fix: Fix various bugs with following

lib/activity_pub/headers.ex

@@ -10,6 +10,23 @@ defmodule ActivityPub.Headers do
   ]
 
   def signing_headers(method, url, body, actor_url, private_key) do
+    url = case url do
+      url when is_struct(url, URI) ->
+        url
+      url when is_binary(url) ->
+        URI.parse(url)
+      end
+
+    private_key = case private_key do
+      "-----BEGIN" <> _ = key_pem ->
+        key_pem
+        |> :public_key.pem_decode()
+        |> hd()
+        |> :public_key.pem_entry_decode()
+      private_key ->
+        private_key
+      end
+
     method = String.downcase("#{method}")
     date = DateTime.utc_now() |> Calendar.strftime(@http_date_format)
     host = url.host
@@ -35,9 +52,11 @@ defmodule ActivityPub.Headers do
   end
 
   def verify(method, path, headers, actor_fetcher \\ &fetch_actor_key/1) do
+    dbg(headers)
+
     {_key, signature_header} = Enum.find(headers, fn {key, _} -> key == "signature" end)
 
-    signature_kv = SignatureSplitter.split(signature_header)
+    signature_kv = SignatureSplitter.split(signature_header) |> dbg()
     key_id = find_value(signature_kv, "keyId")
     signature = signature_kv |> find_value("signature") |> Base.decode64!()
     signing_text_headers = signature_kv |> find_value("headers") |> String.split(" ")
@@ -65,6 +84,7 @@ defmodule ActivityPub.Headers do
       value = find_value(header_pairs, header_name)
       "#{header_name}: #{value}\n"
     end)
+    |> String.trim()
   end
 
   def split_signature_header(signature_header) do
@@ -79,6 +99,8 @@ defmodule ActivityPub.Headers do
   end
 
   defp find_value(headers, key) do
+    key = String.downcase(key)
+
     Enum.find_value(headers, fn {key_candidate, value} ->
       String.downcase(key_candidate) == key && value
     end)
@@ -90,7 +112,7 @@ defmodule ActivityPub.Headers do
         key_map = body["publicKey"]
 
         if key_map["id"] == key_id do
-          [public_key | _] =
+          public_key =
             :public_key.pem_decode(key_map["publicKeyPem"])
             |> hd()
             |> :public_key.pem_entry_decode()

lib/postland/activities.ex

@@ -26,6 +26,8 @@ defmodule Postland.Activities do
   def cause_effects(%Activity{actor_id: actor_id, type: "Accept", data: %{"object" => %{"type" => "Follow"}}} = activity) do
     case Follows.get(Postland.my_actor_id(), actor_id) do
       nil ->
+        # TODO: Need to handle the scenario where the we're following has an alias (/@foobar becomes /users/foobar by the time
+        #   they Accept)
         Logger.warning("Got accept for a follow we don't have in the db: #{actor_id}")
 
         {:ok, activity}
@@ -50,5 +52,5 @@ defmodule Postland.Activities do
     end
   end
 
-  def cause_effects(activity), do: activity
+  def cause_effects(activity), do: {:ok, activity}
 end

lib/postland/follows.ex

@@ -23,7 +23,7 @@ defmodule Postland.Follows do
     encoded_followee = Base.url_encode64(to_actor_id)
     encoded_follower = Base.url_encode64(Postland.my_actor_id())
 
-    actor = ActivityPub.fetch_actor(to_actor_id)
+    {:ok, actor} = ActivityPub.fetch_actor(to_actor_id)
     inbox = Map.get(actor, "inbox")
     follow_request = %{
         "@context" => "https://www.w3.org/ns/activitystreams",

lib/postland_web/controllers/actor_controller.ex

@@ -2,6 +2,8 @@ defmodule PostlandWeb.ActorController do
   use PostlandWeb, :controller
 
   def get(conn, _params) do
-    render(conn, :actor, %{})
+    conn
+    |> Plug.Conn.put_resp_header("content-type", "application/activity+json")
+    |> render(:actor, %{})
   end
 end

lib/postland_web/controllers/inbox_controller.ex

@@ -10,13 +10,13 @@ defmodule PostlandWeb.InboxController do
     if Headers.verify(conn.method, conn.request_path, conn.req_headers) do
       case Activities.process_activity(params) do
         {:ok, _activity} ->
-          render(conn, :ok)
+          Plug.Conn.send_resp(conn, 200, Jason.encode!(params))
         error ->
           Logger.error(error)
-          render(conn, :unprocessable_entity)
+          Plug.Conn.send_resp(conn, 422, "unprocessable entity")
       end
     else
-      render(conn, :forbidden)
+      Plug.Conn.send_resp(conn, 403, "forbidden")
     end
   end
 end

lib/postland_web/router.ex

@@ -27,7 +27,7 @@ defmodule PostlandWeb.Router do
     get "/.well-known/webfinger", WebfingerController, :get
 
     get "/actor", ActorController, :get
-    get "/inbox", InboxController, :post
+    post "/inbox", InboxController, :post
     get "/outbox", OutboxController, :get
   end