pdf-pager

pdf-pager

A library for rendering HTML to PDF, with support for headers and footers.

Why?

I wanted a modern way to develop PDFs with static headers and footers, and I wanted to use a modern browser engine to do it.

I tried a few solutions but was unable to find anything which worked exactly like how I wanted.

How it works

• The process begins by rendering the HTML template using Puppeteer.
• Extracts and measures the dimensions of the header and footer, capturing each as a separate PDF.
• Rerenders the template excluding the header and footer.
• Captures the main content as a PDF, with careful attention to correct pagination.
• Calculates the height of the main content area by subtracting the combined heights of the header and footer from the total paper height.
• Ensures the calculated height is valid; throws an error if it's not.
• Captures the main content as a PDF using the adjusted height.
• Creates a new PDF document and loads the content from the main content PDF.
• Iterates through each page:
  • Adjusts each page's size to accommodate the header and footer.
  • If available, embeds the header at the top of the page.
  • If available, embeds the footer at the bottom of the page.
  • Embeds the main content between the header and footer.
• Saves and returns the modified document.

Usage

import {PDFPager} from "pdf-pager";

// see tests/examples/invoice.html
const file = await PDFPager.create().fromFile(path.join(__dirname, 'invoice.html'));
await fs.promises.writeFile('invoice.pdf', file);

Template

The template should contain a #header and #footer element. These will be used to capture the header and footer.

Future Plans

• Support page numbers

Other Solutions

• https://wkhtmltopdf.org/ -- Uses WebKit to render HTML to PDF
• https://www.princexml.com/ -- Commercial solution, uses an older browser engine
• https://pdfkit.org/ -- Draw PDFs using a canvas like API
• https://weasyprint.org/ -- Not browser based, no JS support

References

• https://github.com/Hopding/pdf-lib/issues/128
• https://github.com/Hopding/pdf-lib/issues/143 -- PaperSizes