app.js

const express = require('express');
const path = require('path');
const bodyParser = require('body-parser');
const graphqlHttp = require('express-graphql');
const knexLogger = require('knex-logger');
const morgan = require('morgan');
const db = require('./knex');
const cors = require('cors');
const compression = require('compression');

// importing the graphql schema and resolver functions.
const graphQlSchema = require('./graphql/schema/index');
const graphQlResolvers = require('./graphql/resolvers/index');

// express server.
const app = express();
app.use(cors());

// Compress all HTTP responses
app.use(compression());

// logging.
app.use(knexLogger(db));
app.use(morgan('dev'));

// body parser.
app.use(bodyParser.json());

// serves static build files
// uses pug to serve maintenace page if the maintenance mode is turned on.
if (process.env.MAINTENANCE === 'true') {
    app.use('/style', express.static('maintenance/style'));
    app.use('/image', express.static('maintenance/img'));
    app.set('views', './maintenance/views');
    app.set('view engine', 'pug');
} else {
    app.use(express.static(path.join(__dirname, 'client/build')));
}

// setting up the graphql end points.
// passing in the graphql schema and resolver functions.
app.use('/graphql',
    graphqlHttp({
        schema: graphQlSchema,
        rootValue: graphQlResolvers,
        graphiql: true
    }));

// renders react files if request doesn't go to api
app.get('/*', (req, res) => {
    // serves maintenance static page if the maintenance mode is turned on.
    if (process.env.MAINTENANCE === 'true') {
        res.render('maintenance', {start: process.env.MAINTENANCE_START, end: process.env.MAINTENANCE_END});
    } else {
        res.sendFile('index.html', { root: './client/build' });
    }
});

// use port no. 5000 for server if environment variable is not present.
const port = process.env.PORT || 5000;
const server = app.listen(port, () => {
    console.log('Server Started');
});

module.exports = server;