app.js

/*it2022134 Exarchou Athos, mark: 9.4625*/

const express = require('express');
const app = express();
const parser = require('body-parser');
const sqlite3 = require('sqlite3').verbose();
const db = new sqlite3.Database('books.sqlite');

app.use(express.static('public'));
app.use(parser.json());

db.serialize(() => { /* creates a new table in the database, in case the old database table was deleted */
    db.run("CREATE TABLE IF NOT EXISTS books (id INTEGER PRIMARY KEY AUTOINCREMENT," +
            "author VARCHAR(25) NOT NULL, title VARCHAR(40) NOT NULL, genre VARCHAR(20) NOT NULL, price REAL NOT NULL);");
});

app.get('/books/:keyword', function(req,res) {

    const keyword = req.params.keyword;
    const query = `SELECT * FROM books WHERE (title LIKE "%${keyword}%")`; /* displays the book(s) that match the given keyword */

    db.all(query, (err,results) => {

        /* displays the result, whether that is an error or not */
        if (err) {
            res.status(500);
            res.send({'Error':'Internal server error'});
            console.error(err);
        } else {
            if (results.length == 0) {
                res.status(404);
                res.send({'Error':'Book not found'});
                console.error(err);
            } else {
                res.json(results);
            }
        }
    });
});

app.post('/books', function(req, res) {

    const book = req.body;
    /* adds a new book to the table according to the user's input data */
    const query = `INSERT INTO books (author, title, genre, price) VALUES (?, ?, ?, ?)`;
    db.run(query, [book.author, book.title, book.genre, book.price], (err) => {

        /* displays the result, whether that is an error or not */
        if (err) {
            res.status(500);
            res.send({'Error':'Internal server error'});
            console.error(err);
        } else {
            res.json({'Result':'Book added successfully!'});
        }
    });
});

/* opens the server at localhost:3000 */
app.listen(3000, function() {
    console.log('Initiating server at: http://localhost:3000');
});