ObjectValidator: Basic `Block` support.

lib/pleroma/web/activity_pub/builder.ex

@@ -138,6 +138,18 @@ def update(actor, object) do
      }, []}
   end
 
+  @spec block(User.t(), User.t()) :: {:ok, map(), keyword()}
+  def block(blocker, blocked) do
+    {:ok,
+     %{
+       "id" => Utils.generate_activity_id(),
+       "type" => "Block",
+       "actor" => blocker.ap_id,
+       "object" => blocked.ap_id,
+       "to" => [blocked.ap_id]
+     }, []}
+  end
+
   @spec announce(User.t(), Object.t(), keyword()) :: {:ok, map(), keyword()}
   def announce(actor, object, options \\ []) do
     public? = Keyword.get(options, :public, false)

lib/pleroma/web/activity_pub/object_validator.ex

@@ -13,6 +13,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
   alias Pleroma.Object
   alias Pleroma.User
   alias Pleroma.Web.ActivityPub.ObjectValidators.AnnounceValidator
+  alias Pleroma.Web.ActivityPub.ObjectValidators.BlockValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.ChatMessageValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.CreateChatMessageValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.DeleteValidator
@@ -24,6 +25,16 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
   @spec validate(map(), keyword()) :: {:ok, map(), keyword()} | {:error, any()}
   def validate(object, meta)
 
+  def validate(%{"type" => "Block"} = block_activity, meta) do
+    with {:ok, block_activity} <-
+           block_activity
+           |> BlockValidator.cast_and_validate()
+           |> Ecto.Changeset.apply_action(:insert) do
+      block_activity = stringify_keys(block_activity)
+      {:ok, block_activity, meta}
+    end
+  end
+
   def validate(%{"type" => "Update"} = update_activity, meta) do
     with {:ok, update_activity} <-
            update_activity

lib/pleroma/web/activity_pub/object_validators/block_validator.ex

@@ -0,0 +1,42 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.ObjectValidators.BlockValidator do
+  use Ecto.Schema
+
+  alias Pleroma.EctoType.ActivityPub.ObjectValidators
+
+  import Ecto.Changeset
+  import Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations
+
+  @primary_key false
+
+  embedded_schema do
+    field(:id, ObjectValidators.ObjectID, primary_key: true)
+    field(:type, :string)
+    field(:actor, ObjectValidators.ObjectID)
+    field(:to, ObjectValidators.Recipients, default: [])
+    field(:cc, ObjectValidators.Recipients, default: [])
+    field(:object, ObjectValidators.ObjectID)
+  end
+
+  def cast_data(data) do
+    %__MODULE__{}
+    |> cast(data, __schema__(:fields))
+  end
+
+  def validate_data(cng) do
+    cng
+    |> validate_required([:id, :type, :actor, :to, :cc, :object])
+    |> validate_inclusion(:type, ["Block"])
+    |> validate_actor_presence()
+    |> validate_actor_presence(field_name: :object)
+  end
+
+  def cast_and_validate(data) do
+    data
+    |> cast_data
+    |> validate_data
+  end
+end

test/web/activity_pub/object_validator_test.exs

@@ -654,4 +654,31 @@ test "returns an error if the object can't be updated by the actor", %{
       assert {:error, _cng} = ObjectValidator.validate(update, [])
     end
   end
+
+  describe "blocks" do
+    setup do
+      user = insert(:user)
+      blocked = insert(:user)
+
+      {:ok, valid_block, []} = Builder.block(user, blocked)
+
+      %{user: user, valid_block: valid_block}
+    end
+
+    test "validates a basic object", %{
+      valid_block: valid_block
+    } do
+      assert {:ok, _block, []} = ObjectValidator.validate(valid_block, [])
+    end
+
+    test "returns an error if we don't know the blocked user", %{
+      valid_block: valid_block
+    } do
+      block =
+        valid_block
+        |> Map.put("object", "https://gensokyo.2hu/users/raymoo")
+
+      assert {:error, _cng} = ObjectValidator.validate(block, [])
+    end
+  end
 end