server.js

const fs = require('fs')
const path = require('path')
const express = require('express')
const microcache = require('route-cache');
const { createBundleRenderer } = require('vue-server-renderer')
const bundle = require('./dist/server-bundle.json');

const server = express();
const resolve = file => path.resolve(__dirname, file);
const templatePath = resolve('./index-server.html');
const template = fs.readFileSync(templatePath, 'utf-8');
const clientManifest = require('./dist/vue-ssr-client-manifest.json')

function createRenderer (bundle, options) {
  // https://github.com/vuejs/vue/blob/dev/packages/vue-server-renderer/README.md#why-use-bundlerenderer
  return createBundleRenderer(bundle, Object.assign(options, {
    // this property means that the bundle code will run in the same global context with the server 
    // process and recommended for performance.
    runInNewContext: false,
  }));
}

const renderer = createRenderer(bundle, {
  template,
  clientManifest,
});

const serve = path => express.static(resolve(path), {
  maxAge: 1000 * 60 * 60 // 1h static assets cache
})

server.use('/static', serve('./dist/static'));

function render (req, res) {
  const handleError = err => {
    if (err.url) {
      res.redirect(err.url);
    }
    else if(err.code === 404) {
      res.status(404).send('404 | Page Not Found');
    }
    else {
      // Render Error Page or Redirect
      res.status(500).send('500 | Internal Server Error');
      console.error(`error during render : ${req.url}`);
      console.error(err.stack);
    }
  }

  const context = {
    url: req.url,
  };
  renderer.renderToString(context, (err, html) => {
    if (err) {
      return handleError(err);
    }
    res.send(html);
  });
}

function healthcheck (req, res) {
    res.send('healthy')
}

// since this app has no user-specific content, every page is micro-cacheable.
// if your app involves user-specific content, you need to implement custom
// logic to determine whether a request is cacheable based on its url and
// headers.
// 30-second url response microcache.
// https://www.nginx.com/blog/benefits-of-microcaching-nginx/
server.use(microcache.cacheSeconds(30, req => req.originalUrl))

server.get('/healthcheck', healthcheck)
server.get('*', render);

const port = process.env.PORT || 8080
server.listen(port, () => {
  console.log(`server started at localhost:${port}`);
});