Update

lib/nulla_web/controllers/generic/webfinger_json.ex

@@ -0,0 +1,50 @@
+defmodule NullaWeb.Generic.WebfingerJSON do
+  alias Nulla.Actors.Actor
+
+  @doc """
+  Renders a webfinger.
+  """
+  def show(actor) do
+    data(actor)
+  end
+
+  defp data(%Actor{} = actor) do
+    data = [
+      subject: actor.acct,
+      aliases: [
+        actor.url,
+        actor.ap_id
+      ],
+      links: [
+        Jason.OrderedObject.new(
+          rel: "http://webfinger.net/rel/profile-page",
+          type: "text/html",
+          href: actor.url
+        ),
+        Jason.OrderedObject.new(
+          rel: "self",
+          type: "application/activity+json",
+          href: actor.ap_id
+        )
+      ]
+    ]
+
+    data =
+      if actor.icon do
+        Keyword.update!(data, :links, fn links ->
+          links ++
+            [
+              Jason.OrderedObject.new(
+                rel: "http://webfinger.net/rel/avatar",
+                type: Map.get(actor.icon, :mediaType),
+                href: Map.get(actor.icon, :url)
+              )
+            ]
+        end)
+      else
+        data
+      end
+
+    Jason.OrderedObject.new(data)
+  end
+end