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   1 # Pleroma: A lightweight social networking server
   2 # Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
   3 # SPDX-License-Identifier: AGPL-3.0-only
   4
   5 defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   6   @moduledoc """
   7   A module to handle coding from internal to wire ActivityPub and back.
   8   """
   9   alias Pleroma.Activity
  10   alias Pleroma.Object
  11   alias Pleroma.Object.Containment
  12   alias Pleroma.Repo
  13   alias Pleroma.User
  14   alias Pleroma.Web.ActivityPub.ActivityPub
  15   alias Pleroma.Web.ActivityPub.Utils
  16   alias Pleroma.Web.ActivityPub.Visibility
  17   alias Pleroma.Web.Federator
  18   alias Pleroma.Workers.TransmogrifierWorker
  19
  20   import Ecto.Query
  21
  22   require Logger
  23   require Pleroma.Constants
  24
  25   @doc """
  26   Modifies an incoming AP object (mastodon format) to our internal format.
  27   """
  28   def fix_object(object, options \\ []) do
  29     object
  30     |> strip_internal_fields
  31     |> fix_actor
  32     |> fix_url
  33     |> fix_attachments
  34     |> fix_context
  35     |> fix_in_reply_to(options)
  36     |> fix_emoji
  37     |> fix_tag
  38     |> fix_content_map
  39     |> fix_addressing
  40     |> fix_summary
  41     |> fix_type(options)
  42   end
  43
  44   def fix_summary(%{"summary" => nil} = object) do
  45     Map.put(object, "summary", "")
  46   end
  47
  48   def fix_summary(%{"summary" => _} = object) do
  49     # summary is present, nothing to do
  50     object
  51   end
  52
  53   def fix_summary(object), do: Map.put(object, "summary", "")
  54
  55   def fix_addressing_list(map, field) do
  56     cond do
  57       is_binary(map[field]) ->
  58         Map.put(map, field, [map[field]])
  59
  60       is_nil(map[field]) ->
  61         Map.put(map, field, [])
  62
  63       true ->
  64         map
  65     end
  66   end
  67
  68   def fix_explicit_addressing(
  69         %{"to" => to, "cc" => cc} = object,
  70         explicit_mentions,
  71         follower_collection
  72       ) do
  73     explicit_to = Enum.filter(to, fn x -> x in explicit_mentions end)
  74
  75     explicit_cc = Enum.filter(to, fn x -> x not in explicit_mentions end)
  76
  77     final_cc =
  78       (cc ++ explicit_cc)
  79       |> Enum.reject(fn x -> String.ends_with?(x, "/followers") and x != follower_collection end)
  80       |> Enum.uniq()
  81
  82     object
  83     |> Map.put("to", explicit_to)
  84     |> Map.put("cc", final_cc)
  85   end
  86
  87   def fix_explicit_addressing(object, _explicit_mentions, _followers_collection), do: object
  88
  89   # if directMessage flag is set to true, leave the addressing alone
  90   def fix_explicit_addressing(%{"directMessage" => true} = object), do: object
  91
  92   def fix_explicit_addressing(object) do
  93     explicit_mentions = Utils.determine_explicit_mentions(object)
  94
  95     %User{follower_address: follower_collection} =
  96       object
  97       |> Containment.get_actor()
  98       |> User.get_cached_by_ap_id()
  99
 100     explicit_mentions =
 101       explicit_mentions ++
 102         [
 103           Pleroma.Constants.as_public(),
 104           follower_collection
 105         ]
 106
 107     fix_explicit_addressing(object, explicit_mentions, follower_collection)
 108   end
 109
 110   # if as:Public is addressed, then make sure the followers collection is also addressed
 111   # so that the activities will be delivered to local users.
 112   def fix_implicit_addressing(%{"to" => to, "cc" => cc} = object, followers_collection) do
 113     recipients = to ++ cc
 114
 115     if followers_collection not in recipients do
 116       cond do
 117         Pleroma.Constants.as_public() in cc ->
 118           to = to ++ [followers_collection]
 119           Map.put(object, "to", to)
 120
 121         Pleroma.Constants.as_public() in to ->
 122           cc = cc ++ [followers_collection]
 123           Map.put(object, "cc", cc)
 124
 125         true ->
 126           object
 127       end
 128     else
 129       object
 130     end
 131   end
 132
 133   def fix_implicit_addressing(object, _), do: object
 134
 135   def fix_addressing(object) do
 136     {:ok, %User{} = user} = User.get_or_fetch_by_ap_id(object["actor"])
 137     followers_collection = User.ap_followers(user)
 138
 139     object
 140     |> fix_addressing_list("to")
 141     |> fix_addressing_list("cc")
 142     |> fix_addressing_list("bto")
 143     |> fix_addressing_list("bcc")
 144     |> fix_explicit_addressing()
 145     |> fix_implicit_addressing(followers_collection)
 146   end
 147
 148   def fix_actor(%{"attributedTo" => actor} = object) do
 149     Map.put(object, "actor", Containment.get_actor(%{"actor" => actor}))
 150   end
 151
 152   def fix_in_reply_to(object, options \\ [])
 153
 154   def fix_in_reply_to(%{"inReplyTo" => in_reply_to} = object, options)
 155       when not is_nil(in_reply_to) do
 156     in_reply_to_id = prepare_in_reply_to(in_reply_to)
 157     object = Map.put(object, "inReplyToAtomUri", in_reply_to_id)
 158
 159     if Federator.allowed_incoming_reply_depth?(options[:depth]) do
 160       with {:ok, replied_object} <- get_obj_helper(in_reply_to_id, options),
 161            %Activity{} = _ <- Activity.get_create_by_object_ap_id(replied_object.data["id"]) do
 162         object
 163         |> Map.put("inReplyTo", replied_object.data["id"])
 164         |> Map.put("inReplyToAtomUri", object["inReplyToAtomUri"] || in_reply_to_id)
 165         |> Map.put("conversation", replied_object.data["context"] || object["conversation"])
 166         |> Map.put("context", replied_object.data["context"] || object["conversation"])
 167       else
 168         e ->
 169           Logger.error("Couldn't fetch #{inspect(in_reply_to_id)}, error: #{inspect(e)}")
 170           object
 171       end
 172     else
 173       object
 174     end
 175   end
 176
 177   def fix_in_reply_to(object, _options), do: object
 178
 179   defp prepare_in_reply_to(in_reply_to) do
 180     cond do
 181       is_bitstring(in_reply_to) ->
 182         in_reply_to
 183
 184       is_map(in_reply_to) && is_bitstring(in_reply_to["id"]) ->
 185         in_reply_to["id"]
 186
 187       is_list(in_reply_to) && is_bitstring(Enum.at(in_reply_to, 0)) ->
 188         Enum.at(in_reply_to, 0)
 189
 190       true ->
 191         ""
 192     end
 193   end
 194
 195   def fix_context(object) do
 196     context = object["context"] || object["conversation"] || Utils.generate_context_id()
 197
 198     object
 199     |> Map.put("context", context)
 200     |> Map.put("conversation", context)
 201   end
 202
 203   def fix_attachments(%{"attachment" => attachment} = object) when is_list(attachment) do
 204     attachments =
 205       Enum.map(attachment, fn data ->
 206         media_type = data["mediaType"] || data["mimeType"]
 207         href = data["url"] || data["href"]
 208         url = [%{"type" => "Link", "mediaType" => media_type, "href" => href}]
 209
 210         data
 211         |> Map.put("mediaType", media_type)
 212         |> Map.put("url", url)
 213       end)
 214
 215     Map.put(object, "attachment", attachments)
 216   end
 217
 218   def fix_attachments(%{"attachment" => attachment} = object) when is_map(attachment) do
 219     object
 220     |> Map.put("attachment", [attachment])
 221     |> fix_attachments()
 222   end
 223
 224   def fix_attachments(object), do: object
 225
 226   def fix_url(%{"url" => url} = object) when is_map(url) do
 227     Map.put(object, "url", url["href"])
 228   end
 229
 230   def fix_url(%{"type" => "Video", "url" => url} = object) when is_list(url) do
 231     first_element = Enum.at(url, 0)
 232
 233     link_element = Enum.find(url, fn x -> is_map(x) and x["mimeType"] == "text/html" end)
 234
 235     object
 236     |> Map.put("attachment", [first_element])
 237     |> Map.put("url", link_element["href"])
 238   end
 239
 240   def fix_url(%{"type" => object_type, "url" => url} = object)
 241       when object_type != "Video" and is_list(url) do
 242     first_element = Enum.at(url, 0)
 243
 244     url_string =
 245       cond do
 246         is_bitstring(first_element) -> first_element
 247         is_map(first_element) -> first_element["href"] || ""
 248         true -> ""
 249       end
 250
 251     Map.put(object, "url", url_string)
 252   end
 253
 254   def fix_url(object), do: object
 255
 256   def fix_emoji(%{"tag" => tags} = object) when is_list(tags) do
 257     emoji =
 258       tags
 259       |> Enum.filter(fn data -> data["type"] == "Emoji" and data["icon"] end)
 260       |> Enum.reduce(%{}, fn data, mapping ->
 261         name = String.trim(data["name"], ":")
 262
 263         Map.put(mapping, name, data["icon"]["url"])
 264       end)
 265
 266     # we merge mastodon and pleroma emoji into a single mapping, to allow for both wire formats
 267     emoji = Map.merge(object["emoji"] || %{}, emoji)
 268
 269     Map.put(object, "emoji", emoji)
 270   end
 271
 272   def fix_emoji(%{"tag" => %{"type" => "Emoji"} = tag} = object) do
 273     name = String.trim(tag["name"], ":")
 274     emoji = %{name => tag["icon"]["url"]}
 275
 276     Map.put(object, "emoji", emoji)
 277   end
 278
 279   def fix_emoji(object), do: object
 280
 281   def fix_tag(%{"tag" => tag} = object) when is_list(tag) do
 282     tags =
 283       tag
 284       |> Enum.filter(fn data -> data["type"] == "Hashtag" and data["name"] end)
 285       |> Enum.map(fn data -> String.slice(data["name"], 1..-1) end)
 286
 287     Map.put(object, "tag", tag ++ tags)
 288   end
 289
 290   def fix_tag(%{"tag" => %{"type" => "Hashtag", "name" => hashtag} = tag} = object) do
 291     combined = [tag, String.slice(hashtag, 1..-1)]
 292
 293     Map.put(object, "tag", combined)
 294   end
 295
 296   def fix_tag(%{"tag" => %{} = tag} = object), do: Map.put(object, "tag", [tag])
 297
 298   def fix_tag(object), do: object
 299
 300   # content map usually only has one language so this will do for now.
 301   def fix_content_map(%{"contentMap" => content_map} = object) do
 302     content_groups = Map.to_list(content_map)
 303     {_, content} = Enum.at(content_groups, 0)
 304
 305     Map.put(object, "content", content)
 306   end
 307
 308   def fix_content_map(object), do: object
 309
 310   def fix_type(object, options \\ [])
 311
 312   def fix_type(%{"inReplyTo" => reply_id, "name" => _} = object, options)
 313       when is_binary(reply_id) do
 314     with true <- Federator.allowed_incoming_reply_depth?(options[:depth]),
 315          {:ok, %{data: %{"type" => "Question"} = _} = _} <- get_obj_helper(reply_id, options) do
 316       Map.put(object, "type", "Answer")
 317     else
 318       _ -> object
 319     end
 320   end
 321
 322   def fix_type(object, _), do: object
 323
 324   defp mastodon_follow_hack(%{"id" => id, "actor" => follower_id}, followed) do
 325     with true <- id =~ "follows",
 326          %User{local: true} = follower <- User.get_cached_by_ap_id(follower_id),
 327          %Activity{} = activity <- Utils.fetch_latest_follow(follower, followed) do
 328       {:ok, activity}
 329     else
 330       _ -> {:error, nil}
 331     end
 332   end
 333
 334   defp mastodon_follow_hack(_, _), do: {:error, nil}
 335
 336   defp get_follow_activity(follow_object, followed) do
 337     with object_id when not is_nil(object_id) <- Utils.get_ap_id(follow_object),
 338          {_, %Activity{} = activity} <- {:activity, Activity.get_by_ap_id(object_id)} do
 339       {:ok, activity}
 340     else
 341       # Can't find the activity. This might a Mastodon 2.3 "Accept"
 342       {:activity, nil} ->
 343         mastodon_follow_hack(follow_object, followed)
 344
 345       _ ->
 346         {:error, nil}
 347     end
 348   end
 349
 350   # Reduce the object list to find the reported user.
 351   defp get_reported(objects) do
 352     Enum.reduce_while(objects, nil, fn ap_id, _ ->
 353       with %User{} = user <- User.get_cached_by_ap_id(ap_id) do
 354         {:halt, user}
 355       else
 356         _ -> {:cont, nil}
 357       end
 358     end)
 359   end
 360
 361   def handle_incoming(data, options \\ [])
 362
 363   # Flag objects are placed ahead of the ID check because Mastodon 2.8 and earlier send them
 364   # with nil ID.
 365   def handle_incoming(%{"type" => "Flag", "object" => objects, "actor" => actor} = data, _options) do
 366     with context <- data["context"] || Utils.generate_context_id(),
 367          content <- data["content"] || "",
 368          %User{} = actor <- User.get_cached_by_ap_id(actor),
 369          # Reduce the object list to find the reported user.
 370          %User{} = account <- get_reported(objects),
 371          # Remove the reported user from the object list.
 372          statuses <- Enum.filter(objects, fn ap_id -> ap_id != account.ap_id end) do
 373       %{
 374         actor: actor,
 375         context: context,
 376         account: account,
 377         statuses: statuses,
 378         content: content,
 379         additional: %{"cc" => [account.ap_id]}
 380       }
 381       |> ActivityPub.flag()
 382     end
 383   end
 384
 385   # disallow objects with bogus IDs
 386   def handle_incoming(%{"id" => nil}, _options), do: :error
 387   def handle_incoming(%{"id" => ""}, _options), do: :error
 388   # length of https:// = 8, should validate better, but good enough for now.
 389   def handle_incoming(%{"id" => id}, _options) when not (is_binary(id) and length(id) > 8),
 390     do: :error
 391
 392   # TODO: validate those with a Ecto scheme
 393   # - tags
 394   # - emoji
 395   def handle_incoming(
 396         %{"type" => "Create", "object" => %{"type" => objtype} = object} = data,
 397         options
 398       )
 399       when objtype in ["Article", "Note", "Video", "Page", "Question", "Answer"] do
 400     actor = Containment.get_actor(data)
 401
 402     data =
 403       Map.put(data, "actor", actor)
 404       |> fix_addressing
 405
 406     with nil <- Activity.get_create_by_object_ap_id(object["id"]),
 407          {:ok, %User{} = user} <- User.get_or_fetch_by_ap_id(data["actor"]) do
 408       options = Keyword.put(options, :depth, (options[:depth] || 0) + 1)
 409       object = fix_object(data["object"], options)
 410
 411       params = %{
 412         to: data["to"],
 413         object: object,
 414         actor: user,
 415         context: object["conversation"],
 416         local: false,
 417         published: data["published"],
 418         additional:
 419           Map.take(data, [
 420             "cc",
 421             "directMessage",
 422             "id"
 423           ])
 424       }
 425
 426       ActivityPub.create(params)
 427     else
 428       %Activity{} = activity -> {:ok, activity}
 429       _e -> :error
 430     end
 431   end
 432
 433   def handle_incoming(
 434         %{"type" => "Listen", "object" => %{"type" => "Audio"} = object} = data,
 435         options
 436       ) do
 437     actor = Containment.get_actor(data)
 438
 439     data =
 440       Map.put(data, "actor", actor)
 441       |> fix_addressing
 442
 443     with {:ok, %User{} = user} <- User.get_or_fetch_by_ap_id(data["actor"]) do
 444       options = Keyword.put(options, :depth, (options[:depth] || 0) + 1)
 445       object = fix_object(object, options)
 446
 447       params = %{
 448         to: data["to"],
 449         object: object,
 450         actor: user,
 451         context: nil,
 452         local: false,
 453         published: data["published"],
 454         additional: Map.take(data, ["cc", "id"])
 455       }
 456
 457       ActivityPub.listen(params)
 458     else
 459       _e -> :error
 460     end
 461   end
 462
 463   def handle_incoming(
 464         %{"type" => "Follow", "object" => followed, "actor" => follower, "id" => id} = data,
 465         _options
 466       ) do
 467     with %User{local: true} = followed <-
 468            User.get_cached_by_ap_id(Containment.get_actor(%{"actor" => followed})),
 469          {:ok, %User{} = follower} <-
 470            User.get_or_fetch_by_ap_id(Containment.get_actor(%{"actor" => follower})),
 471          {:ok, activity} <- ActivityPub.follow(follower, followed, id, false) do
 472       with deny_follow_blocked <- Pleroma.Config.get([:user, :deny_follow_blocked]),
 473            {_, false} <- {:user_blocked, User.blocks?(followed, follower) && deny_follow_blocked},
 474            {_, false} <- {:user_locked, User.locked?(followed)},
 475            {_, {:ok, follower}} <- {:follow, User.follow(follower, followed)},
 476            {_, {:ok, _}} <-
 477              {:follow_state_update, Utils.update_follow_state_for_all(activity, "accept")} do
 478         ActivityPub.accept(%{
 479           to: [follower.ap_id],
 480           actor: followed,
 481           object: data,
 482           local: true
 483         })
 484       else
 485         {:user_blocked, true} ->
 486           {:ok, _} = Utils.update_follow_state_for_all(activity, "reject")
 487
 488           ActivityPub.reject(%{
 489             to: [follower.ap_id],
 490             actor: followed,
 491             object: data,
 492             local: true
 493           })
 494
 495         {:follow, {:error, _}} ->
 496           {:ok, _} = Utils.update_follow_state_for_all(activity, "reject")
 497
 498           ActivityPub.reject(%{
 499             to: [follower.ap_id],
 500             actor: followed,
 501             object: data,
 502             local: true
 503           })
 504
 505         {:user_locked, true} ->
 506           :noop
 507       end
 508
 509       {:ok, activity}
 510     else
 511       _e ->
 512         :error
 513     end
 514   end
 515
 516   def handle_incoming(
 517         %{"type" => "Accept", "object" => follow_object, "actor" => _actor, "id" => id} = data,
 518         _options
 519       ) do
 520     with actor <- Containment.get_actor(data),
 521          {:ok, %User{} = followed} <- User.get_or_fetch_by_ap_id(actor),
 522          {:ok, follow_activity} <- get_follow_activity(follow_object, followed),
 523          {:ok, follow_activity} <- Utils.update_follow_state_for_all(follow_activity, "accept"),
 524          %User{local: true} = follower <- User.get_cached_by_ap_id(follow_activity.data["actor"]),
 525          {:ok, _follower} = User.follow(follower, followed) do
 526       ActivityPub.accept(%{
 527         to: follow_activity.data["to"],
 528         type: "Accept",
 529         actor: followed,
 530         object: follow_activity.data["id"],
 531         local: false,
 532         activity_id: id
 533       })
 534     else
 535       _e -> :error
 536     end
 537   end
 538
 539   def handle_incoming(
 540         %{"type" => "Reject", "object" => follow_object, "actor" => _actor, "id" => id} = data,
 541         _options
 542       ) do
 543     with actor <- Containment.get_actor(data),
 544          {:ok, %User{} = followed} <- User.get_or_fetch_by_ap_id(actor),
 545          {:ok, follow_activity} <- get_follow_activity(follow_object, followed),
 546          {:ok, follow_activity} <- Utils.update_follow_state_for_all(follow_activity, "reject"),
 547          %User{local: true} = follower <- User.get_cached_by_ap_id(follow_activity.data["actor"]),
 548          {:ok, activity} <-
 549            ActivityPub.reject(%{
 550              to: follow_activity.data["to"],
 551              type: "Reject",
 552              actor: followed,
 553              object: follow_activity.data["id"],
 554              local: false,
 555              activity_id: id
 556            }) do
 557       User.unfollow(follower, followed)
 558
 559       {:ok, activity}
 560     else
 561       _e -> :error
 562     end
 563   end
 564
 565   def handle_incoming(
 566         %{"type" => "Like", "object" => object_id, "actor" => _actor, "id" => id} = data,
 567         _options
 568       ) do
 569     with actor <- Containment.get_actor(data),
 570          {:ok, %User{} = actor} <- User.get_or_fetch_by_ap_id(actor),
 571          {:ok, object} <- get_obj_helper(object_id),
 572          {:ok, activity, _object} <- ActivityPub.like(actor, object, id, false) do
 573       {:ok, activity}
 574     else
 575       _e -> :error
 576     end
 577   end
 578
 579   def handle_incoming(
 580         %{"type" => "Announce", "object" => object_id, "actor" => _actor, "id" => id} = data,
 581         _options
 582       ) do
 583     with actor <- Containment.get_actor(data),
 584          {:ok, %User{} = actor} <- User.get_or_fetch_by_ap_id(actor),
 585          {:ok, object} <- get_embedded_obj_helper(object_id, actor),
 586          public <- Visibility.is_public?(data),
 587          {:ok, activity, _object} <- ActivityPub.announce(actor, object, id, false, public) do
 588       {:ok, activity}
 589     else
 590       _e -> :error
 591     end
 592   end
 593
 594   def handle_incoming(
 595         %{"type" => "Update", "object" => %{"type" => object_type} = object, "actor" => actor_id} =
 596           data,
 597         _options
 598       )
 599       when object_type in [
 600              "Person",
 601              "Application",
 602              "Service",
 603              "Organization"
 604            ] do
 605     with %User{ap_id: ^actor_id} = actor <- User.get_cached_by_ap_id(object["id"]) do
 606       {:ok, new_user_data} = ActivityPub.user_data_from_user_object(object)
 607
 608       locked = new_user_data[:locked] || false
 609       attachment = get_in(new_user_data, [:source_data, "attachment"]) || []
 610       invisible = new_user_data[:invisible] || false
 611
 612       fields =
 613         attachment
 614         |> Enum.filter(fn %{"type" => t} -> t == "PropertyValue" end)
 615         |> Enum.map(fn fields -> Map.take(fields, ["name", "value"]) end)
 616
 617       update_data =
 618         new_user_data
 619         |> Map.take([:avatar, :banner, :bio, :name, :also_known_as])
 620         |> Map.put(:fields, fields)
 621         |> Map.put(:locked, locked)
 622         |> Map.put(:invisible, invisible)
 623
 624       actor
 625       |> User.upgrade_changeset(update_data, true)
 626       |> User.update_and_set_cache()
 627
 628       ActivityPub.update(%{
 629         local: false,
 630         to: data["to"] || [],
 631         cc: data["cc"] || [],
 632         object: object,
 633         actor: actor_id,
 634         activity_id: data["id"]
 635       })
 636     else
 637       e ->
 638         Logger.error(e)
 639         :error
 640     end
 641   end
 642
 643   # TODO: We presently assume that any actor on the same origin domain as the object being
 644   # deleted has the rights to delete that object.  A better way to validate whether or not
 645   # the object should be deleted is to refetch the object URI, which should return either
 646   # an error or a tombstone.  This would allow us to verify that a deletion actually took
 647   # place.
 648   def handle_incoming(
 649         %{"type" => "Delete", "object" => object_id, "actor" => actor, "id" => id} = data,
 650         _options
 651       ) do
 652     object_id = Utils.get_ap_id(object_id)
 653
 654     with actor <- Containment.get_actor(data),
 655          {:ok, %User{} = actor} <- User.get_or_fetch_by_ap_id(actor),
 656          {:ok, object} <- get_obj_helper(object_id),
 657          :ok <- Containment.contain_origin(actor.ap_id, object.data),
 658          {:ok, activity} <-
 659            ActivityPub.delete(object, local: false, activity_id: id, actor: actor.ap_id) do
 660       {:ok, activity}
 661     else
 662       nil ->
 663         case User.get_cached_by_ap_id(object_id) do
 664           %User{ap_id: ^actor} = user ->
 665             User.delete(user)
 666
 667           nil ->
 668             :error
 669         end
 670
 671       _e ->
 672         :error
 673     end
 674   end
 675
 676   def handle_incoming(
 677         %{
 678           "type" => "Undo",
 679           "object" => %{"type" => "Announce", "object" => object_id},
 680           "actor" => _actor,
 681           "id" => id
 682         } = data,
 683         _options
 684       ) do
 685     with actor <- Containment.get_actor(data),
 686          {:ok, %User{} = actor} <- User.get_or_fetch_by_ap_id(actor),
 687          {:ok, object} <- get_obj_helper(object_id),
 688          {:ok, activity, _} <- ActivityPub.unannounce(actor, object, id, false) do
 689       {:ok, activity}
 690     else
 691       _e -> :error
 692     end
 693   end
 694
 695   def handle_incoming(
 696         %{
 697           "type" => "Undo",
 698           "object" => %{"type" => "Follow", "object" => followed},
 699           "actor" => follower,
 700           "id" => id
 701         } = _data,
 702         _options
 703       ) do
 704     with %User{local: true} = followed <- User.get_cached_by_ap_id(followed),
 705          {:ok, %User{} = follower} <- User.get_or_fetch_by_ap_id(follower),
 706          {:ok, activity} <- ActivityPub.unfollow(follower, followed, id, false) do
 707       User.unfollow(follower, followed)
 708       {:ok, activity}
 709     else
 710       _e -> :error
 711     end
 712   end
 713
 714   def handle_incoming(
 715         %{
 716           "type" => "Undo",
 717           "object" => %{"type" => "Block", "object" => blocked},
 718           "actor" => blocker,
 719           "id" => id
 720         } = _data,
 721         _options
 722       ) do
 723     with %User{local: true} = blocked <- User.get_cached_by_ap_id(blocked),
 724          {:ok, %User{} = blocker} <- User.get_or_fetch_by_ap_id(blocker),
 725          {:ok, activity} <- ActivityPub.unblock(blocker, blocked, id, false) do
 726       User.unblock(blocker, blocked)
 727       {:ok, activity}
 728     else
 729       _e -> :error
 730     end
 731   end
 732
 733   def handle_incoming(
 734         %{"type" => "Block", "object" => blocked, "actor" => blocker, "id" => id} = _data,
 735         _options
 736       ) do
 737     with %User{local: true} = blocked = User.get_cached_by_ap_id(blocked),
 738          {:ok, %User{} = blocker} = User.get_or_fetch_by_ap_id(blocker),
 739          {:ok, activity} <- ActivityPub.block(blocker, blocked, id, false) do
 740       User.unfollow(blocker, blocked)
 741       User.block(blocker, blocked)
 742       {:ok, activity}
 743     else
 744       _e -> :error
 745     end
 746   end
 747
 748   def handle_incoming(
 749         %{
 750           "type" => "Undo",
 751           "object" => %{"type" => "Like", "object" => object_id},
 752           "actor" => _actor,
 753           "id" => id
 754         } = data,
 755         _options
 756       ) do
 757     with actor <- Containment.get_actor(data),
 758          {:ok, %User{} = actor} <- User.get_or_fetch_by_ap_id(actor),
 759          {:ok, object} <- get_obj_helper(object_id),
 760          {:ok, activity, _, _} <- ActivityPub.unlike(actor, object, id, false) do
 761       {:ok, activity}
 762     else
 763       _e -> :error
 764     end
 765   end
 766
 767   # For Undos that don't have the complete object attached, try to find it in our database.
 768   def handle_incoming(
 769         %{
 770           "type" => "Undo",
 771           "object" => object
 772         } = activity,
 773         options
 774       )
 775       when is_binary(object) do
 776     with %Activity{data: data} <- Activity.get_by_ap_id(object) do
 777       activity
 778       |> Map.put("object", data)
 779       |> handle_incoming(options)
 780     else
 781       _e -> :error
 782     end
 783   end
 784
 785   def handle_incoming(_, _), do: :error
 786
 787   @spec get_obj_helper(String.t(), Keyword.t()) :: {:ok, Object.t()} | nil
 788   def get_obj_helper(id, options \\ []) do
 789     case Object.normalize(id, true, options) do
 790       %Object{} = object -> {:ok, object}
 791       _ -> nil
 792     end
 793   end
 794
 795   @spec get_embedded_obj_helper(String.t() | Object.t(), User.t()) :: {:ok, Object.t()} | nil
 796   def get_embedded_obj_helper(%{"attributedTo" => attributed_to, "id" => object_id} = data, %User{
 797         ap_id: ap_id
 798       })
 799       when attributed_to == ap_id do
 800     with {:ok, activity} <-
 801            handle_incoming(%{
 802              "type" => "Create",
 803              "to" => data["to"],
 804              "cc" => data["cc"],
 805              "actor" => attributed_to,
 806              "object" => data
 807            }) do
 808       {:ok, Object.normalize(activity)}
 809     else
 810       _ -> get_obj_helper(object_id)
 811     end
 812   end
 813
 814   def get_embedded_obj_helper(object_id, _) do
 815     get_obj_helper(object_id)
 816   end
 817
 818   def set_reply_to_uri(%{"inReplyTo" => in_reply_to} = object) when is_binary(in_reply_to) do
 819     with false <- String.starts_with?(in_reply_to, "http"),
 820          {:ok, %{data: replied_to_object}} <- get_obj_helper(in_reply_to) do
 821       Map.put(object, "inReplyTo", replied_to_object["external_url"] || in_reply_to)
 822     else
 823       _e -> object
 824     end
 825   end
 826
 827   def set_reply_to_uri(obj), do: obj
 828
 829   # Prepares the object of an outgoing create activity.
 830   def prepare_object(object) do
 831     object
 832     |> set_sensitive
 833     |> add_hashtags
 834     |> add_mention_tags
 835     |> add_emoji_tags
 836     |> add_attributed_to
 837     |> prepare_attachments
 838     |> set_conversation
 839     |> set_reply_to_uri
 840     |> strip_internal_fields
 841     |> strip_internal_tags
 842     |> set_type
 843   end
 844
 845   #  @doc
 846   #  """
 847   #  internal -> Mastodon
 848   #  """
 849
 850   def prepare_outgoing(%{"type" => activity_type, "object" => object_id} = data)
 851       when activity_type in ["Create", "Listen"] do
 852     object =
 853       object_id
 854       |> Object.normalize()
 855       |> Map.get(:data)
 856       |> prepare_object
 857
 858     data =
 859       data
 860       |> Map.put("object", object)
 861       |> Map.merge(Utils.make_json_ld_header())
 862       |> Map.delete("bcc")
 863
 864     {:ok, data}
 865   end
 866
 867   def prepare_outgoing(%{"type" => "Announce", "actor" => ap_id, "object" => object_id} = data) do
 868     object =
 869       object_id
 870       |> Object.normalize()
 871
 872     data =
 873       if Visibility.is_private?(object) && object.data["actor"] == ap_id do
 874         data |> Map.put("object", object |> Map.get(:data) |> prepare_object)
 875       else
 876         data |> maybe_fix_object_url
 877       end
 878
 879     data =
 880       data
 881       |> strip_internal_fields
 882       |> Map.merge(Utils.make_json_ld_header())
 883       |> Map.delete("bcc")
 884
 885     {:ok, data}
 886   end
 887
 888   # Mastodon Accept/Reject requires a non-normalized object containing the actor URIs,
 889   # because of course it does.
 890   def prepare_outgoing(%{"type" => "Accept"} = data) do
 891     with follow_activity <- Activity.normalize(data["object"]) do
 892       object = %{
 893         "actor" => follow_activity.actor,
 894         "object" => follow_activity.data["object"],
 895         "id" => follow_activity.data["id"],
 896         "type" => "Follow"
 897       }
 898
 899       data =
 900         data
 901         |> Map.put("object", object)
 902         |> Map.merge(Utils.make_json_ld_header())
 903
 904       {:ok, data}
 905     end
 906   end
 907
 908   def prepare_outgoing(%{"type" => "Reject"} = data) do
 909     with follow_activity <- Activity.normalize(data["object"]) do
 910       object = %{
 911         "actor" => follow_activity.actor,
 912         "object" => follow_activity.data["object"],
 913         "id" => follow_activity.data["id"],
 914         "type" => "Follow"
 915       }
 916
 917       data =
 918         data
 919         |> Map.put("object", object)
 920         |> Map.merge(Utils.make_json_ld_header())
 921
 922       {:ok, data}
 923     end
 924   end
 925
 926   def prepare_outgoing(%{"type" => _type} = data) do
 927     data =
 928       data
 929       |> strip_internal_fields
 930       |> maybe_fix_object_url
 931       |> Map.merge(Utils.make_json_ld_header())
 932
 933     {:ok, data}
 934   end
 935
 936   def maybe_fix_object_url(%{"object" => object} = data) when is_binary(object) do
 937     with false <- String.starts_with?(object, "http"),
 938          {:fetch, {:ok, relative_object}} <- {:fetch, get_obj_helper(object)},
 939          %{data: %{"external_url" => external_url}} when not is_nil(external_url) <-
 940            relative_object do
 941       Map.put(data, "object", external_url)
 942     else
 943       {:fetch, e} ->
 944         Logger.error("Couldn't fetch #{object} #{inspect(e)}")
 945         data
 946
 947       _ ->
 948         data
 949     end
 950   end
 951
 952   def maybe_fix_object_url(data), do: data
 953
 954   def add_hashtags(object) do
 955     tags =
 956       (object["tag"] || [])
 957       |> Enum.map(fn
 958         # Expand internal representation tags into AS2 tags.
 959         tag when is_binary(tag) ->
 960           %{
 961             "href" => Pleroma.Web.Endpoint.url() <> "/tags/#{tag}",
 962             "name" => "##{tag}",
 963             "type" => "Hashtag"
 964           }
 965
 966         # Do not process tags which are already AS2 tag objects.
 967         tag when is_map(tag) ->
 968           tag
 969       end)
 970
 971     Map.put(object, "tag", tags)
 972   end
 973
 974   def add_mention_tags(object) do
 975     mentions =
 976       object
 977       |> Utils.get_notified_from_object()
 978       |> Enum.map(&build_mention_tag/1)
 979
 980     tags = object["tag"] || []
 981
 982     Map.put(object, "tag", tags ++ mentions)
 983   end
 984
 985   defp build_mention_tag(%{ap_id: ap_id, nickname: nickname} = _) do
 986     %{"type" => "Mention", "href" => ap_id, "name" => "@#{nickname}"}
 987   end
 988
 989   def take_emoji_tags(%User{emoji: emoji}) do
 990     emoji
 991     |> Enum.flat_map(&Map.to_list/1)
 992     |> Enum.map(&build_emoji_tag/1)
 993   end
 994
 995   # TODO: we should probably send mtime instead of unix epoch time for updated
 996   def add_emoji_tags(%{"emoji" => emoji} = object) do
 997     tags = object["tag"] || []
 998
 999     out = Enum.map(emoji, &build_emoji_tag/1)
1000
1001     Map.put(object, "tag", tags ++ out)
1002   end
1003
1004   def add_emoji_tags(object), do: object
1005
1006   defp build_emoji_tag({name, url}) do
1007     %{
1008       "icon" => %{"url" => url, "type" => "Image"},
1009       "name" => ":" <> name <> ":",
1010       "type" => "Emoji",
1011       "updated" => "1970-01-01T00:00:00Z",
1012       "id" => url
1013     }
1014   end
1015
1016   def set_conversation(object) do
1017     Map.put(object, "conversation", object["context"])
1018   end
1019
1020   def set_sensitive(object) do
1021     tags = object["tag"] || []
1022     Map.put(object, "sensitive", "nsfw" in tags)
1023   end
1024
1025   def set_type(%{"type" => "Answer"} = object) do
1026     Map.put(object, "type", "Note")
1027   end
1028
1029   def set_type(object), do: object
1030
1031   def add_attributed_to(object) do
1032     attributed_to = object["attributedTo"] || object["actor"]
1033     Map.put(object, "attributedTo", attributed_to)
1034   end
1035
1036   def prepare_attachments(object) do
1037     attachments =
1038       (object["attachment"] || [])
1039       |> Enum.map(fn data ->
1040         [%{"mediaType" => media_type, "href" => href} | _] = data["url"]
1041         %{"url" => href, "mediaType" => media_type, "name" => data["name"], "type" => "Document"}
1042       end)
1043
1044     Map.put(object, "attachment", attachments)
1045   end
1046
1047   defp strip_internal_fields(object) do
1048     object
1049     |> Map.drop(Pleroma.Constants.object_internal_fields())
1050   end
1051
1052   defp strip_internal_tags(%{"tag" => tags} = object) do
1053     tags = Enum.filter(tags, fn x -> is_map(x) end)
1054
1055     Map.put(object, "tag", tags)
1056   end
1057
1058   defp strip_internal_tags(object), do: object
1059
1060   def perform(:user_upgrade, user) do
1061     # we pass a fake user so that the followers collection is stripped away
1062     old_follower_address = User.ap_followers(%User{nickname: user.nickname})
1063
1064     q =
1065       from(
1066         u in User,
1067         where: ^old_follower_address in u.following,
1068         update: [
1069           set: [
1070             following:
1071               fragment(
1072                 "array_replace(?,?,?)",
1073                 u.following,
1074                 ^old_follower_address,
1075                 ^user.follower_address
1076               )
1077           ]
1078         ]
1079       )
1080
1081     Repo.update_all(q, [])
1082
1083     q =
1084       from(
1085         a in Activity,
1086         where: ^old_follower_address in a.recipients,
1087         update: [
1088           set: [
1089             recipients:
1090               fragment(
1091                 "array_replace(?,?,?)",
1092                 a.recipients,
1093                 ^old_follower_address,
1094                 ^user.follower_address
1095               )
1096           ]
1097         ]
1098       )
1099
1100     Repo.update_all(q, [])
1101   end
1102
1103   def upgrade_user_from_ap_id(ap_id) do
1104     with %User{local: false} = user <- User.get_cached_by_ap_id(ap_id),
1105          {:ok, data} <- ActivityPub.fetch_and_prepare_user_from_ap_id(ap_id),
1106          already_ap <- User.ap_enabled?(user),
1107          {:ok, user} <- upgrade_user(user, data) do
1108       if not already_ap do
1109         TransmogrifierWorker.enqueue("user_upgrade", %{"user_id" => user.id})
1110       end
1111
1112       {:ok, user}
1113     else
1114       %User{} = user -> {:ok, user}
1115       e -> e
1116     end
1117   end
1118
1119   defp upgrade_user(user, data) do
1120     user
1121     |> User.upgrade_changeset(data, true)
1122     |> User.update_and_set_cache()
1123   end
1124
1125   def maybe_fix_user_url(%{"url" => url} = data) when is_map(url) do
1126     Map.put(data, "url", url["href"])
1127   end
1128
1129   def maybe_fix_user_url(data), do: data
1130
1131   def maybe_fix_user_object(data), do: maybe_fix_user_url(data)
1132 end