StaticFE: Prioritize json in requests.

lib/pleroma/plugs/static_fe_plug.ex

@@ -9,7 +9,7 @@ defmodule Pleroma.Plugs.StaticFEPlug do
   def init(options), do: options
 
   def call(conn, _) do
-    if enabled?() and accepts_html?(conn) do
+    if enabled?() and requires_html?(conn) do
       conn
       |> StaticFEController.call(:show)
       |> halt()
@@ -20,10 +20,13 @@ def call(conn, _) do
 
   defp enabled?, do: Pleroma.Config.get([:static_fe, :enabled], false)
 
-  defp accepts_html?(conn) do
+  defp requires_html?(conn) do
     case get_req_header(conn, "accept") do
-      [accept | _] -> String.contains?(accept, "text/html")
+      [accept | _] ->
-      _ -> false
+        !String.contains?(accept, "json") && String.contains?(accept, "text/html")
+
+      _ ->
+        false
     end
   end
 end

test/web/static_fe/static_fe_controller_test.exs

@@ -87,6 +87,20 @@ test "single notice page", %{conn: conn, user: user} do
       assert html =~ "testing a thing!"
     end
 
+    test "redirects to json if requested", %{conn: conn, user: user} do
+      {:ok, activity} = CommonAPI.post(user, %{status: "testing a thing!"})
+
+      conn =
+        conn
+        |> put_req_header(
+          "accept",
+          "Accept: application/activity+json, application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\", text/html"
+        )
+        |> get("/notice/#{activity.id}")
+
+      assert redirected_to(conn, 302) =~ activity.data["object"]
+    end
+
     test "filters HTML tags", %{conn: conn} do
       user = insert(:user)
       {:ok, activity} = CommonAPI.post(user, %{status: "<script>alert('xss')</script>"})