app.js

const path = require('path');
const express = require('express');
const morgan = require('morgan');

const app = express();
app.set('trust proxy', 1);


const rateLimit = require('express-rate-limit');
const helmet = require('helmet');
const mongoSanitize = require('express-mongo-sanitize');
const xss = require('xss-clean');
const hpp = require('hpp');

const cookieParser = require('cookie-parser');
const compression = require('compression');
const AppError = require('./utils/appError');
const globalErrorHandler = require('./controllers/errorController');
const tourRouter = require('./routes/tourRoutes');
const userRouter = require('./routes/userRoutes');
const reviewRouter = require('./routes/reviewRoutes');
const viewRouter = require('./routes/viewRoutes');
const bookingRouter = require('./routes/bookingRoutes');


app.set('view engine', 'pug');
app.set('views', path.join(__dirname, 'views'));

// GLOBAL MIDDLEWARE
// SERVING STATIC FILES
app.use(express.static(path.join(__dirname, 'public')));

// Further HELMET configuration for Security Policy (CSP)
const scriptSrcUrls = [
    'https://unpkg.com/',
    'https://tile.openstreetmap.org',
    'https://js.stripe.com',
    'https://m.stripe.network',
    'https://*.cloudflare.com',
];
const styleSrcUrls = [
    'https://unpkg.com/',
    'https://tile.openstreetmap.org',
    'https://fonts.googleapis.com/',
];
const connectSrcUrls = [
    'https://unpkg.com',
    'https://tile.openstreetmap.org',
    'https://*.cloudflare.com/',
    'https://bundle.js:*',
    'ws://127.0.0.1:*/',
    'ws://localhost:*/',
];
const fontSrcUrls = ['fonts.googleapis.com', 'fonts.gstatic.com'];

// Helmet is a collection of middleware functions that help secure your Express apps by setting various HTTP headers
//set security http headers
app.use(
    helmet.contentSecurityPolicy({
        directives: {
            defaultSrc: [],
            connectSrc: ["'self'", ...connectSrcUrls],
            scriptSrc: ["'self'", ...scriptSrcUrls],
            styleSrc: ["'self'", "'unsafe-inline'", ...styleSrcUrls],
            workerSrc: ["'self'", 'blob:'],
            objectSrc: [],
            imgSrc: ["'self'", 'blob:', 'data:', 'https:'],
            fontSrc: ["'self'", ...fontSrcUrls],
        },
    }),
);

// Development logging
if (process.env.NODE_ENV === 'development') {
    app.use(morgan('dev'));
}

app.use((req, res, next) => {
    req.requestTime = new Date().toISOString();
    next();
});

const limiter = rateLimit({
    max: 100,
    windowMs: 60 * 60 * 1000,
    message: 'Too many requests from this IP, please try again in an hour!',
});
app.use('/api', limiter);

// BODY PARSER is used for reading data from body into req.body
app.use(express.json({ limit: '10kb' }));
app.use(express.urlencoded({ extended: true, limit: '10kb' }));
app.use(cookieParser());

// DATA SANITIZATION against NoSQL query injection
app.use(mongoSanitize());

// DATA SANITIZATION against XSS
app.use(xss());

// PREVENT PARAMETER POLLUTION
app.use(
    hpp({
        whitelist: [
            'duration',
            'ratingsAverage',
            'ratingsQuantity',
            'maxGroupSize',
            'difficulty',
            'price',
        ],
    }),
);

app.use(compression());

// ROUTES
app.use('/', viewRouter);
app.use('/api/v1/tours', tourRouter);
app.use('/api/v1/users', userRouter);
app.use('/api/v1/reviews', reviewRouter);
app.use('/api/v1/bookings', bookingRouter);

app.all('*', (req, res, next) => {
    const err = new AppError(
        `Can't find ${req.originalUrl} on this server!`,
        404,
    );
    next(err);
});

app.use(globalErrorHandler);

module.exports = app;