Implement client invite endpoint

Refactor room server to automatically determine auth events
Add documentation in various places

lib/matrix_server_web/federation/controllers/event_controller.ex

@@ -8,6 +8,11 @@ defmodule MatrixServerWeb.Federation.EventController do
   alias MatrixServer.{Repo, Event, RoomServer}
   alias MatrixServerWeb.Federation.Transaction
 
+  @doc """
+  Retrieves a single event.
+
+  Action for GET /_matrix/federation/v1/event/{eventId}.
+  """
   def event(%Plug.Conn{assigns: %{origin: origin}} = conn, %{"event_id" => event_id}) do
     query =
       Event
@@ -39,6 +44,11 @@ defmodule MatrixServerWeb.Federation.EventController do
 
   def event(conn, _), do: put_error(conn, :missing_param)
 
+  @doc """
+  Retrieves a snapshot of a room's state at a given event.
+
+  Action for GET /_matrix/federation/v1/state/{roomId}.
+  """
   def state(%Plug.Conn{assigns: %{origin: origin}} = conn, %{
         "event_id" => event_id,
         "room_id" => room_id
@@ -48,6 +58,11 @@ defmodule MatrixServerWeb.Federation.EventController do
 
   def state(conn, _), do: put_error(conn, :missing_param)
 
+  @doc """
+  Retrieves a snapshot of a room's state at a given event, in the form of event IDs.
+
+  Action for GET /_matrix/federation/v1/state_ids/{roomId}.
+  """
   def state_ids(%Plug.Conn{assigns: %{origin: origin}} = conn, %{
         "event_id" => event_id,
         "room_id" => room_id

lib/matrix_server_web/federation/controllers/key_controller.ex

@@ -5,6 +5,11 @@ defmodule MatrixServerWeb.Federation.KeyController do
 
   alias MatrixServer.KeyServer
 
+  @doc """
+  Gets the homeserver's published signing keys.
+
+  Action for GET /_matrix/key/v2/server/{keyId}.
+  """
   def get_signing_keys(conn, _params) do
     keys =
       KeyServer.get_own_signing_keys()

lib/matrix_server_web/federation/controllers/query_controller.ex

@@ -31,6 +31,12 @@ defmodule MatrixServerWeb.Federation.QueryController do
     end
   end
 
+  @doc """
+  Performs a query to get profile information, such as a display name or avatar,
+  for a given user.
+
+  Action for GET /_matrix/federation/v1/query/profile.
+  """
   def profile(conn, params) do
     with {:ok, %ProfileRequest{user_id: %UserId{localpart: localpart, domain: domain}}} <-
            ProfileRequest.validate(params) do