Fixed bugs; Removed caching that would cause problems with spinning up multiple processes.

app.js

@@ -10,12 +10,14 @@ var pingRouter = require('./routes/ping');
 var app = express();
 
 let port = 3003;
+let log = false;
 
 if(process.env.PORT) port = process.env.PORT;
+if(process.env.LOG) log = process.env.LOG;
 
 console.log("Running on port: " + port);
 
-app.use(logger('dev'));
+if(log) app.use(logger('dev'));
 app.use(express.json());
 app.use(express.urlencoded({ extended: false }));
 app.use(cookieParser());

routes/ping.js

@@ -13,7 +13,6 @@ if(!uri) {
 }
 const client = new MongoClient(uri);
 let collection;
-let records = {};
 
 // We are keeping an in-memory set of current/active records for each Chromebook to reduce the number of reads without _id we perform.
 // The idea is that each Chromebook pings every 5 minutes when a student is logged in and using the Chromebook.
@@ -26,29 +25,16 @@ async function connect() {
 		await client.connect();
 		const database = client.db("avusd_data_collection");
 		collection = database.collection('records');
-		console.log("Connected to Mongodb server");
+		// console.log("Connected to Mongodb server");
 	} catch(e) {
+		console.log("error: caught ping.js:31 in Data Collection.");
 		console.log(e);
 	}
 }
 
-// Load a record for specific Chromebook by serial number (we assume they are unique).
-async function loadRecord(serial) {
-	//Read record with given serial.
-	let record = await collection.findOne({serial, closed: false});
-
-	//If we found one then add it to the map.
-	if(record && !record.closed) {
-		records[record.serial] = record;
-	}
-	else {record = null;}
-
-	return record;
-}
-
 // Create a new record for a Chromebook & user.  Set it in the cache (replace any existing one for that serial).
 async function createRecord(record, isInternal) {
-	record.startTime = new Date().getTime();
+	record.startTime = record.endTime = new Date().getTime();
 	record.count = 1;
 	record.internalCount = isInternal ? 1 : 0;
 
@@ -57,75 +43,35 @@ async function createRecord(record, isInternal) {
 
 	//Handle errors.
 	if(queryResult.writeConcernError && queryResult.writeConcernError.errmsg) {
+		console.log("error: caught ping.js:61 in Data Collection.");
 		console.log(queryResult.writeConcernError.errmsg + " ::: " + JSON.stringify(record));
-		record = null;
 	}
-	else {
-		//Add the map if there were no errors.
-		records[record.serial] = record;
-	}
-
-	return record;
 }
 
-// Update a record.  Will create a new record if one doesn't exist for the Chromebook.  Will close a record if the user changes, and then create a new one for the new user.
 async function updateRecord(record, isInternal, clientAddress) {
-	let existing = records[record.serial];
+	try {
-
 		if(!collection) {
 			await connect();
 		}
 
-	//If one is not in the cache, then read it from the db.
+		//Read record with given serial.
-	if(!existing) {
+		let existing = await collection.findOne({serial: record.serial, closed: {$exists: false}});
-		existing = await loadRecord(record.serial);
-	}
 
-	//If we couldn't find one for the given serial in the db, then create it.
-	// Note: We only do this if the connection is on the internal network.
-	// This prevents attackers from spamming the server with random id's to pollute the data.
 		if(!existing) {
-		if(isInternal) {
-			existing = await createRecord(record, isInternal);
-		}
-		else {
-			//Log the external attempt to update a 'new' chromebook.
-			console.log("Ignoring external (" + clientAddress + ") input: " + JSON.stringify(record));
-		}
-	}
-	else {
-		let changed = {};
-		let inc = {};
-
-		//If the user has changed, then close the record.  Create a new record for the new user.
-		if(existing.email !== record.email) {
-			changed.closed = existing.closed = true;
 			await createRecord(record, isInternal);
 		}
 		else {
-			//Update the time and count for both the db and the in memory data.
+			//If the user has changed, then close the record.  Create a new record for the new user.
-			changed.endTimestamp = existing.endTimestamp = new Date().getTime();
+			if(existing.email !== record.email) {
-			// Note: Cannot increment this way because there could be multiple instances of this process running with different cached values.  Use MongoDB $inc instead.
+				await collection.updateOne({_id: existing._id}, {$set: {closed: true}});
-			// changed.count = existing.count = existing.count + 1;
+				await createRecord(record, isInternal);
-			inc.count = 1;
+			}
-
+			else {
-			//Update the internal count if the Chromebook address is on the internal network.
+				await collection.updateOne({_id: existing._id}, {$set: {endTime: new Date().getTime()}, $inc: {count: 1, internalCount: isInternal ? 1 : 0}});
-			if(isInternal) {
-				// Note: Cannot increment this way because there could be multiple instances of this process running with different cached values.  Use MongoDB $inc instead.
-				// changed.internalCount = existing.internalCount = existing.internalCount + 1;
-				inc.internalCount = 1;
-			}
-		}
-
-		//If something changed, then update the db.
-		if(!_.isEmpty(changed)) {
-			let result = await collection.updateOne({_id: existing._id}, {$set: changed, $inc: inc});
-
-			//Error handling.
-			if(result.modifiedCount !== 1) {
-				console.log("Failed to update the record: " + JSON.stringify(existing));
 			}
 		}
+	} catch(e) {
+		console.log(e);
 	}
 }
 
@@ -144,14 +90,16 @@ router.get('/', function(req, res, next) {
 	// console.log("Serial: " + params.serial);
 	// console.log("DeviceId: " + params.deviceId);
 
+	// Ignore any calls without a serial.
+	if(params.serial) {
 		let clientAddress = req.header("X-Real-IP");
-	if(!clientAddress) clientAddress = req.socket.remoteAddress;
+		if (!clientAddress) clientAddress = req.socket.remoteAddress;
 		let isLocal = true;
-	console.log("Found IP: " + clientAddress);
+		// console.log("Found IP: " + clientAddress);
 
-	if(localAddresses) {
+		if (localAddresses) {
 			isLocal = false;
-		for(let i = 0; !isLocal && i < localAddresses.length; i++) {
+			for (let i = 0; !isLocal && i < localAddresses.length; i++) {
 				let next = localAddresses[i];
 				isLocal = clientAddress.startsWith(next);
 			}
@@ -159,6 +107,7 @@ router.get('/', function(req, res, next) {
 
 		//Note: We are not waiting for this to finish.  We don't care about the output.
 		updateRecord({serial, assetId, deviceId, email}, isLocal, clientAddress);
+	}
 
 	//Send response.  Nothing for the moment.
 	res.setHeader("Access-Control-Allow-Origin", "*");