Add function to query whether server participates in a room

Move from integer timestamps to datetimes

lib/matrix_server_web/federation/controllers/key_controller.ex

@@ -5,8 +5,6 @@ defmodule MatrixServerWeb.Federation.KeyController do
 
   alias MatrixServer.KeyServer
 
-  @key_valid_time_ms 1000 * 60 * 24 * 30
-
   def get_signing_keys(conn, _params) do
     keys =
       KeyServer.get_own_signing_keys()
@@ -14,11 +12,15 @@ defmodule MatrixServerWeb.Federation.KeyController do
         {key_id, %{"key" => key}}
       end)
 
+    # TODO: Consider using TimeX.
+    # Valid for one month.
+    valid_until = DateTime.utc_now() |> DateTime.add(60 * 60 * 24 * 30, :second)
+
     data = %{
       server_name: MatrixServer.server_name(),
       verify_keys: keys,
       old_verify_keys: %{},
-      valid_until_ts: System.os_time(:millisecond) + @key_valid_time_ms
+      valid_until_ts: valid_until
     }
 
     case KeyServer.sign_object(data) do