From d1c4d0740467455b4fd158c9c3d1b79e500a79f9 Mon Sep 17 00:00:00 2001
From: Oneric <oneric@oneric.stub>
Date: Fri, 8 Mar 2024 03:06:40 +0100
Subject: [PATCH] Convert StealEmoji to pack.json

This will decouple filenames from shortcodes and
allow more image formats to work instead of only
those included in the auto-load glob. (Albeit we
still saved other formats to disk, wasting space)

Furthermore, this will allow us to make
final URL paths infeasible to predict.
---
 lib/pleroma/emoji/pack.ex                     | 16 ++++-
 .../activity_pub/mrf/steal_emoji_policy.ex    | 58 +++++++++++++------
 2 files changed, 56 insertions(+), 18 deletions(-)

diff --git a/lib/pleroma/emoji/pack.ex b/lib/pleroma/emoji/pack.ex
index 30ed5a8bd..f007cde65 100644
--- a/lib/pleroma/emoji/pack.ex
+++ b/lib/pleroma/emoji/pack.ex
@@ -92,7 +92,7 @@ defmodule Pleroma.Emoji.Pack do
     end)
   end
 
-  @spec add_file(t(), String.t(), Path.t(), Plug.Upload.t()) ::
+  @spec add_file(t(), String.t(), Path.t(), Plug.Upload.t() | binary()) ::
           {:ok, t()}
           | {:error, File.posix() | atom()}
   def add_file(%Pack{} = pack, _, _, %Plug.Upload{content_type: "application/zip"} = file) do
@@ -140,6 +140,14 @@ defmodule Pleroma.Emoji.Pack do
   end
 
   def add_file(%Pack{} = pack, shortcode, filename, %Plug.Upload{} = file) do
+    try_add_file(pack, shortcode, filename, file)
+  end
+
+  def add_file(%Pack{} = pack, shortcode, filename, filedata) when is_binary(filedata) do
+    try_add_file(pack, shortcode, filename, filedata)
+  end
+
+  defp try_add_file(%Pack{} = pack, shortcode, filename, file) do
     with :ok <- validate_not_empty([shortcode, filename]),
          :ok <- validate_emoji_not_exists(shortcode),
          {:ok, updated_pack} <- do_add_file(pack, shortcode, filename, file) do
@@ -485,6 +493,12 @@ defmodule Pleroma.Emoji.Pack do
     end
   end
 
+  defp save_file(file_data, pack, filename) when is_binary(file_data) do
+    file_path = Path.join(pack.path, filename)
+    create_subdirs(file_path)
+    File.write(file_path, file_data, [:binary])
+  end
+
   defp put_emoji(pack, shortcode, filename) do
     files = Map.put(pack.files, shortcode, filename)
     %{pack | files: files, files_count: length(Map.keys(files))}
diff --git a/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex b/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex
index da6b8275d..ed421d93e 100644
--- a/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex
@@ -6,10 +6,41 @@ defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do
   require Logger
 
   alias Pleroma.Config
+  alias Pleroma.Emoji.Pack
 
   @moduledoc "Detect new emojis by their shortcode and steals them"
   @behaviour Pleroma.Web.ActivityPub.MRF.Policy
 
+  @pack_name "stolen"
+
+  defp create_pack() do
+    with {:ok, pack} = Pack.create(@pack_name) do
+      Pack.save_metadata(
+        %{
+          "description" => "Collection of emoji auto-stolen from other instances",
+          "homepage" => Pleroma.Web.Endpoint.url(),
+          "can-download" => false,
+          "share-files" => false
+        },
+        pack
+      )
+    end
+  end
+
+  defp load_or_create_pack() do
+    case Pack.load_pack(@pack_name) do
+      {:ok, pack} -> {:ok, pack}
+      {:error, :enoent} -> create_pack()
+      e -> e
+    end
+  end
+
+  defp add_emoji(shortcode, extension, filedata) do
+    {:ok, pack} = load_or_create_pack()
+    filename = shortcode <> "." <> extension
+    Pack.add_file(pack, shortcode, filename, filedata)
+  end
+
   defp accept_host?(host), do: host in Config.get([:mrf_steal_emoji, :hosts], [])
 
   defp shortcode_matches?(shortcode, pattern) when is_binary(pattern) do
@@ -33,15 +64,16 @@ defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do
     !valid_shortcode? or rejected_shortcode? or emoji_installed?
   end
 
-  defp steal_emoji(%{} = response, {shortcode, extension}, emoji_dir_path) do
-    file_path = Path.join(emoji_dir_path, shortcode <> "." <> extension)
-
-    case File.write(file_path, response.body) do
-      :ok ->
+  defp steal_emoji(%{} = response, {shortcode, extension}) do
+    case add_emoji(shortcode, extension, response.body) do
+      {:ok, _} ->
         shortcode
 
       e ->
-        Logger.warning("MRF.StealEmojiPolicy: Failed to write to #{file_path}: #{inspect(e)}")
+        Logger.warning(
+          "MRF.StealEmojiPolicy: Failed to add #{shortcode}.#{extension}: #{inspect(e)}"
+        )
+
         nil
     end
   end
@@ -56,7 +88,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do
     end
   end
 
-  defp maybe_steal_emoji({shortcode, url}, emoji_dir_path) do
+  defp maybe_steal_emoji({shortcode, url}) do
     url = Pleroma.Web.MediaProxy.url(url)
 
     with {:ok, %{status: status} = response} when status in 200..299 <- Pleroma.HTTP.get(url) do
@@ -64,7 +96,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do
       extension = get_extension_if_safe(response)
 
       if byte_size(response.body) <= size_limit and extension do
-        steal_emoji(response, {shortcode, extension}, emoji_dir_path)
+        steal_emoji(response, {shortcode, extension})
       else
         Logger.debug(
           "MRF.StealEmojiPolicy: :#{shortcode}: at #{url} (#{byte_size(response.body)} B) over size limit (#{size_limit} B)"
@@ -86,18 +118,10 @@ defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do
     if host != Pleroma.Web.Endpoint.host() and accept_host?(host) do
       installed_emoji = Pleroma.Emoji.get_all() |> Enum.map(fn {k, _} -> k end)
 
-      emoji_dir_path =
-        Config.get(
-          [:mrf_steal_emoji, :path],
-          Path.join(Config.get([:instance, :static_dir]), "emoji/stolen")
-        )
-
-      File.mkdir_p(emoji_dir_path)
-
       new_emojis =
         foreign_emojis
         |> Enum.reject(&reject_emoji?(&1, installed_emoji))
-        |> Enum.map(&maybe_steal_emoji(&1, emoji_dir_path))
+        |> Enum.map(&maybe_steal_emoji(&1))
         |> Enum.filter(& &1)
 
       if !Enum.empty?(new_emojis) do