Add transaction IDs to messages and handle on the server

server/src/session_server.erl

@@ -23,13 +23,16 @@ handle_cast(_Msg, State) ->
 
 handle_info({ssl, Socket, Data}, State) ->
 	case 'StudySystemProtocol':decode('Request', Data) of
-		{ok, {ping, _}} ->
+		{ok, {'Request', TransactionId, RequestBody}} ->
+			ResponseBody = map_request(RequestBody),
 			{ok, Encoded} = 'StudySystemProtocol':encode(
-							  'Response', {ack, 'NULL'}),
+							  'Response',
+							  {'Response', TransactionId, ResponseBody}),
 			ok = ssl:send(Socket, Encoded);
 		{error, {asn1, _Reason}} ->
 			{ok, Encoded} = 'StudySystemProtocol':encode(
-							  'Response', {error, invalidRequest}),
+							  'Response',
+							  {'Response', -1, {error, invalidRequest}}),
 			ok = ssl:send(Socket, Encoded)
 	end,
 	{noreply, State};
@@ -45,3 +48,8 @@ terminate(_Reason, #{socket := Socket}) ->
 
 code_change(_OldVsn, State, _Extra) ->
 	{ok, State}.
+
+map_request({ping, 'NULL'}) ->
+	{ack, 'NULL'};
+map_request(_) ->
+	{error, invalidRequest}.