Node.js Link Preview Generator

gistfile1.txt

/**
 * @fileoverview Custom Link Preview Service using Puppeteer
 * @description Generates link previews by rendering webpages with Puppeteer
 * @reviewed Alan Spurlock - 2024-03-20
 */

const puppeteer = require('puppeteer')
const logger = require('../../utils/logger') //Where ever you might have your logger!

/**
 * Fetches a link preview and returns relevant metadata
 * @param {string} url - The URL to generate a preview for
 * @returns {Promise<Object>} An object containing title, description, image URL, and screenshot
 */
async function getLinkPreview(url) {
  logger.info(`[LINK-PREVIEW] Fetching link preview for ${url}`)

  let browser
  try {
    browser = await puppeteer.launch({ headless: 'new' })
    const page = await browser.newPage()

    // Set a reasonable viewport size
    await page.setViewport({ width: 1280, height: 800 })

    // Navigate to the URL
    await page.goto(url, { waitUntil: 'networkidle0' })

    // Extract metadata
    const metadata = await page.evaluate(() => {
      const getMetaContent = name => {
        const element = document.querySelector(`meta[name="${name}"], meta[property="og:${name}"]`)
        return element ? element.getAttribute('content') : null
      }

      return {
        title: document.title || getMetaContent('title'),
        description: getMetaContent('description'),
        image: getMetaContent('image')
      }
    })

    // If no image found in metadata, try to get the largest image on the page
    if (!metadata.image) {
      metadata.image = await page.evaluate(() => {
        const images = Array.from(document.images)
        if (images.length > 0) {
          const largestImage = images.reduce((largest, image) =>
            image.width * image.height > largest.width * largest.height ? image : largest
          )
          return largestImage.src
        }
        return null
      })
    }

    // Take a screenshot
    const screenshot = await page.screenshot({ encoding: 'base64' })

    return {
      ...metadata,
      screenshot: `data:image/png;base64,${screenshot}`
    }
  } catch (error) {
    console.error('Error fetching link preview:', error.message)
    return { title: '', description: '', image: '', screenshot: '' }
  } finally {
    if (browser) {
      await browser.close()
    }
  }
}

module.exports = {
  getLinkPreview
}