Create central-server.js

Author: angrycoding

central-server.js

@@ -0,0 +1,100 @@
+const Express = require('express');
+
+var server = Express();
+server.listen(1338, '0.0.0.0');
+
+const MAX_ELEMENTS_PER_IP = 10;
+const MAX_TIME_TO_KEEP_MS = 1000 * 60 * 3;
+const CLEANUP_INTERVAL_MS = 1000 * 60 * 1;
+
+server.use(Express.json({
+	strict: false,
+	type: 'application/x-www-form-urlencoded'
+}));
+
+const respondWithJSON = (request, response, data) => {
+	if (arguments.length < 3) data = 0;
+	response.header('Access-Control-Allow-Origin', '*');
+	response.end(JSON.stringify(data));
+};
+
+const mappingTable = {
+
+}
+
+server.post('/getHosts', (request, response) => {
+	
+	// const remoteAddress = request.socket.remoteAddress;
+	// if (typeof remoteAddress !== 'string' || !remoteAddress) return respondWithJSON(request, response);
+
+	const browserId = request.body.browserId;
+	if (typeof browserId !== 'string' || !browserId) return;
+	
+
+	if (!mappingTable.hasOwnProperty(browserId)) return respondWithJSON(request, response);
+	if (!mappingTable[browserId].length) return respondWithJSON(request, response);
+	respondWithJSON(request, response, mappingTable[browserId].map(x => x.deviceIp));
+});
+
+server.post('/retropie', (request, response) => {
+	response.end();
+
+
+	console.info(request.socket.remoteAddress, request.socket.remotePort)
+	
+
+	const browserId = request.body.browserId;
+	if (typeof browserId !== 'string' || !browserId) return;
+
+	const deviceIp = request.body.deviceIp;
+	if (typeof deviceIp !== 'string' || !deviceIp) return;
+
+
+	const addresses = (
+		mappingTable.hasOwnProperty(browserId) ?
+		mappingTable[browserId] :
+		mappingTable[browserId] = []
+	);
+
+
+	const existingIndex = addresses.findIndex(item => item.deviceIp === deviceIp);
+	const when = Date.now();
+	
+	if (existingIndex !== -1) {
+		const existingAddress = addresses[existingIndex];
+		addresses.splice(existingIndex, 1);
+		addresses.push({ ...existingAddress, when });
+	} else {
+		addresses.push({ when, deviceIp });
+	}
+
+	mappingTable[browserId] = addresses.slice(-MAX_ELEMENTS_PER_IP);
+
+	
+});
+
+
+const checkExpiredAddresses = () => {
+	console.info('checkExpiredAddresses:start');
+	for (const browserId in mappingTable) {
+		
+		mappingTable[browserId] = mappingTable[browserId].filter(address => {
+			const isExpired = (Date.now() - address.when >= MAX_TIME_TO_KEEP_MS);
+			if (isExpired) console.info(`expired ${browserId} -> ${JSON.stringify(address)}`);
+			return !isExpired;
+		});
+
+		if (!mappingTable[browserId].length) {
+			console.info(`remove ${browserId} from table`);
+			delete mappingTable[browserId];
+		}
+
+	}
+
+	console.info('checkExpiredAddresses:finish');
+	setTimeout(checkExpiredAddresses, CLEANUP_INTERVAL_MS);
+
+};
+
+
+checkExpiredAddresses();