Implement client get room stat endpoint

README.md

@@ -61,6 +61,7 @@ Here, implemented and some unimplemented features are listed.
 - PUT /_matrix/client/r0/rooms/{roomId}/state/{eventType}/{stateKey}
 - PUT /_matrix/client/r0/rooms/{roomId}/send/{eventType}/{txnId}
 - GET /_matrix/client/r0/rooms/{roomId}/messages: Except filtering.
+- GET /_matrix/client/r0/rooms/{roomId}/state
 - GET /_matrix/client/r0/directory/list/room/{roomId}
 - PUT /_matrix/client/r0/directory/list/room/{roomId}
 - GET /_matrix/client/r0/capabilities

lib/architex/room_server.ex

@@ -189,6 +189,17 @@ defmodule Architex.RoomServer do
     GenServer.call(pid, {:send_state_event, account, event_type, content, state_key})
   end
 
+  @doc """
+  Get the current state of a room.
+  If the requesting user is not a member of the room,
+  get the state when the user left the room.
+  If the user has never been in the room, return an error.
+  """
+  @spec get_current_state(pid(), Account.t()) :: {:ok, [Event.t()]} | :error
+  def get_current_state(pid, account) do
+    GenServer.call(pid, {:get_current_state, account})
+  end
+
   ### Implementation
 
   @impl true
@@ -424,6 +435,24 @@ defmodule Architex.RoomServer do
     end
   end
 
+  def handle_call({:get_current_state, account}, _from, %{state_set: state_set} = state) do
+    mxid = Account.get_mxid(account)
+
+    case state_set[{"m.room.member", mxid}] do
+      %Event{content: %{"membership" => "join"}} ->
+        # Get the current state of the room.
+        {:reply, {:ok, Map.values(state_set)}, state}
+
+      %Event{content: %{"membership" => "leave"}} = event ->
+        # Get the state of the room, after leaving.
+        state_set = StateResolution.resolve(event)
+        {:reply, {:ok, Map.values(state_set)}, state}
+
+      _ ->
+        {:reply, :error, state}
+    end
+  end
+
   @spec process_event_with_txn(t(), Room.t(), Device.t(), %Event{}, String.t()) ::
           (() -> {t(), Room.t(), String.t()} | {:error, atom()})
   defp process_event_with_txn(

lib/architex/schema/event/formatters.ex

@@ -4,33 +4,10 @@ defmodule Architex.Event.Formatters do
   """
   alias Architex.Event
 
-  @spec messages_response(Event.t()) :: map()
-  def messages_response(%Event{
-        content: content,
-        type: type,
-        id: event_id,
-        sender: sender,
-        origin_server_ts: origin_server_ts,
-        unsigned: unsigned,
-        room_id: room_id,
-        state_key: state_key
-      }) do
-    data = %{
-      content: content,
-      type: type,
-      event_id: event_id,
-      sender: to_string(sender),
-      origin_server_ts: origin_server_ts,
-      room_id: room_id
-    }
-
-    data = if unsigned, do: Map.put(data, :unsigned, unsigned), else: data
-    data = if state_key, do: Map.put(data, :state_key, state_key), else: data
-
-    data
-  end
-
-  def sync_response(%Event{
+  @doc """
+  Event format with keys that all formats have in common.
+  """
+  def base_client_response(%Event{
         content: content,
         type: type,
         id: event_id,
@@ -46,11 +23,37 @@ defmodule Architex.Event.Formatters do
       origin_server_ts: origin_server_ts
     }
 
-    data = if unsigned, do: Map.put(data, :unsigned, unsigned), else: data
-
-    data
+    if unsigned, do: Map.put(data, :unsigned, unsigned), else: data
   end
 
+  @doc """
+  The base event format, with room_id and state_key added.
+  Used in the client /messages response.
+  """
+  @spec messages_response(Event.t()) :: map()
+  def messages_response(%Event{room_id: room_id, state_key: state_key} = event) do
+    data =
+      base_client_response(event)
+      |> Map.put(:room_id, room_id)
+
+    if state_key, do: Map.put(data, :state_key, state_key), else: data
+  end
+
+  @doc """
+  The event format used in the client /state response.
+  TODO: prev_content
+  """
+  def state_response(event), do: messages_response(event)
+
+  @doc """
+  The base event format, used in the client /sync response.
+  """
+  @spec sync_response(Event.t()) :: map()
+  def sync_response(event), do: base_client_response(event)
+
+  @doc """
+  The PDU format used for federation.
+  """
   @spec as_pdu(Event.t()) :: map()
   def as_pdu(%Event{
         auth_events: auth_events,

lib/architex_web/client/controllers/room_controller.ex

@@ -311,4 +311,33 @@ defmodule ArchitexWeb.Client.RoomController do
       {:error, _} -> put_error(conn, :bad_json)
     end
   end
+
+  @doc """
+  Get the state events for the current state of a room.
+
+  Action for GET /_matrix/client/r0/rooms/{roomId}/state.
+  """
+  def state(%Conn{assigns: %{account: account}} = conn, %{"room_id" => room_id}) do
+    case RoomServer.get_room_server(room_id) do
+      {:ok, pid} ->
+        case RoomServer.get_current_state(pid, account) do
+          {:ok, events} ->
+            events = Enum.map(events, &Event.Formatters.state_response/1)
+
+            conn
+            |> put_status(200)
+            |> json(events)
+
+          :error ->
+            put_error(
+              conn,
+              :forbidden,
+              "You aren't a member of the room and weren't previously a member of the room."
+            )
+        end
+
+      {:error, :not_found} ->
+        put_error(conn, :not_found, "The given room was not found.")
+    end
+  end
 end

lib/architex_web/router.ex

@@ -87,7 +87,11 @@ defmodule ArchitexWeb.Router do
         post "/unban", RoomController, :unban
         put "/send/:event_type/:txn_id", RoomController, :send_message_event
         get "/messages", RoomController, :messages
-        put "/state/:event_type/*state_key", RoomController, :send_state_event
+
+        scope "/state" do
+          get "/", RoomController, :state
+          put "/:event_type/*state_key", RoomController, :send_state_event
+        end
       end
     end
   end