub.ex

@@ -248,6 +248,26 @@ def create(%{to: to, actor: actor, context: context, object: object} = params, f
     end
   end
 
+  def listen(%{to: to, actor: actor, context: context, object: object} = params) do
+    additional = params[:additional] || %{}
+    # only accept false as false value
+    local = !(params[:local] == false)
+    published = params[:published]
+
+    with listen_data <-
+           make_listen_data(
+             %{to: to, actor: actor, published: published, context: context, object: object},
+             additional
+           ),
+         {:ok, activity} <- insert(listen_data, local),
+         :ok <- maybe_federate(activity) do
+      {:ok, activity}
+    else
+      {:error, message} ->
+        {:error, message}
+    end
+  end
+
   def accept(%{to: to, actor: actor, object: object} = params) do
     # only accept false as false value
     local = !(params[:local] == false)

lib/pleroma/web/activity_pub/utils.ex

@@ -20,7 +20,7 @@ defmodule Pleroma.Web.ActivityPub.Utils do
   require Logger
   require Pleroma.Constants
 
-  @supported_object_types ["Article", "Note", "Video", "Page", "Question", "Answer"]
+  @supported_object_types ["Article", "Note", "Video", "Page", "Question", "Answer", "Audio"]
   @supported_report_states ~w(open closed resolved)
   @valid_visibilities ~w(public unlisted private direct)
 
@@ -581,6 +581,21 @@ def make_create_data(params, additional) do
     |> Map.merge(additional)
   end
 
+  #### Listen-related helpers
+  def make_listen_data(params, additional) do
+    published = params.published || make_date()
+
+    %{
+      "type" => "Listen",
+      "to" => params.to |> Enum.uniq(),
+      "actor" => params.actor.ap_id,
+      "object" => params.object,
+      "published" => published,
+      "context" => params.context
+    }
+    |> Map.merge(additional)
+  end
+
   #### Flag-related helpers
   @spec make_flag_data(map(), map()) :: map()
   def make_flag_data(%{actor: actor, context: context, content: content} = params, additional) do

test/web/activity_pub/activity_pub_test.exs

@@ -257,6 +257,42 @@ test "adds an id to a given object if it lacks one and is a note and inserts it
     end
   end
 
+  describe "listen activities" do
+    test "does not increase user note count" do
+      user = insert(:user)
+
+      {:ok, activity} =
+        ActivityPub.listen(%{
+          to: ["https://www.w3.org/ns/activitystreams#Public"],
+          actor: user,
+          context: "",
+          object: %{
+            "actor" => user.ap_id,
+            "to" => ["https://www.w3.org/ns/activitystreams#Public"],
+            "artist" => "lain",
+            "title" => "lain radio episode 1",
+            "length" => 180_000,
+            "type" => "Audio"
+          }
+        })
+
+      assert activity.actor == user.ap_id
+
+      user = User.get_cached_by_id(user.id)
+      assert user.info.note_count == 0
+    end
+
+    test "can be fetched into a timeline" do
+      _listen_activity_1 = insert(:listen)
+      _listen_activity_2 = insert(:listen)
+      _listen_activity_3 = insert(:listen)
+
+      timeline = ActivityPub.fetch_activities([], %{"type" => ["Listen"]})
+
+      assert length(timeline) == 3
+    end
+  end
+
   describe "create activities" do
     test "removes doubled 'to' recipients" do
       user = insert(:user)