added PING and PONG handling, config

backend/index.js

@@ -28,9 +28,52 @@ const get_siteroot_html = function ({ page_title }) {return `
 `.trim()}
 
 const start_server = function ({ context_meta, config, jsbuild_app_frontend }) {
+	const make_session_object = (ws) => {
+		const map_obj = {
+			ws,
+			closed_by_server: false,
+			id_interval_ping: null,
+			id_timeout_checkpong: null,
+		}
+		const func_check_pong = () => {
+			//console.debug('CHECK PONG')
+			// if this check/timeout was not cancelled yet, indicates it's been "too long" (so, terminate ws)
+			const terminate_session = () => {
+				const code = 1008
+				const reason = 'Policy Violation'
+				map_obj.closed_by_server = true
+				map_obj.ws.close(code, reason)
+				// cleanup here
+				context_meta.ws_map.delete(ws.data.uid)
+				return
+			}
+			terminate_session()
+			// reset this for future ref
+			map_obj.id_timeout_checkpong = null
+			return
+		}
+		const func_periodic_ping = () => {
+			//console.debug('PING')
+			ws.ping()
+			if (config.pong_timeout !== null) {
+				if (map_obj.id_timeout_checkpong === null) {
+					map_obj.id_timeout_checkpong = setTimeout(func_check_pong, config.pong_timeout)
+				}
+				else {
+					// avoid double-schedule of this check
+					console.warn('Unexpected: setTimeout for func_check_pong already scheduled')
+				}
+			}
+			return
+		}
+		if (config.ping_interval !== null) {
+			map_obj.id_interval_ping = setInterval(func_periodic_ping, config.ping_interval)
+		}
+		return map_obj
+	}
 	const server = Bun.serve({
-		hostname: config.host || '127.0.0.1',
+		hostname: config.hostname,
-		port    : config.port || 8800,
+		port    : config.port,
 		async fetch (req, server) {
 			const url = new URL(req.url)
 			let resp
@@ -70,10 +113,8 @@ const start_server = function ({ context_meta, config, jsbuild_app_frontend }) {
 		},
 		websocket: {
 			open: function (ws) {
-				const map_obj = {
+				console.info(['ws open', ws.data.uid])
-					ws,
+				const map_obj = make_session_object(ws)
-					closed_by_server: false,
-				}
 				context_meta.ws_map.set(ws.data.uid, map_obj)
 				return
 			},
@@ -83,6 +124,14 @@ const start_server = function ({ context_meta, config, jsbuild_app_frontend }) {
 					console.warn(['Unexpected: ws_map missing uid', ws.data.uid])
 				}
 				else {
+					// stop ping-ing
+					if (map_obj.id_interval_ping !== null) {
+						clearInterval(map_obj.id_interval_ping)
+					}
+					// stop pong-check-ing
+					if (map_obj.id_timeout_checkpong !== null) {
+						clearTimeout(map_obj.id_timeout_checkpong)
+					}
 					if (map_obj.closed_by_server === true) {
 						console.info(['ws closed by server', ws.data.uid])
 						// cleanup will happen in outer context
@@ -96,6 +145,22 @@ const start_server = function ({ context_meta, config, jsbuild_app_frontend }) {
 				return
 			},
 			message: function (ws, message) {},
+			pong: function (ws, data) {
+				//console.debug(['ws pong', ws.data.uid])
+				const map_obj = context_meta.ws_map.get(ws.data.uid)
+				if (map_obj === undefined) {
+					console.warn(['Unexpected: ws_map missing uid', ws.data.uid])
+				}
+				else {
+					// cancel pending check
+					if (map_obj.id_timeout_checkpong !== null) {
+						clearTimeout(map_obj.id_timeout_checkpong)
+						// reset this for future ref
+						map_obj.id_timeout_checkpong = null
+					}
+				}
+				return
+			},
 		},
 	})
 	return server
@@ -120,10 +185,19 @@ const async_run = async function ({
 	config,
 	jsbuild_app_frontend,
 }) {
+	const active_config = {
+		// defaults
+		hostname: '127.0.0.1',
+		port: 8800,
+		ping_interval: 1000 * 15,
+		pong_timeout : 1000 * 5,
+		// overrides
+		...config,
+	}
 	const context_meta = {
 		ws_map: new Map(),
 	}
-	const server = start_server({ context_meta, config, jsbuild_app_frontend })
+	const server = start_server({ context_meta, config: active_config, jsbuild_app_frontend })
 	console.info(server)
 	process.on('SIGINT', async () => {
 		console.log('SIGINT intercepted')