server.js

//const createError = require('http-errors');
const express = require('express');
const path = require('path');
const cookieParser = require('cookie-parser');
const logger = require('morgan');
const cors = require('cors');

const usersRouter = require('./routes/users');
const booksRouter = require('./routes/book'); 
const booksinstanceRouter = require('./routes/bookInstance'); 
const authorsRouter = require('./routes/author'); 
const genresRouter = require('./routes/genre'); 

const compression = require('compression');
const helmet = require('helmet');

const app = express();

// Set up mongoose connection
const mongoose = require('mongoose');
const dev_db_url = 'mongodb://localhost:27017/library';
const mongoDB = process.env.MONGODB_URI || dev_db_url;
mongoose.connect(mongoDB, {
  useCreateIndex: true,
  useFindAndModify: false,
  useNewUrlParser: true,
  useUnifiedTopology: true
});
mongoose.Promise = global.Promise;
const db = mongoose.connection;
db.on('open', () => console.info('Database connected!✨'));
db.on('error', console.error.bind(console, 'MongoDB connection error:'));


app.use(cors('*'));

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(helmet());
app.use(compression()); // Compress all routes

//app.use(express.static(path.join(__dirname, 'public')));

app.use('/users', usersRouter);
app.use('/books', booksRouter);
app.use('/booksinstances', booksinstanceRouter);
app.use('/authors', authorsRouter);
app.use('/genres', genresRouter);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.send(err);
});

// Server static assets if in production
if (process.env.NODE_ENV === 'production') {
  // Set static folder
  app.use(express.static('client/build'));

  app.get('*', (req, res) => {
    res.sendFile(path.resolve(__dirname, 'client', 'build', 'index.html'));
  });
}

const port = process.env.PORT || 5000;

app.listen(port, () => console.log(`Server running on port ${port}`));