Added all db write methods to a queue.

Should resolve DB busy crash.

index.js

@@ -4,6 +4,9 @@ var http = require('http');
 // Create a service (the app object is just a callback).
 var app = express();
 
+//used to prevent database is busy errors
+var writeQueue = require('./writeQueue');
+
 //hashing service
 var crypto = require('crypto');
 
@@ -196,7 +199,8 @@ app.get('/api/postVideoSponsorTimes', async function (req, res) {
         
                         if (row == null) {
                             //not a duplicate, execute query
-                            db.prepare("INSERT INTO sponsorTimes VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?)").run(videoID, startTime, endTime, startingVotes, UUID, userID, timeSubmitted, 0, shadowBanned, function (err) {
+                            let preparedStatement = db.prepare("INSERT INTO sponsorTimes VALUES(?, ?, ?, ?, ?, ?, ?, ?, ?)");
+                            let callback = function (err) {
                                 if (err) {
                                     //a DB change probably occurred, respond as if it is a duplicate
                                     res.sendStatus(409);
@@ -204,11 +208,14 @@ app.get('/api/postVideoSponsorTimes', async function (req, res) {
                                     console.log("Error when putting sponsorTime in the DB: " + videoID + ", " + startTime + ", " + "endTime" + ", " + userID);
                                 } else {
                                     //add to private db as well
-                                    privateDB.prepare("INSERT INTO sponsorTimes VALUES(?, ?, ?)").run(videoID, hashedIP, timeSubmitted);
+                                    writeQueue.addToWriteQueue(new writeQueue.WriteQueue(privateDB.prepare("INSERT INTO sponsorTimes VALUES(?, ?, ?)")), [videoID, hashedIP, timeSubmitted]);
 
                                     res.sendStatus(200);
                                 }
-                            });
+                            };
+
+                            writeQueue.addToWriteQueue(new writeQueue.WriteQueue(preparedStatement, [videoID, startTime, endTime, startingVotes, UUID, userID, timeSubmitted, 0, shadowBanned], callback));
+                            
                         } else {
                             res.sendStatus(409);
                         }
@@ -304,7 +311,7 @@ app.get('/api/voteOnSponsorTime', function (req, res) {
             if (votesRow != undefined) {
                 privateDB.prepare("UPDATE votes SET type = ? WHERE userID = ? AND UUID = ?").run(type, userID, UUID);
             } else {
-                privateDB.prepare("INSERT INTO votes VALUES(?, ?, ?, ?)").run(UUID, userID, hashedIP, type);
+                writeQueue.addToWriteQueue(new writeQueue.WriteQueue(privateDB.prepare("INSERT INTO votes VALUES(?, ?, ?, ?)")), [UUID, userID, hashedIP, type]);
             }
 
             //update the vote count on this sponsorTime
@@ -393,7 +400,7 @@ app.post('/api/setUsername', function (req, res) {
             db.prepare("UPDATE userNames SET userName = ? WHERE userID = ?").run(userName, userID);
         } else {
             //add to the db
-            db.prepare("INSERT INTO userNames VALUES(?, ?)").run(userID, userName);
+            writeQueue.addToWriteQueue(new writeQueue.WriteQueue(db.prepare("INSERT INTO userNames VALUES(?, ?)")), [userID, userName]);
         }
 
         res.sendStatus(200);
@@ -473,7 +480,7 @@ app.post('/api/shadowBanUser', async function (req, res) {
         //add them to the shadow ban list
 
         //add it to the table
-        privateDB.prepare("INSERT INTO shadowBannedUsers VALUES(?)").run(userID);
+        writeQueue.addToWriteQueue(new writeQueue.WriteQueue(privateDB.prepare("INSERT INTO shadowBannedUsers VALUES(?)")), [userID]);
 
         //find all previous submissions and hide them
         db.prepare("UPDATE sponsorTimes SET shadowHidden = 1 WHERE userID = ?").run(userID);
@@ -524,7 +531,7 @@ app.post('/api/addUserAsVIP', async function (req, res) {
 
     if (enabled && result.row.userCount == 0) {
         //add them to the vip list
-        db.prepare("INSERT INTO vipUsers VALUES(?)").run(userID);
+        writeQueue.addToWriteQueue(new writeQueue.WriteQueue(db.prepare("INSERT INTO vipUsers VALUES(?)")), [userID]);
     } else if (!enabled && result.row.userCount > 0) {
         //remove them from the shadow ban list
         db.prepare("DELETE FROM vipUsers WHERE userID = ?").run(userID);

writeQueue.js

@@ -0,0 +1,69 @@
+'use strict';
+
+//used to queue objects to be written to the db
+class WriteQueue {
+    /**
+     * @param {Statement} statement 
+     * @param {Array} inputs 
+     * @param {callback} callback
+     */
+    constructor(statement, inputs, callback) {
+        this.statement = statement;
+        this.inputs = inputs;
+        this.callback = callback;
+    }
+
+    run() {
+        return new Promise((resolve, reject) => {
+            this.statement.run(this.inputs, (err) => this.end(err, resolve, reject));
+        });
+    }
+
+    end(err, resolve, reject) {
+        resolve();
+
+        if (this.callback) {
+            this.callback(err);
+        }
+    }
+}
+
+module.exports = {
+    WriteQueue,
+    addToWriteQueue
+}
+
+/**
+ * Array of class write queue
+ * 
+ * @typedef WriteQueue[]
+ */
+var dbQueue = [];
+
+//is a queue check currently running
+var queueRunning = false;
+
+/**
+ * Adds an item to the write queue and starts the run function if needed.
+ * 
+ * @param {WriteQueue} item 
+ */
+function addToWriteQueue(item) {
+    dbQueue.push(item);
+
+    if (!queueRunning) {
+        runThroughWriteQueue();
+    }
+}
+
+async function runThroughWriteQueue() {
+    queueRunning = true;
+
+    while (dbQueue.length > 0) {
+        await dbQueue[0].run();
+
+        dbQueue.splice(0, 1);
+    }
+
+    queueRunning = false;
+}