SPA meta-tag renderer (for fb bots etc)

express-puppeteer-server.ts

import express from 'express';
import puppeteer from 'puppeteer';
import ua from 'useragent';

const isBot = (agent: ua.Details) => {
  return !agent.webkit && !agent.opera && !agent.ie &&
      !agent.chrome && !agent.safari && !agent.mobile_safari &&
      !agent.firefox && !agent.mozilla && !agent.android;
}

const app = express();

app.use(async (req, res) => {

  const renderUrl = `https://www.strim.no${req.path}`;
  const agent = ua.is(req.headers['user-agent'] || '');

  console.log(`fetching: ${renderUrl}`, agent);

  try {
      const browser = await puppeteer.launch({
        'args' : [
          '--no-sandbox',
          '--disable-setuid-sandbox'
        ]
      })
      const page = await browser.newPage();
      await page.setUserAgent('Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36');
      await page.goto(renderUrl, {
          waitUntil: 'networkidle0',
      });
      const html = await page.evaluate(() => {
          return document.documentElement.innerHTML;
      });
      await browser.close();

      if (!isBot(agent)) {
        res.contentType('text/plain');
        res.send(html);
      } else {
        res.send(html);
      }
  } catch (err) {
      res.send(err)
  }
});

const port = process.env.PORT || 3000;
app.listen(port, () => {
    console.log(`Web server is running at port ${port}`);
});