Store cart in the DB and handle the holding of stock across sessions

app.js

@@ -5,11 +5,13 @@ const cookieParser = require('cookie-parser');
 const bodyParser = require('body-parser');
 const session = require('express-session');
 const moment = require('moment');
+const _ = require('lodash');
 const MongoStore = require('connect-mongodb-session')(session);
 const MongoClient = require('mongodb').MongoClient;
 const numeral = require('numeral');
 const helmet = require('helmet');
 const colors = require('colors');
+const cron = require('node-cron');
 const common = require('./lib/common');
 const mongodbUri = require('mongodb-uri');
 let handlebars = require('express-handlebars');
@@ -234,7 +236,7 @@ app.use(session({
     cookie: {
         path: '/',
         httpOnly: true,
-        maxAge: 3600000 * 24
+        maxAge: 900000
     },
     store: store
 }));
@@ -346,6 +348,8 @@ MongoClient.connect(config.databaseConnectionString, {}, (err, client) => {
     db.pages = db.collection('pages');
     db.menu = db.collection('menu');
     db.customers = db.collection('customers');
+    db.cart = db.collection('cart');
+    db.sessions = db.collection('sessions');
 
     // add db to app for routes
     app.dbClient = client;
@@ -353,6 +357,20 @@ MongoClient.connect(config.databaseConnectionString, {}, (err, client) => {
     app.config = config;
     app.port = app.get('port');
 
+    // Fire up the cron job to clear temp held stock
+    cron.schedule('*/1 * * * *', async () => {
+        const validSessions = await db.sessions.find({}).toArray();
+        const validSessionIds = [];
+        _.forEach(validSessions, (value) => {
+            validSessionIds.push(value._id);
+        });
+
+        // Remove any invalid cart holds
+        await db.cart.remove({
+            sessionId: {$nin: validSessionIds}
+        });
+    });
+
     // run indexing
     common.runIndexing(app)
     .then(app.listen(app.get('port')))

routes/index.js

@@ -4,6 +4,7 @@ const colors = require('colors');
 const async = require('async');
 const _ = require('lodash');
 const common = require('../lib/common');
+const ObjectId = require('mongodb').ObjectID;
 
 // These is the customer facing routes
 router.get('/payment/:orderId', async (req, res, next) => {
@@ -207,10 +208,15 @@ router.post('/product/updatecart', (req, res, next) => {
                 }
             });
         }
-    }, () => {
+    }, async () => {
         // update total cart amount
         common.updateTotalCartAmount(req, res);
 
+        // Update cart to the DB
+        await db.cart.update({sessionId: req.session.id}, {
+            $set: {cart: req.session.cart}
+        });
+
         // show response
         if(hasError === false){
             res.status(200).json({message: 'Cart successfully updated', totalCartItems: Object.keys(req.session.cart).length});
@@ -226,6 +232,8 @@ router.post('/product/updatecart', (req, res, next) => {
 
 // Remove single product from cart
 router.post('/product/removefromcart', (req, res, next) => {
+    const db = req.app.db;
+
     // remove item from cart
     async.each(req.session.cart, (item, callback) => {
         if(item){
@@ -234,7 +242,11 @@ router.post('/product/removefromcart', (req, res, next) => {
             }
         }
         callback();
-    }, () => {
+    }, async () => {
+        // Update cart in DB
+        await db.cart.update({sessionId: req.session.id}, {
+            $set: {cart: req.session.cart}
+        });
         // update total cart amount
         common.updateTotalCartAmount(req, res);
         res.status(200).json({message: 'Product successfully removed', totalCartItems: Object.keys(req.session.cart).length});
@@ -242,10 +254,16 @@ router.post('/product/removefromcart', (req, res, next) => {
 });
 
 // Totally empty the cart
-router.post('/product/emptycart', (req, res, next) => {
+router.post('/product/emptycart', async (req, res, next) => {
+    const db = req.app.db;
+
+    // Remove from session
     delete req.session.cart;
     delete req.session.orderId;
 
+    // Remove cart from DB
+    await db.cart.removeOne({sessionId: req.session.id});
+
     // update total cart amount
     common.updateTotalCartAmount(req, res);
     res.status(200).json({message: 'Cart successfully emptied', totalCartItems: 0});
@@ -269,7 +287,7 @@ router.post('/product/addtocart', (req, res, next) => {
     }
 
     // Get the item from the DB
-    db.products.findOne({_id: common.getId(req.body.productId)}, (err, product) => {
+    db.products.findOne({_id: common.getId(req.body.productId)}, async (err, product) => {
         if(err){
             console.error(colors.red('Error adding to cart', err));
             return res.status(400).json({message: 'Error updating cart. Please try again.'});
@@ -281,11 +299,38 @@ router.post('/product/addtocart', (req, res, next) => {
         }
 
         // If stock management on check there is sufficient stock for this product
-        if(config.trackStock){
+        if(config.trackStock && product.productStock){
-            if(productQuantity > product.productStock){
+            const stockHeld = await db.cart.aggregate(
+                {
+                    $match: {
+                        cart: {$elemMatch: {productId: product._id.toString()}}
+                    }
+                },
+                {$unwind: '$cart'},
+                {
+                    $group: {
+                        _id: '$cart.productId',
+                        sumHeld: {$sum: '$cart.quantity'}
+                    }
+                },
+                {
+                    $project: {
+                        sumHeld: 1
+                    }
+                }
+            ).toArray();
+
+            // If there is stock
+            if(stockHeld.length > 0){
+                const totalHeld = _.find(stockHeld, {_id: product._id.toString()}).sumHeld;
+                const netStock = product.productStock - totalHeld;
+
+                // Check there is sufficient stock
+                if(productQuantity > netStock){
                     return res.status(400).json({message: 'There is insufficient stock of this product.'});
                 }
             }
+        }
 
         let productPrice = parseFloat(product.productPrice).toFixed(2);
 
@@ -301,13 +346,18 @@ router.post('/product/addtocart', (req, res, next) => {
 
         // if exists we add to the existing value
         let cartIndex = _.findIndex(req.session.cart, findDoc);
+        let cartQuantity = 0;
         if(cartIndex > -1){
-            req.session.cart[cartIndex].quantity = parseInt(req.session.cart[cartIndex].quantity) + productQuantity;
+            cartQuantity = parseInt(req.session.cart[cartIndex].quantity) + productQuantity;
+            req.session.cart[cartIndex].quantity = cartQuantity;
             req.session.cart[cartIndex].totalItemPrice = productPrice * parseInt(req.session.cart[cartIndex].quantity);
         }else{
             // Doesnt exist so we add to the cart session
             req.session.cartTotalItems = req.session.cartTotalItems + productQuantity;
 
+            // Set the card quantity
+            cartQuantity = productQuantity;
+
             // new product deets
             let productObj = {};
             productObj.productId = req.body.productId;
@@ -327,6 +377,11 @@ router.post('/product/addtocart', (req, res, next) => {
             req.session.cart.push(productObj);
         }
 
+        // Update cart to the DB
+        await db.cart.update({sessionId: req.session.id}, {
+            $set: {cart: req.session.cart}
+        }, {upsert: true});
+
         // update total cart amount
         common.updateTotalCartAmount(req, res);