Validate alias IDs

CHANGELOG.md

@@ -63,6 +63,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Support pagination in emoji packs API (for packs and for files in pack)
 - Support for viewing instances favicons next to posts and accounts
 - Added Pleroma.Upload.Filter.Exiftool as an alternate EXIF stripping mechanism targeting GPS/location metadata.
+- Ability to set ActivityPub aliases for follower migration.
 
 <details>
   <summary>API Changes</summary>

lib/pleroma/user.ex

@@ -47,6 +47,8 @@ defmodule Pleroma.User do
 
   # credo:disable-for-next-line Credo.Check.Readability.MaxLineLength
   @email_regex ~r/^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/
+  # credo:disable-for-next-line Credo.Check.Readability.MaxLineLength
+  @url_regex ~r/https?:\/\/[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&\/=]*)/
 
   @strict_local_nickname_regex ~r/^[a-zA-Z\d]+$/
   @extended_local_nickname_regex ~r/^[a-zA-Z\d_-]+$/
@@ -2278,6 +2280,7 @@ def add_aliases(%User{} = user, aliases) when is_list(aliases) do
 
     user
     |> change(%{ap_aliases: alias_set})
+    |> validate_ap_aliases()
     |> Repo.update()
   end
 
@@ -2290,6 +2293,16 @@ def delete_aliases(%User{} = user, aliases) when is_list(aliases) do
 
     user
     |> change(%{ap_aliases: alias_set})
+    |> validate_ap_aliases()
     |> Repo.update()
   end
+
+  defp validate_ap_aliases(changeset) do
+    validate_change(changeset, :ap_aliases, fn :ap_aliases, ap_aliases ->
+      case Enum.all?(ap_aliases, fn a -> Regex.match?(@url_regex, a) end) do
+        true -> []
+        false -> [ap_aliases: "Invalid ap_id format. Must be a URL."]
+      end
+    end)
+  end
 end

test/user_test.exs

@@ -1876,6 +1876,13 @@ test "add_aliases/2" do
            ]
   end
 
+  test "add_aliases/2 with invalid alias" do
+    user = insert(:user)
+    {:error, _} = User.add_aliases(user, ["invalid_alias"])
+    {:error, _} = User.add_aliases(user, ["http://still_invalid"])
+    {:error, _} = User.add_aliases(user, ["http://validalias.com/users/dude", "invalid_alias"])
+  end
+
   test "delete_aliases/2" do
     user =
       insert(:user,