Add object getting/fetching

lib/clacks/activitypub.ex

@@ -57,6 +57,19 @@ defmodule Clacks.ActivityPub do
     }
   end
 
+  @spec synthesized_create(object :: map()) :: map()
+  def synthesized_create(object) do
+    %{
+      "@context" => @context,
+      "type" => "Create",
+      "object" => object,
+      # Mastodon doesn't include 'actor' in notes
+      "actor" => object["actor"] || object["attributedTo"],
+      "to" => object["to"],
+      "cc" => object["cc"]
+    }
+  end
+
   @spec object_id(id :: String.t()) :: String.t()
   def object_id(id) do
     url = Application.get_env(:clacks, ClacksWeb.Endpoint)[:url]

lib/clacks/object.ex

@@ -1,6 +1,9 @@
 defmodule Clacks.Object do
+  require Logger
   use Ecto.Schema
   import Ecto.Changeset
+  alias Clacks.Repo
+  import Ecto.Query
 
   @type t() :: %__MODULE__{}
 
@@ -15,4 +18,61 @@ defmodule Clacks.Object do
     |> cast(attrs, [:data])
     |> validate_required([:data])
   end
+
+  @spec get_by_ap_id(
+          ap_id :: String.t(),
+          force_refetch :: boolean(),
+          synthesize_create :: boolean()
+        ) :: t() | nil
+  def get_by_ap_id(ap_id, force_refetch \\ false, synthesize_create \\ true)
+      when is_binary(ap_id) do
+    if force_refetch do
+      fetch(ap_id, synthesize_create)
+    else
+      get_cached_by_ap_id(ap_id) || fetch(ap_id, synthesize_create)
+    end
+  end
+
+  @spec get_cached_by_ap_id(ap_id :: String.t()) :: t() | nil
+  def get_cached_by_ap_id(ap_id) when is_binary(ap_id) do
+    Repo.one(from o in __MODULE__, where: fragment("?->>'id'", o.data) == ^ap_id)
+  end
+
+  @spec fetch(ap_id :: String.t(), synthesize_create :: boolean()) :: t() | nil
+  def fetch(ap_id, synthesize_create \\ true) when is_binary(ap_id) do
+    case Clacks.ActivityPub.Fetcher.fetch_object(ap_id) do
+      nil ->
+        nil
+
+      data ->
+        existing = get_cached_by_ap_id(data["id"])
+
+        changeset =
+          changeset(existing || %__MODULE__{}, %{
+            data: data
+          })
+
+        case Repo.insert_or_update(changeset) do
+          {:ok, object} ->
+            if synthesize_create do
+              create = Clacks.ActivityPub.synthesized_create(data)
+
+              changeset =
+                Clacks.Activity.changeset(%Clacks.Activity{}, %{
+                  data: create,
+                  local: false,
+                  actor: data["actor"]
+                })
+
+              {:ok, _create} = Repo.insert_or_update(changeset)
+            end
+
+            object
+
+          {:error, changeset} ->
+            Logger.error("Couldn't store remote object #{ap_id}: #{inspect(changeset)}")
+            nil
+        end
+    end
+  end
 end