Ghost/core/server/web/parent/app.js

const debug = require('@tryghost/debug')('web:parent');
const config = require('../../../shared/config');
const express = require('../../../shared/express');
const compress = require('compression');
const mw = require('./middleware');
const vhost = require('@tryghost/vhost-middleware');

/**
 * @param {Object} options
 * @param {Boolean} [options.start]
 * @param {Boolean} [options.backend]
 * @param {Boolean} [options.frontend]
 */
module.exports = function setupParentApp({start, frontend = true, backend = true}) {
    debug('ParentApp setup start');
    const parentApp = express('parent');

    parentApp.use(mw.requestId);
    parentApp.use(mw.logRequest);

    // Register event emmiter on req/res to trigger cache invalidation webhook event
    parentApp.use(mw.emitEvents);

    // enabled gzip compression by default
    if (config.get('compress') !== false) {
        parentApp.use(compress());
    }

    // This sets global res.locals which are needed everywhere
    // @TODO: figure out if this is really needed everywhere? Is it not frontend only...
    parentApp.use(mw.ghostLocals);

    // Mount the express apps on the parentApp

    if (backend) {
        debug('Mounting bakcend: ADMIN + API');
        const backendApp = require('./backend')();
        parentApp.use(vhost(config.getBackendMountPath(), backendApp));
    }

    if (frontend) {
        debug('Mounting frontend: SITE + MEMBERS');
        const frontendApp = require('./frontend')({start});
        parentApp.use(vhost(config.getFrontendMountPath(), frontendApp));
    }
    debug('ParentApp setup end');

    return parentApp;
};