AWS Lambda: html2pdf (IDEA)

html2pdf.js

'use strict';

//
// AWS Lambda: idea_html2pdf (Node.js >= 18)
// File: index.js
// -- ITER IDEA, 2023.
// This function's source code is defined in the following GitHub Gist:
//      https://gist.github.com/uatisdeproblem/c4204778ed983f99bbbc18758ac1aed0
//

// required through AWS Lambda layer
const puppeteer = require('puppeteer-core');
const chromium = require('@sparticuz/chromium');
chromium.setHeadlessMode = true;
chromium.setGraphicsMode = false;

exports.handler = async (event, _, callback) => {
  const params = {
    body: event.body ?? '',
    header: event.header ?? '',
    footer: event.footer ?? '',
    pdfOptions: event.pdfOptions ?? {}
  };

  try {
    const data = await html2pdf(params);
    callback(null, data);
  } catch (err) {
    callback(err);
  }
};

async function html2pdf(params) {
  let browser;
  try {
    params.pdfOptions.displayHeaderFooter = Boolean(params.header || params.footer);
    params.pdfOptions.headerTemplate = params.header;
    params.pdfOptions.footerTemplate = params.footer;
    params.pdfOptions.format = params.pdfOptions.format ?? 'A4';
    params.pdfOptions.printBackground =
      params.pdfOptions.printBackground === undefined ? true : params.pdfOptions.printBackground;
    params.pdfOptions.margins = params.pdfOptions.margins ?? { top: '2cm', right: '1cm', bottom: '2cm', left: '1cm' };

    const browser = await puppeteer.launch({
      args: chromium.args.concat('--font-render-hinting=none'),
      defaultViewport: chromium.defaultViewport,
      executablePath: await chromium.executablePath(),
      headless: chromium.headless,
    });

    const page = await browser.newPage();
    await page.setContent(params.body, { waitUntil: 'networkidle2' });
    await page.emulateMediaType('screen');

    const pdfData = await page.pdf(params.pdfOptions);

    if (browser) await browser.close();

    return pdfData.toString('base64');
  } catch(error) {
    if (browser) await browser.close();
    throw error;
  }
}

html2pdf_viaS3Bucket.js

'use strict';

//
// AWS Lambda: idea_html2pdf_viaS3Bucket (Node.js >= 18)
// Alternate version of idea_html2pdf that uses an intermediate S3 bucket to avoid Lambda's payload limits.
// File: index.js
// -- ITER IDEA, 2023.
// This function's source code is defined in the following GitHub Gist:
//      https://gist.github.com/uatisdeproblem/c4204778ed983f99bbbc18758ac1aed0
//

// required through AWS Lambda layer
const puppeteer = require('puppeteer-core');
const chromium = require('@sparticuz/chromium');
chromium.setHeadlessMode = true;
chromium.setGraphicsMode = false;

const { S3Client } = require('@aws-sdk/client-s3');
const { Upload } = require('@aws-sdk/lib-storage');

const s3 = new S3Client();

exports.handler = async (event, _, callback) => {
  const params = {
    body: event.body ?? '',
    header: event.header ?? '',
    footer: event.footer ?? '',
    pdfOptions: event.pdfOptions ?? {},
    s3Bucket: event.s3Bucket,
    s3Prefix: event.s3Prefix
  };

  try {
    const data = await html2pdfViaS3Bucket(params);
    callback(null, data);
  } catch (err) {
    callback(err);
  }
};

async function html2pdfViaS3Bucket(params) {
  let browser;
  try {
    params.pdfOptions.displayHeaderFooter = Boolean(params.header || params.footer);
    params.pdfOptions.headerTemplate = params.header;
    params.pdfOptions.footerTemplate = params.footer;
    params.pdfOptions.format = params.pdfOptions.format ?? 'A4';
    params.pdfOptions.printBackground =
      params.pdfOptions.printBackground === undefined ? true : params.pdfOptions.printBackground;
    params.pdfOptions.margins = params.pdfOptions.margins ?? { top: '2cm', right: '1cm', bottom: '2cm', left: '1cm' };

    const browser = await puppeteer.launch({
      args: chromium.args.concat('--font-render-hinting=none'),
      defaultViewport: chromium.defaultViewport,
      executablePath: await chromium.executablePath(),
      headless: chromium.headless,
    });

    const page = await browser.newPage();
    await page.setContent(params.body, { waitUntil: 'networkidle2' });
    await page.emulateMediaType('screen');

    const pdfData = await page.pdf(params.pdfOptions);

    const s3Bucket = params.s3Bucket ?? 'idea-downloads';
    const s3Prefix = params.s3Prefix ?? 'html2pdf';
    const s3ParamsToRetrievePDF = await uploadPDFDataInS3Bucket(pdfData, s3Bucket, s3Prefix);

    if (browser) await browser.close();

    return s3ParamsToRetrievePDF;
  } catch(error) {
    if (browser) await browser.close();
    throw error;
  }
}

async function uploadPDFDataInS3Bucket(buffer, s3Bucket, s3Prefix) {
  const Bucket = s3Bucket;
  const Key = s3Prefix.concat('/', new Date().getTime().toString().concat(Math.random().toString(36).slice(2)), '.pdf');

  const upload = new Upload({ client: s3, params: { Bucket, Key, Body: buffer } });
  await upload.done();

  return { Bucket, Key };
}