Merge branch 'tusooa/2775-emoji-policy' into 'develop'

EmojiPolicy

Closes #2775

See merge request pleroma/pleroma!3842

changelog.d/emoji-policy.add

@@ -0,0 +1 @@
+Implement MRF policy to reject or delist according to emojis

config/config.exs

@@ -408,6 +408,12 @@ config :pleroma, :mrf_keyword,
   federated_timeline_removal: [],
   replace: []
 
+config :pleroma, :mrf_emoji,
+  remove_url: [],
+  remove_shortcode: [],
+  federated_timeline_removal_url: [],
+  federated_timeline_removal_shortcode: []
+
 config :pleroma, :mrf_hashtag,
   sensitive: ["nsfw"],
   reject: [],

docs/configuration/cheatsheet.md

@@ -261,6 +261,11 @@ Notes:
 
 * `follower_nickname`: The name of the bot account to use for following newly discovered users. Using `followbot` or similar is strongly suggested.
 
+#### :mrf_emoji
+* `remove_url`: A list of patterns which result in emoji whose URL matches being removed from the message. This will apply to statuses, emoji reactions, and user profiles. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
+* `remove_shortcode`: A list of patterns which result in emoji whose shortcode matches being removed from the message. This will apply to statuses, emoji reactions, and user profiles. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
+* `federated_timeline_removal_url`: A list of patterns which result in message with emojis whose URLs match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
+* `federated_timeline_removal_shortcode`: A list of patterns which result in message with emojis whose shortcodes match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses. Each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html).
 
 ### :activitypub
 * `unfollow_blocked`: Whether blocks result in people getting unfollowed

lib/pleroma/constants.ex

@@ -42,6 +42,18 @@ defmodule Pleroma.Constants do
     ]
   )
 
+  const(status_object_types,
+    do: [
+      "Note",
+      "Question",
+      "Audio",
+      "Video",
+      "Event",
+      "Article",
+      "Page"
+    ]
+  )
+
   const(updatable_object_types,
     do: [
       "Note",

lib/pleroma/web/activity_pub/mrf/emoji_policy.ex

@@ -0,0 +1,281 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicy do
+  require Pleroma.Constants
+
+  alias Pleroma.Object.Updater
+  alias Pleroma.Web.ActivityPub.MRF.Utils
+
+  @moduledoc "Reject or force-unlisted emojis with certain URLs or names"
+
+  @behaviour Pleroma.Web.ActivityPub.MRF.Policy
+
+  defp config_remove_url do
+    Pleroma.Config.get([:mrf_emoji, :remove_url], [])
+  end
+
+  defp config_remove_shortcode do
+    Pleroma.Config.get([:mrf_emoji, :remove_shortcode], [])
+  end
+
+  defp config_unlist_url do
+    Pleroma.Config.get([:mrf_emoji, :federated_timeline_removal_url], [])
+  end
+
+  defp config_unlist_shortcode do
+    Pleroma.Config.get([:mrf_emoji, :federated_timeline_removal_shortcode], [])
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def history_awareness, do: :manual
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def filter(%{"type" => type, "object" => %{"type" => objtype} = object} = message)
+      when type in ["Create", "Update"] and objtype in Pleroma.Constants.status_object_types() do
+    with {:ok, object} <-
+           Updater.do_with_history(object, fn object ->
+             {:ok, process_remove(object, :url, config_remove_url())}
+           end),
+         {:ok, object} <-
+           Updater.do_with_history(object, fn object ->
+             {:ok, process_remove(object, :shortcode, config_remove_shortcode())}
+           end),
+         activity <- Map.put(message, "object", object),
+         activity <- maybe_delist(activity) do
+      {:ok, activity}
+    end
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def filter(%{"type" => type} = object) when type in Pleroma.Constants.actor_types() do
+    with object <- process_remove(object, :url, config_remove_url()),
+         object <- process_remove(object, :shortcode, config_remove_shortcode()) do
+      {:ok, object}
+    end
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def filter(%{"type" => "EmojiReact"} = object) do
+    with {:ok, _} <-
+           matched_emoji_checker(config_remove_url(), config_remove_shortcode()).(object) do
+      {:ok, object}
+    else
+      _ ->
+        {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"}
+    end
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def filter(message) do
+    {:ok, message}
+  end
+
+  defp match_string?(string, pattern) when is_binary(pattern) do
+    string == pattern
+  end
+
+  defp match_string?(string, %Regex{} = pattern) do
+    String.match?(string, pattern)
+  end
+
+  defp match_any?(string, patterns) do
+    Enum.any?(patterns, &match_string?(string, &1))
+  end
+
+  defp url_from_tag(%{"icon" => %{"url" => url}}), do: url
+  defp url_from_tag(_), do: nil
+
+  defp url_from_emoji({_name, url}), do: url
+
+  defp shortcode_from_tag(%{"name" => name}) when is_binary(name), do: String.trim(name, ":")
+  defp shortcode_from_tag(_), do: nil
+
+  defp shortcode_from_emoji({name, _url}), do: name
+
+  defp process_remove(object, :url, patterns) do
+    process_remove_impl(object, &url_from_tag/1, &url_from_emoji/1, patterns)
+  end
+
+  defp process_remove(object, :shortcode, patterns) do
+    process_remove_impl(object, &shortcode_from_tag/1, &shortcode_from_emoji/1, patterns)
+  end
+
+  defp process_remove_impl(object, extract_from_tag, extract_from_emoji, patterns) do
+    object =
+      if object["tag"] do
+        Map.put(
+          object,
+          "tag",
+          Enum.filter(
+            object["tag"],
+            fn
+              %{"type" => "Emoji"} = tag ->
+                str = extract_from_tag.(tag)
+
+                if is_binary(str) do
+                  not match_any?(str, patterns)
+                else
+                  true
+                end
+
+              _ ->
+                true
+            end
+          )
+        )
+      else
+        object
+      end
+
+    object =
+      if object["emoji"] do
+        Map.put(
+          object,
+          "emoji",
+          object["emoji"]
+          |> Enum.reduce(%{}, fn {name, url} = emoji, acc ->
+            if not match_any?(extract_from_emoji.(emoji), patterns) do
+              Map.put(acc, name, url)
+            else
+              acc
+            end
+          end)
+        )
+      else
+        object
+      end
+
+    object
+  end
+
+  defp matched_emoji_checker(urls, shortcodes) do
+    fn object ->
+      if any_emoji_match?(object, &url_from_tag/1, &url_from_emoji/1, urls) or
+           any_emoji_match?(
+             object,
+             &shortcode_from_tag/1,
+             &shortcode_from_emoji/1,
+             shortcodes
+           ) do
+        {:matched, nil}
+      else
+        {:ok, %{}}
+      end
+    end
+  end
+
+  defp maybe_delist(%{"object" => object, "to" => to, "type" => "Create"} = activity) do
+    check = matched_emoji_checker(config_unlist_url(), config_unlist_shortcode())
+
+    should_delist? = fn object ->
+      with {:ok, _} <- Pleroma.Object.Updater.do_with_history(object, check) do
+        false
+      else
+        _ -> true
+      end
+    end
+
+    if Pleroma.Constants.as_public() in to and should_delist?.(object) do
+      to = List.delete(to, Pleroma.Constants.as_public())
+      cc = [Pleroma.Constants.as_public() | activity["cc"] || []]
+
+      activity
+      |> Map.put("to", to)
+      |> Map.put("cc", cc)
+    else
+      activity
+    end
+  end
+
+  defp maybe_delist(activity), do: activity
+
+  defp any_emoji_match?(object, extract_from_tag, extract_from_emoji, patterns) do
+    Kernel.||(
+      Enum.any?(
+        object["tag"] || [],
+        fn
+          %{"type" => "Emoji"} = tag ->
+            str = extract_from_tag.(tag)
+
+            if is_binary(str) do
+              match_any?(str, patterns)
+            else
+              false
+            end
+
+          _ ->
+            false
+        end
+      ),
+      (object["emoji"] || [])
+      |> Enum.any?(fn emoji -> match_any?(extract_from_emoji.(emoji), patterns) end)
+    )
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def describe do
+    mrf_emoji =
+      Pleroma.Config.get(:mrf_emoji, [])
+      |> Enum.map(fn {key, value} ->
+        {key, Enum.map(value, &Utils.describe_regex_or_string/1)}
+      end)
+      |> Enum.into(%{})
+
+    {:ok, %{mrf_emoji: mrf_emoji}}
+  end
+
+  @impl Pleroma.Web.ActivityPub.MRF.Policy
+  def config_description do
+    %{
+      key: :mrf_emoji,
+      related_policy: "Pleroma.Web.ActivityPub.MRF.EmojiPolicy",
+      label: "MRF Emoji",
+      description:
+        "Reject or force-unlisted emojis whose URLs or names match a keyword or [Regex](https://hexdocs.pm/elixir/Regex.html).",
+      children: [
+        %{
+          key: :remove_url,
+          type: {:list, :string},
+          description: """
+            A list of patterns which result in emoji whose URL matches being removed from the message. This will apply to statuses, emoji reactions, and user profiles.
+
+            Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
+          """,
+          suggestions: ["https://example.org/foo.png", ~r/example.org\/foo/iu]
+        },
+        %{
+          key: :remove_shortcode,
+          type: {:list, :string},
+          description: """
+            A list of patterns which result in emoji whose shortcode matches being removed from the message. This will apply to statuses, emoji reactions, and user profiles.
+
+            Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
+          """,
+          suggestions: ["foo", ~r/foo/iu]
+        },
+        %{
+          key: :federated_timeline_removal_url,
+          type: {:list, :string},
+          description: """
+            A list of patterns which result in message with emojis whose URLs match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses.
+
+            Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
+          """,
+          suggestions: ["https://example.org/foo.png", ~r/example.org\/foo/iu]
+        },
+        %{
+          key: :federated_timeline_removal_shortcode,
+          type: {:list, :string},
+          description: """
+            A list of patterns which result in message with emojis whose shortcodes match being removed from federated timelines (a.k.a unlisted). This will apply only to statuses.
+
+            Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
+          """,
+          suggestions: ["foo", ~r/foo/iu]
+        }
+      ]
+    }
+  end
+end

lib/pleroma/web/activity_pub/mrf/keyword_policy.ex

@@ -5,6 +5,8 @@
 defmodule Pleroma.Web.ActivityPub.MRF.KeywordPolicy do
   require Pleroma.Constants
 
+  alias Pleroma.Web.ActivityPub.MRF.Utils
+
   @moduledoc "Reject or Word-Replace messages with a keyword or regex"
 
   @behaviour Pleroma.Web.ActivityPub.MRF.Policy
@@ -128,7 +130,6 @@ defmodule Pleroma.Web.ActivityPub.MRF.KeywordPolicy do
 
   @impl true
   def describe do
-    # This horror is needed to convert regex sigils to strings
     mrf_keyword =
       Pleroma.Config.get(:mrf_keyword, [])
       |> Enum.map(fn {key, value} ->
@@ -136,21 +137,12 @@ defmodule Pleroma.Web.ActivityPub.MRF.KeywordPolicy do
          Enum.map(value, fn
            {pattern, replacement} ->
              %{
-               "pattern" =>
-                 if not is_binary(pattern) do
-                   inspect(pattern)
-                 else
-                   pattern
-                 end,
+               "pattern" => Utils.describe_regex_or_string(pattern),
                "replacement" => replacement
              }
 
            pattern ->
-             if not is_binary(pattern) do
-               inspect(pattern)
-             else
-               pattern
-             end
+             Utils.describe_regex_or_string(pattern)
          end)}
       end)
       |> Enum.into(%{})

lib/pleroma/web/activity_pub/mrf/utils.ex

@@ -0,0 +1,15 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.Utils do
+  @spec describe_regex_or_string(String.t() | Regex.t()) :: String.t()
+  def describe_regex_or_string(pattern) do
+    # This horror is needed to convert regex sigils to strings
+    if not is_binary(pattern) do
+      inspect(pattern)
+    else
+      pattern
+    end
+  end
+end

test/pleroma/web/activity_pub/mrf/emoji_policy_test.exs

@@ -0,0 +1,425 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.EmojiPolicyTest do
+  use Pleroma.DataCase
+
+  require Pleroma.Constants
+
+  alias Pleroma.Web.ActivityPub.MRF
+  alias Pleroma.Web.ActivityPub.MRF.EmojiPolicy
+
+  setup do: clear_config(:mrf_emoji)
+
+  setup do
+    clear_config([:mrf_emoji], %{
+      remove_url: [],
+      remove_shortcode: [],
+      federated_timeline_removal_url: [],
+      federated_timeline_removal_shortcode: []
+    })
+  end
+
+  @emoji_tags [
+    %{
+      "icon" => %{
+        "type" => "Image",
+        "url" => "https://example.org/emoji/biribiri/mikoto_smile2.png"
+      },
+      "id" => "https://example.org/emoji/biribiri/mikoto_smile2.png",
+      "name" => ":mikoto_smile2:",
+      "type" => "Emoji",
+      "updated" => "1970-01-01T00:00:00Z"
+    },
+    %{
+      "icon" => %{
+        "type" => "Image",
+        "url" => "https://example.org/emoji/biribiri/mikoto_smile3.png"
+      },
+      "id" => "https://example.org/emoji/biribiri/mikoto_smile3.png",
+      "name" => ":mikoto_smile3:",
+      "type" => "Emoji",
+      "updated" => "1970-01-01T00:00:00Z"
+    },
+    %{
+      "icon" => %{
+        "type" => "Image",
+        "url" => "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      },
+      "id" => "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png",
+      "name" => ":nekomimi_girl_emoji_007:",
+      "type" => "Emoji",
+      "updated" => "1970-01-01T00:00:00Z"
+    },
+    %{
+      "icon" => %{
+        "type" => "Image",
+        "url" => "https://example.org/test.png"
+      },
+      "id" => "https://example.org/test.png",
+      "name" => ":test:",
+      "type" => "Emoji",
+      "updated" => "1970-01-01T00:00:00Z"
+    }
+  ]
+
+  @misc_tags [%{"type" => "Placeholder"}]
+
+  @user_data %{
+    "type" => "Person",
+    "id" => "https://example.org/placeholder",
+    "name" => "lol",
+    "tag" => @emoji_tags ++ @misc_tags
+  }
+
+  @status_data %{
+    "type" => "Create",
+    "object" => %{
+      "type" => "Note",
+      "id" => "https://example.org/placeholder",
+      "content" => "lol",
+      "tag" => @emoji_tags ++ @misc_tags,
+      "emoji" => %{
+        "mikoto_smile2" => "https://example.org/emoji/biribiri/mikoto_smile2.png",
+        "mikoto_smile3" => "https://example.org/emoji/biribiri/mikoto_smile3.png",
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png",
+        "test" => "https://example.org/test.png"
+      },
+      "to" => ["https://example.org/self", Pleroma.Constants.as_public()],
+      "cc" => ["https://example.org/someone"]
+    },
+    "to" => ["https://example.org/self", Pleroma.Constants.as_public()],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  @status_data_with_history %{
+    "type" => "Create",
+    "object" =>
+      @status_data["object"]
+      |> Map.merge(%{
+        "formerRepresentations" => %{
+          "type" => "OrderedCollection",
+          "orderedItems" => [@status_data["object"] |> Map.put("content", "older")],
+          "totalItems" => 1
+        }
+      }),
+    "to" => ["https://example.org/self", Pleroma.Constants.as_public()],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  @emoji_react_data %{
+    "type" => "EmojiReact",
+    "tag" => [@emoji_tags |> Enum.at(3)],
+    "object" => "https://example.org/someobject",
+    "to" => ["https://example.org/self"],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  @emoji_react_data_matching_regex %{
+    "type" => "EmojiReact",
+    "tag" => [@emoji_tags |> Enum.at(1)],
+    "object" => "https://example.org/someobject",
+    "to" => ["https://example.org/self"],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  @emoji_react_data_matching_nothing %{
+    "type" => "EmojiReact",
+    "tag" => [@emoji_tags |> Enum.at(2)],
+    "object" => "https://example.org/someobject",
+    "to" => ["https://example.org/self"],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  @emoji_react_data_unicode %{
+    "type" => "EmojiReact",
+    "content" => "😍",
+    "object" => "https://example.org/someobject",
+    "to" => ["https://example.org/self"],
+    "cc" => ["https://example.org/someone"]
+  }
+
+  describe "remove_url" do
+    setup do
+      clear_config([:mrf_emoji, :remove_url], [
+        "https://example.org/test.png",
+        ~r{/biribiri/mikoto_smile[23]\.png},
+        "nekomimi_girl_emoji"
+      ])
+
+      :ok
+    end
+
+    test "processes user" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @user_data)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      assert %{"tag" => ^expected_tags} = filtered
+    end
+
+    test "processes status" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{"object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}} = filtered
+    end
+
+    test "processes status with history" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data_with_history)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{
+               "object" => %{
+                 "tag" => ^expected_tags,
+                 "emoji" => ^expected_emoji,
+                 "formerRepresentations" => %{"orderedItems" => [item]}
+               }
+             } = filtered
+
+      assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
+    end
+
+    test "processes updates" do
+      {:ok, filtered} =
+        MRF.filter_one(EmojiPolicy, @status_data_with_history |> Map.put("type", "Update"))
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{
+               "object" => %{
+                 "tag" => ^expected_tags,
+                 "emoji" => ^expected_emoji,
+                 "formerRepresentations" => %{"orderedItems" => [item]}
+               }
+             } = filtered
+
+      assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
+    end
+
+    test "processes EmojiReact" do
+      assert {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data)
+
+      assert {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_regex)
+
+      assert {:ok, @emoji_react_data_matching_nothing} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_nothing)
+
+      assert {:ok, @emoji_react_data_unicode} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_unicode)
+    end
+  end
+
+  describe "remove_shortcode" do
+    setup do
+      clear_config([:mrf_emoji, :remove_shortcode], [
+        "test",
+        ~r{mikoto_s},
+        "nekomimi_girl_emoji"
+      ])
+
+      :ok
+    end
+
+    test "processes user" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @user_data)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      assert %{"tag" => ^expected_tags} = filtered
+    end
+
+    test "processes status" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{"object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}} = filtered
+    end
+
+    test "processes status with history" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data_with_history)
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{
+               "object" => %{
+                 "tag" => ^expected_tags,
+                 "emoji" => ^expected_emoji,
+                 "formerRepresentations" => %{"orderedItems" => [item]}
+               }
+             } = filtered
+
+      assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
+    end
+
+    test "processes updates" do
+      {:ok, filtered} =
+        MRF.filter_one(EmojiPolicy, @status_data_with_history |> Map.put("type", "Update"))
+
+      expected_tags = [@emoji_tags |> Enum.at(2)] ++ @misc_tags
+
+      expected_emoji = %{
+        "nekomimi_girl_emoji_007" =>
+          "https://example.org/emoji/nekomimi_girl_emoji/nekomimi_girl_emoji_007.png"
+      }
+
+      assert %{
+               "object" => %{
+                 "tag" => ^expected_tags,
+                 "emoji" => ^expected_emoji,
+                 "formerRepresentations" => %{"orderedItems" => [item]}
+               }
+             } = filtered
+
+      assert %{"tag" => ^expected_tags, "emoji" => ^expected_emoji} = item
+    end
+
+    test "processes EmojiReact" do
+      assert {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data)
+
+      assert {:reject, "[EmojiPolicy] Rejected for having disallowed emoji"} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_regex)
+
+      assert {:ok, @emoji_react_data_matching_nothing} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_matching_nothing)
+
+      assert {:ok, @emoji_react_data_unicode} ==
+               MRF.filter_one(EmojiPolicy, @emoji_react_data_unicode)
+    end
+  end
+
+  describe "federated_timeline_removal_url" do
+    setup do
+      clear_config([:mrf_emoji, :federated_timeline_removal_url], [
+        "https://example.org/test.png",
+        ~r{/biribiri/mikoto_smile[23]\.png},
+        "nekomimi_girl_emoji"
+      ])
+
+      :ok
+    end
+
+    test "processes status" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data)
+
+      expected_tags = @status_data["object"]["tag"]
+      expected_emoji = @status_data["object"]["emoji"]
+
+      expected_to = ["https://example.org/self"]
+      expected_cc = [Pleroma.Constants.as_public(), "https://example.org/someone"]
+
+      assert %{
+               "to" => ^expected_to,
+               "cc" => ^expected_cc,
+               "object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}
+             } = filtered
+    end
+
+    test "ignore updates" do
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, @status_data |> Map.put("type", "Update"))
+
+      expected_tags = @status_data["object"]["tag"]
+      expected_emoji = @status_data["object"]["emoji"]
+
+      expected_to = ["https://example.org/self", Pleroma.Constants.as_public()]
+      expected_cc = ["https://example.org/someone"]
+
+      assert %{
+               "to" => ^expected_to,
+               "cc" => ^expected_cc,
+               "object" => %{"tag" => ^expected_tags, "emoji" => ^expected_emoji}
+             } = filtered
+    end
+
+    test "processes status with history" do
+      status =
+        @status_data_with_history
+        |> put_in(["object", "tag"], @misc_tags)
+        |> put_in(["object", "emoji"], %{})
+
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, status)
+
+      expected_tags = @status_data["object"]["tag"]
+      expected_emoji = @status_data["object"]["emoji"]
+
+      expected_to = ["https://example.org/self"]
+      expected_cc = [Pleroma.Constants.as_public(), "https://example.org/someone"]
+
+      assert %{
+               "to" => ^expected_to,
+               "cc" => ^expected_cc,
+               "object" => %{
+                 "formerRepresentations" => %{
+                   "orderedItems" => [%{"tag" => ^expected_tags, "emoji" => ^expected_emoji}]
+                 }
+               }
+             } = filtered
+    end
+  end
+
+  describe "edge cases" do
+    setup do
+      clear_config([:mrf_emoji, :remove_url], [
+        "https://example.org/test.png",
+        ~r{/biribiri/mikoto_smile[23]\.png},
+        "nekomimi_girl_emoji"
+      ])
+
+      :ok
+    end
+
+    test "non-statuses" do
+      answer = @status_data |> put_in(["object", "type"], "Answer")
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, answer)
+
+      assert filtered == answer
+    end
+
+    test "without tag" do
+      status = @status_data |> Map.put("object", Map.drop(@status_data["object"], ["tag"]))
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, status)
+
+      refute Map.has_key?(filtered["object"], "tag")
+    end
+
+    test "without emoji" do
+      status = @status_data |> Map.put("object", Map.drop(@status_data["object"], ["emoji"]))
+      {:ok, filtered} = MRF.filter_one(EmojiPolicy, status)
+
+      refute Map.has_key?(filtered["object"], "emoji")
+    end
+  end
+end

test/pleroma/web/activity_pub/mrf/utils_test.exs

@@ -0,0 +1,19 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.UtilsTest do
+  use Pleroma.DataCase, async: true
+
+  alias Pleroma.Web.ActivityPub.MRF.Utils
+
+  describe "describe_regex_or_string/1" do
+    test "describes regex" do
+      assert "~r/foo/i" == Utils.describe_regex_or_string(~r/foo/i)
+    end
+
+    test "returns string as-is" do
+      assert "foo" == Utils.describe_regex_or_string("foo")
+    end
+  end
+end