Shopping cart for TrinteJS framework

cart.js

/**
 *  Shopping Cart manager
 *  
 *
 *  Created by init script
 *  App based on TrinteJS MVC framework
 *  TrinteJS homepage http://www.trintejs.com
 **/

exports.addProductToCart = function addProductToCart() {
    return function(req, res, next) {
        var newProduct = req.body.product;
        if (newProduct) {
            if (req.session) {
                if (!req.session.cart) {
                    req.session.cart = {
                        sum_total: 0,
                        products: []
                    };
                }
                var found = false, products = [], sum_total = 0;
                req.session.cart.products.forEach(function(product) {
                    if (newProduct.id === product.id) {
                        product.qty = (product.qty + newProduct.qty);
                        products.push(product);
                        found = true;
                    }
                    sum_total = sum_total + (product.qty * product.price);
                });
                if (!found) {
                    products.push(newProduct);
                    sum_total = sum_total + (newProduct.qty * newProduct.price);
                }
                req.session.cart.products = products;
                req.session.cart.sum_total = sum_total;
                res.locals({
                    cart: req.session.cart
                });
                res.send('Product added!');
            }
        } else {
            res.send('Invalid product!');
        }
    };
};

exports.getProductFromCart = function getProductFromCart() {
    return function(req, res, next) {
        if (!req.session) {
            req.session = {};
        }
        if (!req.session.cart) {
            req.session.cart = {
                sum_total: 0,
                products: []
            };
        }
        res.send({
            cart: req.session.cart
        });
    };
};