Merge pull request 'web/metadata: provide alternate link for ActivityPub' (#905) from Oneric/akkoma:metadata_aplink into develop

Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/905

lib/pleroma/web/metadata.ex

@@ -64,7 +64,11 @@ def activity_nsfw?(_) do
 
   defp activated_providers do
     unless Pleroma.Config.restrict_unauthenticated_access?(:activities, :local) do
-      [Pleroma.Web.Metadata.Providers.Feed | Pleroma.Config.get([__MODULE__, :providers], [])]
+      [
+        Pleroma.Web.Metadata.Providers.Feed,
+        Pleroma.Web.Metadata.Providers.ApUrl
+        | Pleroma.Config.get([__MODULE__, :providers], [])
+      ]
     else
       []
     end

lib/pleroma/web/metadata/providers/ap_url.ex

@@ -0,0 +1,35 @@
+# Akkoma: Magically expressive social media
+# Copyright © 2025 Akkoma Authors <https://akkoma.dev/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.Metadata.Providers.ApUrl do
+  alias Pleroma.Web.Metadata.Providers.Provider
+
+  @behaviour Provider
+
+  defp alt_link(uri, type) do
+    {
+      :link,
+      [rel: "alternate", href: uri, type: type],
+      []
+    }
+  end
+
+  defp ap_alt_links(uri) do
+    [
+      alt_link(uri, "application/activity+json"),
+      alt_link(uri, "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\"")
+    ]
+  end
+
+  @impl Provider
+  def build_tags(%{object: %{data: %{"id" => ap_id}}}) when is_binary(ap_id) do
+    ap_alt_links(ap_id)
+  end
+
+  def build_tags(%{user: %{ap_id: ap_id}}) when is_binary(ap_id) do
+    ap_alt_links(ap_id)
+  end
+
+  def build_tags(_), do: []
+end

test/pleroma/web/metadata/providers/ap_url_test.exs

@@ -0,0 +1,31 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.Metadata.Providers.ApUrlTest do
+  use Pleroma.DataCase, async: true
+  import Pleroma.Factory
+  alias Pleroma.Web.Metadata.Providers.ApUrl
+
+  @ap_type_compliant "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\""
+  @ap_type_mastodon "application/activity+json"
+
+  test "it preferentially renders a link to a post" do
+    user = insert(:user)
+    note = insert(:note, user: user)
+
+    assert ApUrl.build_tags(%{object: note, user: user}) == [
+             {:link, [rel: "alternate", href: note.data["id"], type: @ap_type_mastodon], []},
+             {:link, [rel: "alternate", href: note.data["id"], type: @ap_type_compliant], []}
+           ]
+  end
+
+  test "it renders a link to a user" do
+    user = insert(:user)
+
+    assert ApUrl.build_tags(%{user: user}) == [
+             {:link, [rel: "alternate", href: user.ap_id, type: @ap_type_mastodon], []},
+             {:link, [rel: "alternate", href: user.ap_id, type: @ap_type_compliant], []}
+           ]
+  end
+end

test/pleroma/web/static_fe/static_fe_controller_test.exs

@@ -321,6 +321,16 @@ defp meta_find_twitter(document, name) do
     Floki.find(document, "head>meta[name=\"twitter:" <> name <> "\"]")
   end
 
+  defp meta_find_alt_links(document) do
+    Floki.find(document, "head>link[rel=\"alternate\"]")
+    |> Enum.map(fn {_, attr, _} ->
+      {
+        :proplists.get_value("type", attr),
+        :proplists.get_value("href", attr)
+      }
+    end)
+  end
+
   # Detailed metadata tests are already done for each builder individually, so just
   # one check per type of content should suffice to ensure we're calling the providers correctly
   describe "metadata tags for" do
@@ -350,6 +360,8 @@ test "user profile", %{conn: conn, user: user, user_avatar_url: user_avatar_url}
       [{"meta", tw_desc, _}] = meta_find_twitter(document, "description")
       [{"meta", tw_img, _}] = meta_find_twitter(document, "image")
 
+      alt_links = meta_find_alt_links(document)
+
       assert meta_content(og_type) == "article"
       assert meta_content(og_title) == Pleroma.Web.Metadata.Utils.user_name_string(user)
       assert meta_content(og_url) == user.ap_id
@@ -362,6 +374,8 @@ test "user profile", %{conn: conn, user: user, user_avatar_url: user_avatar_url}
       assert meta_content(tw_title) == meta_content(og_title)
       assert meta_content(tw_desc) == meta_content(og_desc)
       assert meta_content(tw_img) == meta_content(og_img)
+
+      assert Enum.any?(alt_links, fn e -> e == {"application/activity+json", user.ap_id} end)
     end
 
     test "text-only post", %{conn: conn, user: user, user_avatar_url: user_avatar_url} do
@@ -386,6 +400,8 @@ test "text-only post", %{conn: conn, user: user, user_avatar_url: user_avatar_ur
       [{"meta", tw_desc, _}] = meta_find_twitter(document, "description")
       [{"meta", tw_img, _}] = meta_find_twitter(document, "image")
 
+      alt_links = meta_find_alt_links(document)
+
       assert meta_content(og_type) == "article"
       assert meta_content(og_title) == Pleroma.Web.Metadata.Utils.user_name_string(user)
       assert meta_content(og_url) == activity.data["id"]
@@ -398,6 +414,10 @@ test "text-only post", %{conn: conn, user: user, user_avatar_url: user_avatar_ur
       assert meta_content(tw_title) == meta_content(og_title)
       assert meta_content(tw_desc) == meta_content(og_desc)
       assert meta_content(tw_img) == meta_content(og_img)
+
+      assert Enum.any?(alt_links, fn e ->
+               e == {"application/activity+json", activity.object.data["id"]}
+             end)
     end
 
     test "post with attachments", %{conn: conn, user: user} do