Puppeteer Screenshot Issue: Text Not Displaying

Other Questions Puppeteer
1

Issue: When using Puppeteer within an Express Docker setup, screenshots sometimes omit local styled text, possibly due to execution race conditions. See sample code below.

const webApp = require('express')();
const path = require('path');

webApp.post('/captureImage', async (req, res) => {
  const browserLib = require('puppeteer');
  try {
    const htmlData = `<html><head><style>${req.body.customCSS}</style></head><body>${req.body.htmlContent}</body></html>`;
    const browser = await browserLib.launch({ args: ['--no-sandbox'] });
    const tab = await browser.newPage();
    await tab.setViewport({ width: 1200, height: 1000 });
    await tab.setContent(htmlData, { waitUntil: 'load' });
    const output = path.join(__dirname, 'captures', `${req.body.fileName}.png`);
    await tab.screenshot({ path: output });
    await browser.close();
    res.status(201).send('Image captured successfully');
  } catch (error) {
    res.status(500).send('Screenshot failed');
  }
});
2

hey, try using waitForFunction to ensure the text is rendered before taking the screenshot. i had a similiar issue and a little delay fixed it in docker. hope this helps!

3

hey, i solved it by switching wait condition to networkidle0 and adding a brief delay after setContent. it seems text sometimes loads late. give that a shot.

4

I encountered a similar problem in one of my projects. My approach was to explicitly check for the presence of key DOM elements before capturing the screenshot. Instead of relying solely on ‘load’ or ‘networkidle0’, I implemented a custom wait by using a selector check with page.waitForSelector to ensure the rendered text was present. Adjusting the timeout settings also made a significant difference. This change helped accommodate any delayed rendering in the Docker environment and resulted in more reliable screenshot captures.

5

The challenge you’re experiencing appears to be related to timing issues within the rendered page. In similar cases I’ve encountered, incorporating a wait based solely on ‘load’ or ‘networkidle0’ isn’t always enough. Instead, I’ve used a mechanism to continuously poll the page to check when all dynamic content, especially locally styled text, is fully rendered before taking the screenshot. Adjusting browser launch options and ensuring the Docker environment has sufficient resources for rendering tasks also helped in my experience.