implement client heartbeat #460.

server/pkg/types/event/events.go

@@ -9,6 +9,10 @@ const (
 	SYSTEM_HEARTBEAT  = "system/heartbeat"
 )
 
+const (
+	CLIENT_HEARTBEAT = "client/heartbeat"
+)
+
 const (
 	SIGNAL_REQUEST   = "signal/request"
 	SIGNAL_RESTART   = "signal/restart"

server/pkg/types/session.go

@@ -47,6 +47,7 @@ type Settings struct {
 	ImplicitHosting   bool `json:"implicit_hosting"`
 	InactiveCursors   bool `json:"inactive_cursors"`
 	MercifulReconnect bool `json:"merciful_reconnect"`
+	HeartbeatInterval int  `json:"heartbeat_interval"`
 
 	// plugin scope
 	Plugins PluginSettings `json:"plugins"`