defmodule Mobilizon.Federation.ActivityStream.Converter.Post do @moduledoc """ Post converter. This module allows to convert posts from ActivityStream format to our own internal one, and back. """ alias Mobilizon.Actors.Actor alias Mobilizon.Federation.ActivityPub.Actor, as: ActivityPubActor alias Mobilizon.Federation.ActivityPub.{Audience, Utils} alias Mobilizon.Federation.ActivityStream.{Converter, Convertible} alias Mobilizon.Federation.ActivityStream.Converter.Media, as: MediaConverter alias Mobilizon.Posts.Post require Logger import Mobilizon.Federation.ActivityStream.Converter.Utils, only: [ process_pictures: 2 ] @behaviour Converter defimpl Convertible, for: Post do alias Mobilizon.Federation.ActivityStream.Converter.Post, as: PostConverter defdelegate model_to_as(post), to: PostConverter end @banner_picture_name "Banner" @doc """ Convert an post struct to an ActivityStream representation """ @impl Converter @spec model_to_as(Post.t()) :: map def model_to_as( %Post{ author: %Actor{url: actor_url}, attributed_to: %Actor{ url: creator_url } } = post ) do audience = Audience.calculate_to_and_cc_from_mentions(post) %{ "type" => "Article", "actor" => actor_url, "id" => post.url, "name" => post.title, "content" => post.body, "attributedTo" => creator_url, "published" => (post.publish_at || post.inserted_at) |> to_date(), "attachment" => [], "draft" => post.draft } |> Map.merge(audience) |> maybe_add_post_picture(post) |> maybe_add_inline_media(post) end @doc """ Converts an AP object data to our internal data structure. """ @impl Converter @spec as_to_model_data(map) :: {:ok, map} | {:error, any()} def as_to_model_data( %{"type" => "Article", "actor" => creator, "attributedTo" => group_uri} = object ) do with {:ok, %Actor{id: attributed_to_id} = group} <- get_actor(group_uri), {:ok, %Actor{id: author_id}} <- get_actor(creator), {:visibility, visibility} <- {:visibility, get_visibility(object, group)}, [description: description, picture_id: picture_id, medias: medias] <- process_pictures(object, attributed_to_id) do %{ title: object["name"], body: description, url: object["id"], attributed_to_id: attributed_to_id, author_id: author_id, local: false, publish_at: object["published"], picture_id: picture_id, medias: medias, visibility: visibility, draft: object["draft"] == true } else {:error, err} -> {:error, err} err -> {:error, err} end end @spec get_actor(String.t() | map() | nil) :: {:ok, Actor.t()} | {:error, String.t()} defp get_actor(nil), do: {:error, "nil property found for actor data"} defp get_actor(actor), do: actor |> Utils.get_url() |> ActivityPubActor.get_or_fetch_actor_by_url() defp to_date(nil), do: nil defp to_date(%DateTime{} = date), do: DateTime.to_iso8601(date) defp to_date(%NaiveDateTime{} = date), do: NaiveDateTime.to_iso8601(date) @spec maybe_add_post_picture(map(), Post.t()) :: map() defp maybe_add_post_picture(res, post) do if is_nil(post.picture), do: res, else: Map.update( res, "attachment", [], &(&1 ++ [ post.picture |> MediaConverter.model_to_as() |> Map.put("name", @banner_picture_name) ]) ) end @spec maybe_add_inline_media(map(), Post.t()) :: map() defp maybe_add_inline_media(res, post) do medias = Enum.map(post.media, &MediaConverter.model_to_as/1) Map.update( res, "attachment", [], &(&1 ++ medias) ) end @ap_public "https://www.w3.org/ns/activitystreams#Public" defp get_visibility(%{"to" => to}, %Actor{ followers_url: followers_url, members_url: members_url }) do cond do @ap_public in to -> :public followers_url in to -> :unlisted members_url in to -> :private end end end