server.js

const express = require('express')
const app = express()
const bodyParser = require('body-parser');
const puppeteer = require('puppeteer')

app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

let browser

(async () => {
    browser = await puppeteer.launch({
        headless: true,
        slowMo: 250,
        args: ['--no-sandbox', '--disable-setuid-sandbox']
    });
})();

app.use(express.json());

app.get('/', (req, res) => {
    res.send('headless chrome api is ready to serve')
})

app.post('/content', async (req, res) => {
    const url = req.body.url
    const js = req.body.js
    try {
        if (url) {
            console.log('open ' + url)
            const content = await ssr(url, js)
            res.json(content)
        } else {
            res.status(400).send("missing input value")
        }
    } catch (error) {
        console.error(error)
        res.status(500).send(error)
    }
})

app.post('/pdf', async (req, res) => {
    const {html, paperSize} = req.body
    try {
        const page = await browser.newPage();
        await page.setContent(html);
        const result = await page.pdf({
            format: paperSize || 'A4',
            printBackground: true,
        });
        res.contentType('application/pdf');
        res.send(result);
        page.close()
    } catch (error) {
        res.status(500).send({
            error: true,
            msg: error.message,
        })
    }
})

async function ssr(url, js = false) {
    const page = await browser.newPage();
    if (js) {
        await page.goto(url, {waitUntil: 'networkidle0'});
    } else {
        await page.goto(url);
    }
    const html = await page.content(); // serialized HTML of page DOM.
    page.close()
    return html;
}

const port = 3000
app.listen(port, () => {
    console.log(`Example app listening on port ${port}!`)
})