Merge branch 'main' of https://github.com/shalabh147/Database-Systems…

…-Assignments

Lab5-Nodejs/README.md

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+# Online store web app using node.js express framework and postgresql database
+
+* routing get and post requests to controller
+* querying database in model (Standard MVC arch)
+
+## Requirements
+1. Node.js
+2. node modules installation through npm

Lab5-Nodejs/app.js

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+
+const express = require('express');
+const path = require('path');
+const bodyParser = require('body-parser');
+
+const adminRo = require('./routes/admin');
+const nonadminRo = require('./routes/nonadmin');
+const pool =  require('./utils/database');
+
+
+const app = express();
+app.set('view engine', 'ejs');
+app.set('views', 'views');
+app.use(bodyParser.urlencoded({ extended:true}));
+app.use(express.static(path.join(__dirname,'public')));
+
+
+app.use('/admin',adminRo);
+app.use('/',nonadminRo);
+
+
+app.listen(3000);

Lab5-Nodejs/controllers/admin.js

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+const Prod = require('../models/prod');
+
+
+exports.get_test = (req,res,next) => {
+
+
+    res.render('admin/add_product', {
+        pageTitle: 'Add Product',
+        path: '/admin/add-product',
+        editing: false
+    });
+
+
+};
+
+exports.post_test = (req,res,next) => {
+    const title = req.body.title;
+    const image = req.body.image;
+    const price = req.body.price;
+    const quantity = req.body.quantity;
+    const product = new Prod( title, image, price,quantity);
+    product
+        .add_prod()
+        .then(() => {
+            res.redirect('/admin/add-product');
+        })
+        .catch(err => console.log(err));
+};
+
+
+exports.get_prods_test = (req,res,next) => {
+
+    const a = Prod.get_all();
+    a.then(value => {res.render('prods', {pageTitle: 'Products', path: '/prods', editing: false, articles:value.rows});});
+
+
+
+};
+
+exports.post_prods_test = (req,res,next) => {
+    //    .catch(err => console.log(err));
+};
+
+
+
+
+exports.get_cart_test = (req,res,next) => {
+
+    const a = Prod.get_all_cart();
+    var x;
+    const b = Prod.get_credit();
+
+    a.then(value => {x = value; return Prod.get_credit();})
+    .then(val => {res.render('cart', {pageTitle: 'Cart', path: '/cart', editing: false, articles:x.rows, count: x.rowCount, cred: val.rows[0].credit });});
+
+
+};
+
+exports.post_cart_test = (req,res,next) => {
+
+    const product_id = req.body.product_id;
+
+
+    const nice = Prod.get_with_prod_id(product_id);
+    nice.then(val => {if(val.rowCount != 0) 
+        {return Prod.get_in_cart_id(product_id).then(value => {Prod.update_in_prod(product_id); if(value.rowCount != 0) {return Prod.update_in_cart(product_id)} else return Prod.insert_in_cart(product_id)})
+    .then(() => {return res.redirect('/cart')}); } 
+    else {return res.redirect('/prods')}});
+
+};
+
+
+
+exports.get_orders_test = (req,res,next) => {
+
+    const ord = Prod.get_all_orders();
+    ord.then(value => {res.render('orders', {pageTitle: 'Orders', path: '/orders', editing: false, articles:value.rows});});
+
+
+
+};
+
+exports.post_orders_test = (req,res,next) => {
+
+    const cred = Prod.remcred();
+    var x,y;
+    var pur;
+    var pro_list = [];
+    var res_list = [];
+    var id_list = [];
+    var newlist = [];
+
+    cred.then(val => { x = val.rows[0].credit; return Prod.sum_price_cart()})
+        .then(value => {if(x < value.rows[0].sum) {return res.redirect('/cart') } 
+        else {pur = value.rows[0].sum; return Prod.get_full_cart().then(ui => {y = ui.rowCount;
+            //  console.log(y);
+          for (i = 0; i < y; i++) {
+          var id = ui.rows[i].item_id;
+          id_list.push(id);
+          pro_list.push(Prod.present_in_orders(id))} return Promise.all(pro_list)} )
+          .then(chec => {
+              for (i = 0; i < chec.length; i++) {
+
+                  if(chec[i].rowCount == 0)
+                  {//   console.log("id"+id_list[i]);
+                      newlist.push(Prod.insert_order(id_list[i]));
+                  }
+                  else
+                  {  // console.log("id"+id_list[i]);
+                      newlist.push(Prod.update_order(id_list[i]));
+                  }
+              }
+
+              return Promise.all(newlist);
+
+          })
+          .then(()=>{return Prod.empty_cart()})
+          .then(() => {return Prod.update_credit(pur)})
+          .then(()=>{res.redirect('/orders')});}})    
+
+
+
+
+
+};
+
+

Lab5-Nodejs/models/prod.js

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+
+const pool= require('../utils/database');
+module.exports = class Prod{
+
+    constructor( title, image, price, quantity){
+        this.title = title;
+        this.image = image;
+        this.price = price;
+        this.quantity = quantity;
+    }
+
+    add_prod(){
+        return pool.query('INSERT INTO products(title, price, image, quantity) VALUES ($1, $2, $3, $4);', [this.title, this.price, this.image, this.quantity]);
+    }
+
+/*    add_prod_to_cart(){
+        return pool.query('INSERT INTO cart(user_id, item_id, quantity) VALUES ($1, $2, $3);', [this.userid, this.itemid, this.quantity]);
+    }
+*/
+    static get_all_cart()
+    {
+        return pool.query('SELECT u.credit,p.title,p.price,c.quantity,p.image from users u,products p,cart c where u.user_id = c.user_id and p.id = c.item_id');
+    }
+
+    static get_with_prod_id(prod_id)
+    {
+        const f = pool.query('SELECT * from products p where p.id = $1 and p.quantity > 0;',[prod_id]);
+        return f;
+        //f.then(value => {console.log(value.rowCount)});
+        //return f.then(value => {if(value.rowCount == 0) return false; else return true; });
+    }
+    static get_in_cart_id(prod_id)
+    {   //f.then(value => {console.log(value.rowCount)});
+        return pool.query('SELECT * from cart c where c.item_id = $1;',[prod_id]);
+        //return f.then(value => {if(value.rowCount == 0) return false; else return true; });
+
+    }
+
+    static update_in_cart(prod_id)
+    {
+        return pool.query('UPDATE cart c set quantity = quantity + 1 where c.item_id = $1;',[prod_id]);
+    }
+
+    static update_in_prod(prod_id)
+    {
+        return pool.query('UPDATE products p set quantity = quantity-1 where p.id = $1;',[prod_id]);
+    }
+
+    static insert_in_cart(prod_id)
+    {
+        return pool.query('INSERT INTO cart(user_id,item_id,quantity) VALUES ($1,$2,$3);', [1,prod_id,1]);
+    }
+
+    static get_all_orders(prod_id)
+    {
+        return pool.query('SELECT u.credit,p.title,p.price,o.quantity,p.image from users u,products p,orders o where u.user_id = o.user_id and p.id = o.item_id');
+    }
+
+    static remcred()
+    {
+        return pool.query('SELECT credit from users');
+    }
+
+    static sum_price_cart()
+    {
+        return pool.query('SELECT sum(p.price*c.quantity) as sum from cart c, products p where p.id = c.item_id;')
+    }
+
+    static empty_cart()
+    {
+        return pool.query('DELETE FROM cart;')
+    }
+
+    static buy_all()
+    {
+        return pool.query('INSERT INTO orders SELECT * FROM CART ')
+    }
+
+    static update_credit(amount)
+    {
+        return pool.query('UPDATE users set credit = credit - $1;',[amount])
+    }
+
+    static get_full_cart()
+    {
+        return pool.query('SELECT * from cart;')
+    }
+
+    static get_full_cred(id)
+    {
+        return pool.query('SELECT * FROM CART WHERE item_id = id;')
+    }
+
+    static update_order(id)
+    {
+        return pool.query('update orders set quantity = orders.quantity+c.quantity from cart c where orders.item_id = $1 and orders.item_id = c.item_id',[id])
+    }
+
+    static insert_order(id)
+    {
+        return pool.query('insert into orders (select * from cart where item_id = $1)',[id])
+    }
+
+    static present_in_orders(id)
+    {
+        return pool.query('SELECT * FROM orders where item_id = $1;',[id])
+    }
+
+    static get_credit()
+    {
+        return pool.query('SELECT * FROM users;')
+    }
+
+    static get_all(){
+        return pool.query('SELECT * FROM products');
+
+    }
+
+};