lots of changes, untested

lib/vonbraun/activity_pub/handler.ex

@@ -19,11 +19,29 @@ defmodule Vonbraun.ActivityPub.Handler do
     end)
   end
 
-  @spec handle(%{type: String.t()}, map()) :: :ok | {:ok, atom()} | {:error, any()}
-  def handle(activity = %{"type" => type}, actor = %{}) when is_binary(type) do
-    Agent.get(__MODULE__, fn map ->
-      func = Map.get(map, type, fn _, _ -> {:ok, :type} end)
-      apply(func, [activity, actor])
+  @doc """
+  Passed a list of types, gets the first handler that applies to a type.
+  """
+  def get_first_matching_handler(types) when is_list(types) do
+    Agent.get(__MODULE__, fn handler_map ->
+      Enum.reduce_while(types, nil, fn
+        type, _ ->
+          case Map.get(handler_map, type) do
+            nil -> {:cont, nil}
+            func -> {:halt, func}
+          end
+      end)
     end)
   end
+
+  @spec handle(%{type: String.t()}, map()) :: {:ok, atom()} | {:error, any()}
+  def handle(activity = %{"@type" => types}, actor = %{}) when is_list(types) do
+    case get_first_matching_handler(types) do
+      nil ->
+        {:ok, :ignore}
+
+      func ->
+        apply(func, [activity, actor])
+    end
+  end
 end

lib/vonbraun/activity_pub/handler/accept.ex

@@ -5,43 +5,54 @@ defmodule Vonbraun.ActivityPub.Handler.Accept do
   alias Vonbraun.Util
   alias Vonbraun.Ecto.Schema.Actor
 
-  @verb "Accept"
+  @verb "https://www.w3.org/ns/activitystreams#Accept"
+  @follow "https://www.w3.org/ns/activitystreams#Follow"
 
   def type, do: @verb
 
-  def extract_follow_object_actor(%{"type" => "Follow", "actor" => actor_id})
-      when is_binary(actor_id) do
-    {:ok, actor_id}
+  defp is_follow_object?(%{"@type" => types}) when is_list(types), do: @follow in types
+
+  # The actor is specified here so we can just use it.
+  @spec extract_follow_object_actor_id(map()) :: :error | {:error, :not_found} | {:ok, binary()}
+  def extract_follow_object_actor_id(object = %{"actor" => actor_value}) do
+    if is_follow_object?(object) do
+      Util.get_only_id(actor_value)
+    else
+      {:error, :not_found}
+    end
   end
 
-  def extract_follow_object_actor(%{"type" => "Follow", "id" => provided_follow_activity_id})
-      when is_binary(provided_follow_activity_id) do
+  # Only the ID was provided, so extract actor from the ID.
+  def extract_follow_object_actor_id(object = %{"@id" => _}) do
     domain = Application.fetch_env!(:vonbraun, :domain)
     actual_activity_id_prefix = "https://#{domain}/id/follow:"
 
-    with ^actual_activity_id_prefix <> actor_id <- provided_follow_activity_id do
-      {:ok, actor_id}
+    with {:ok, provided_follow_activity_id} <- Util.get_only_id(object),
+         ^actual_activity_id_prefix <> raw_actor_id <- provided_follow_activity_id do
+      {:ok, URI.decode(raw_actor_id)}
     else
       _ ->
         {:error, :not_found}
     end
   end
 
-  def extract_follow_object_actor(_) do
+  def extract_follow_object_actor_id(_) do
     {:error, :not_found}
   end
 
   # Lots of kinds of things can be accepted but for right now only follows.
   def handle(
         %{
-          "type" => @verb,
-          "actor" => actor_id,
-          "object" => object = %{"type" => "Follow"}
+          "actor" => actor_value,
+          "object" => object_value
         },
         %{}
       ) do
-    with {:actor, {:ok, follow_actor_id}} <- {:actor, extract_follow_object_actor(object)},
-         {:match, true} <- {:match, follow_actor_id == Util.my_id()},
+    my_id = Util.my_id()
+
+    with {:object, {:ok, object}} <- {:object, Util.get_only_property(object_value)},
+         {:actor, {:ok, ^my_id}} <- {:actor, extract_follow_object_actor_id(object)},
+         {:actor_id, {:ok, actor_id}} <- {:actor_id, Util.get_only_id(actor_value)},
          {:asked, {:ok, %Actor{:blocked => nil, :following_state => "accepted"}}} <-
            {:asked, Actor.mark_pending_follow(actor_id, "accepted", force: true)} do
       Logger.info("Now following: #{actor_id}")
@@ -55,7 +66,7 @@ defmodule Vonbraun.ActivityPub.Handler.Accept do
 
       {:asked, {:ok, %Actor{:blocked => nil, :following_state => following_state}}} ->
         Logger.error(
-          "Weird following state after received Accept: #{following_state} from actor: #{actor_id} this should not happen."
+          "Weird following state after received Accept: #{following_state} from actor: #{inspect(actor_value)} this should not happen."
         )
 
         {:error, :following_state}
@@ -63,7 +74,10 @@ defmodule Vonbraun.ActivityPub.Handler.Accept do
       {:actor, {:error, _error}} ->
         {:ok, :unauthorized}
 
-      {:match, false} ->
+      {:actor_id, :error} ->
+        {:ok, :unauthorized}
+
+      {:object, :error} ->
         {:ok, :unauthorized}
     end
   end

lib/vonbraun/activity_pub/handler/delete.ex

@@ -1,7 +1,7 @@
 defmodule Vonbraun.ActivityPub.Handler.Delete do
   @behaviour Vonbraun.ActivityPub.HandlerBehaviour
 
-  @verb "Delete"
+  @verb "https://www.w3.org/ns/activitystreams#Delete"
 
   def type, do: @verb
 

lib/vonbraun/activity_pub/handler/follow.ex

@@ -7,21 +7,23 @@ defmodule Vonbraun.ActivityPub.Handler.Follow do
   alias Vonbraun.ActivityPub.Object
   alias Vonbraun.Util
 
-  @verb "Follow"
+  @verb "https://www.w3.org/ns/activitystreams#Follow"
 
   def type, do: @verb
 
   def handle(
-        %{
-          "id" => activity_id,
-          "type" => @verb,
-          "actor" => follow_requester_id,
+        activity = %{
+          "actor" => actor_value,
           "object" => follow_target
         },
         actor = %{}
       )
-      when is_binary(follow_requester_id) and is_binary(follow_target) and is_binary(activity_id) do
-    with {:valid_target, true} <- {:valid_target, Util.my_id() == follow_target},
+      when is_binary(follow_target) do
+    my_id = Util.my_id()
+
+    with {:activity_id, {:ok, activity_id}} <- {:activity_id, Util.get_only_id(activity)},
+         {:actor_id, {:ok, follow_requester_id}} <- {:actor_id, Util.get_only_id(actor_value)},
+         {:valid_target, {:ok, ^my_id}} <- {:valid_target, Util.get_only_id(follow_target)},
          {:add, {:ok, %Actor{:blocked => nil, :follows_me_state => follows_me_state}}}
          when not is_nil(follows_me_state) <-
            {:add, Actor.maybe_add_follower(follow_requester_id)} do
@@ -66,7 +68,13 @@ defmodule Vonbraun.ActivityPub.Handler.Follow do
         {:ok, :ignored}
       end
     else
-      {:valid_target, false} ->
+      {:actor_id, :error} ->
+        {:ok, :unauthorized}
+
+      {:activity_id, :error} ->
+        {:ok, :unauthorized}
+
+      {:valid_target, _} ->
         {:ok, :unauthorized}
 
       {:add, {:ok, %Actor{:blocked => blocked_ts}}} when not is_nil(blocked_ts) ->

lib/vonbraun/activity_pub/handler/reject.ex

@@ -4,19 +4,24 @@ defmodule Vonbraun.ActivityPub.Handler.Reject do
   require Logger
   alias Vonbraun.Ecto.Schema.Actor
   alias Vonbraun.Util
-  import Vonbraun.ActivityPub.Handler.Accept, only: [extract_follow_object_actor: 1]
 
-  @verb "Reject"
+  import Vonbraun.ActivityPub.Handler.Accept,
+    only: [extract_follow_object_actor_id: 1]
+
+  @verb "https://www.w3.org/ns/activitystreams#Reject"
+
   def type, do: @verb
 
   # Lots of kinds of things can be rejected but for right now only follows.
   def handle(%{
-        "type" => @verb,
-        "actor" => actor_id,
-        "object" => object = %{"type" => "Follow"}
+        "actor" => actor_value,
+        "object" => object_value
       }) do
-    with {:actor, {:ok, follow_actor_id}} <- {:actor, extract_follow_object_actor(object)},
-         {:match, true} <- {:match, follow_actor_id == Util.my_id()},
+    my_id = Util.my_id()
+
+    with {:object, {:ok, object}} <- {:object, Util.get_only_property(object_value)},
+         {:actor, {:ok, ^my_id}} <- {:actor, extract_follow_object_actor_id(object)},
+         {:actor_id, {:ok, actor_id}} <- {:actor_id, Util.get_only_id(actor_value)},
          {:asked, {:ok, %Actor{:blocked => nil, :following_state => "accepted"}}} <-
            {:asked, Actor.mark_pending_follow(actor_id, "rejected", force: true)} do
       Logger.info("Now following: #{actor_id}")
@@ -30,7 +35,7 @@ defmodule Vonbraun.ActivityPub.Handler.Reject do
 
       {:asked, {:ok, %Actor{:blocked => nil, :following_state => following_state}}} ->
         Logger.error(
-          "Weird following state after received Accept: #{following_state} from actor: #{actor_id} this should not happen."
+          "Weird following state after received Accept: #{following_state} from actor: #{inspect(actor_value)} this should not happen."
         )
 
         {:error, :following_state}
@@ -38,7 +43,10 @@ defmodule Vonbraun.ActivityPub.Handler.Reject do
       {:actor, {:error, _error}} ->
         {:ok, :unauthorized}
 
-      {:match, false} ->
+      {:actor_id, :error} ->
+        {:ok, :unauthorized}
+
+      {:object, :error} ->
         {:ok, :unauthorized}
     end
   end

lib/vonbraun/activity_pub/handler/undo.ex

@@ -4,17 +4,20 @@ defmodule Vonbraun.ActivityPub.Handler.Undo do
   require Logger
   alias Vonbraun.Ecto.Schema.Actor
   alias Vonbraun.Util
-  import Vonbraun.ActivityPub.Handler.Accept, only: [extract_follow_object_actor: 1]
+  import Vonbraun.ActivityPub.Handler.Accept, only: [extract_follow_object_actor_id: 1]
 
-  @verb "Undo"
+  @verb "https://www.w3.org/ns/activitystreams#Undo"
 
   def type, do: @verb
 
   # Lots of different kinds of things can be undone.
 
-  def handle(%{"type" => @verb, "actor" => actor_id, "object" => object = %{"type" => "Follow"}}) do
-    with {:actor, {:ok, follow_actor_id}} <- {:actor, extract_follow_object_actor(object)},
-         {:match, true} <- {:match, follow_actor_id == Util.my_id()},
+  def handle(%{"actor" => actor_value, "object" => object_value}) do
+    my_id = Util.my_id()
+
+    with {:object, {:ok, object}} <- {:object, Util.get_only_property(object_value)},
+         {:actor, {:ok, ^my_id}} <- {:actor, extract_follow_object_actor_id(object)},
+         {:actor_id, {:ok, actor_id}} <- {:actor_id, Util.get_only_id(actor_value)},
          {:asked, {:ok, %Actor{:following_state => nil}}} <-
            {:asked, Actor.remove_follower(actor_id)} do
       {:ok, :removed_follower}
@@ -30,7 +33,7 @@ defmodule Vonbraun.ActivityPub.Handler.Undo do
     end
   end
 
-  def handle(%{"type" => @verb}, %{}) do
+  def handle(%{}, %{}) do
     {:ok, :unknown}
   end
 end

lib/vonbraun/util.ex

@@ -30,7 +30,7 @@ defmodule Vonbraun.Util do
   """
   def get_only_property([property]), do: {:ok, property}
 
-  def get_only_property(property) when is_list(property), do: {:error}
+  def get_only_property(property) when is_list(property), do: :error
 
   def get_only_property(property), do: {:ok, property}