app.js

const express = require('express');
const app = express();
const morgan = require('morgan');
const bodyParser = require('body-parser');
const mongoose = require('mongoose');

const productRoutes = require('./api/routes/products');
const orderRoutes = require('./api/routes/orders');
const userRoutes = require('./api/routes/user');

mongoose.connect('mongodb://node-shop:' + process.env.MONGO_ATLAS_PW + '@node-rest-shop-shard-00-00-qr3c3.mongodb.net:27017,node-rest-shop-shard-00-01-qr3c3.mongodb.net:27017,node-rest-shop-shard-00-02-qr3c3.mongodb.net:27017/test?ssl=true&replicaSet=node-rest-shop-shard-0&authSource=admin', {
    useMongoClient: true
});
mongoose.Promise = global.Promise;

app.use(morgan('dev'));
app.use('/uploads', express.static('uploads'));
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());

app.use((req, res, next) => {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization');
    if (req.method === 'OPTIONS') {
        res.header('Access-Control-Allow-Methods', 'PUT, POST, PATCH, DELETE, GET');
        return res.statusCode(200).json({});
    }
    next();
});

app.use('/products', productRoutes);
app.use('/orders', orderRoutes);
app.use('/user/', userRoutes);

app.use((req, res, next) => {
    const error = new Error('Not found');
    error.status = 404;
    next(error);
});

app.use((error, req, res, next) => {
    res.status(error.status || 500);
    res.json({
        error: {
            message: error.message
        }
    });
})

module.exports = app;