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Generate high-quality PDF from HTML using Pyppeteer

Marcelo | Founder

Oct 9, 2024

Introduction to Pyppeteer for PDF Generation

Pyppeteer stands out as an excellent tool for generating PDFs from HTML due to its flexibility and ability to render content exactly as a browser would. Unlike traditional Python PDF libraries such as ReportLab or PyPDF2, which focus on constructing PDFs programmatically, Pyppeteer offers the advantage of working with HTML and CSS directly. This allows you to design your document using web standards, ensuring that complex layouts, fonts, and even JavaScript-powered dynamic elements are rendered perfectly.

For SaaS developers looking to create PDF reports directly from web applications, Pyppeteer provides a streamlined solution to generate high-quality, dynamic PDFs with minimal friction.

You can check the full documentation here.

Comparing Pyppeteer with Other PDF Libraries and Tools

When evaluating PDF generation libraries for your SaaS, it’s essential to consider the unique strengths of each tool. Here’s how Pyppeteer compares to Playwright, ReportLab, and PyPDF2:

• Pyppeteer vs. Playwright: Both Pyppeteer and Playwright can generate PDFs from HTML, but Playwright is generally more robust for broader web automation use cases, supporting multiple browsers like Firefox and WebKit, whereas Pyppeteer focuses solely on Chromium. If your primary goal is HTML-to-PDF conversion and you don’t need multi-browser support, Pyppeteer may offer simpler usage. Playwright, on the other hand, excels when broader testing or automation beyond Chromium is needed.

• Pyppeteer vs. ReportLab: ReportLab is a powerful Python library for creating PDFs programmatically. However, it doesn’t support HTML/CSS rendering directly. ReportLab is more suited for constructing PDFs from scratch using Python, making it ideal for static reports or invoices that don’t rely on existing HTML content. In contrast, Pyppeteer allows you to leverage your existing HTML/CSS designs, which is more efficient for modern web applications.

• Pyppeteer vs. PyPDF2: PyPDF2 focuses on manipulating existing PDFs—merging, splitting, rotating, etc. While useful for handling PDFs once they’re created, PyPDF2 doesn’t offer HTML-to-PDF conversion. This makes Pyppeteer the superior option for generating PDFs dynamically from HTML content, especially when working with web-based layouts.

Guide to generate pdf from html using python pyppeteer

Setting Up Your Environment for Pyppeteer PDF Generation

Prerequisites: What You Need to Get Started with Pyppeteer

To begin, you’ll need:

• Python 3.6 or later

• Node.js (required for Puppeteer/Chromium)

• Basic knowledge of HTML, CSS, and Python

Check your Python and Node.js installations:

python --version
node --version

If Node.js is not installed, download it from nodejs.org.

Installing Pyppeteer in Your Python Project

Install Pyppeteer using pip:

This command installs Pyppeteer along with a bundled Chromium version for rendering.

Integrating Pyppeteer with Your Existing HTML Rendering Setup

With Pyppeteer installed, you can now integrate it with your existing HTML rendering pipeline. If you’re using a template engine like Jinja2, you can dynamically populate the HTML content and pass it to Pyppeteer.

Here’s a basic Jinja2 template:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Invoice</title>
  <style>
    body { font-family: Arial, sans-serif; }
    .header { text-align: center; font-size: 24px; }
    .content { padding: 20px; }
  </style>
</head>
<body>
  <div class="header">
    <h1>Invoice #{{ invoice_id }}</h1>
  </div>
  <div class="content">
    <p>Customer: {{ customer_name }}</p>
    <p>Total: ${{ total_amount }}</p>
  </div>
</body>
</html>

How to Generate a PDF from HTML Using Pyppeteer

Step-by-Step Guide to Converting HTML to PDF Using Pyppeteer

To generate a PDF from HTML, use the following Python script:

import asyncio
from pyppeteer import launch
async def html_to_pdf(html_content, output_path):
    browser = await launch()
    page = await browser.newPage()
    await page.setContent(html_content)
    await page.pdf({'path': output_path, 'format': 'A4'})
    await browser.close()
html_content = '''
<!DOCTYPE html>
<html>
  <body>
    <h1>Hello, PDF World!</h1>
  </body>
</html>
'''
asyncio.get_event_loop().run_until_complete(html_to_pdf(html_content, 'output.pdf'))

This script renders your HTML and generates a PDF file.

Customizing PDF Output: Headers, Footers, and Page Formats

You can easily customize the PDF format with Pyppeteer. Add headers, footers, or set the page size using the pdf() function:

await page.pdf({
    'path': 'output.pdf',
    'format': 'A4',
    'displayHeaderFooter': True,
    'footerTemplate': '<span class="pageNumber"></span> of <span class="totalPages"></span>',
    'margin': {'top': '20px', 'bottom': '40px'}
})

This code adds page numbers to the footer, customizing your PDF output.

Handling Complex HTML Elements: Images, CSS, and JavaScript in PDFs

Pyppeteer excels at handling complex HTML elements like images, advanced CSS, and even JavaScript-powered charts. You can generate PDFs with complex layouts that would be difficult to achieve with most other PDF libraries.

For example, to render a JavaScript chart into your PDF:

<canvas id="myChart"></canvas>
<script>
var ctx = document.getElementById('myChart').getContext('2d');
new Chart(ctx, {
  type: 'bar',
  data: { /* chart data */ },
});
</script>

Troubleshooting Common Issues When Using Pyppeteer for HTML to PDF

There are several common issues that developers face when generating PDFs from HTML using Pyppeteer:

• Fonts not displaying correctly: Ensure that any web fonts or custom fonts are fully loaded by waiting for the network to idle using await page.waitForFunction().

• Media type problems: Pyppeteer renders HTML using the screen media type by default. To ensure your document appears as it would on paper, you need to force the media type to ‘print’:

await page.emulateMediaType('print')

• Print background property: By default, background images or colors may not appear in your PDF. You can enable background printing by setting the printBackground property to True:

await page.pdf({'path': 'output.pdf', 'printBackground': True})

• JavaScript not executing: If your HTML content relies on JavaScript, ensure that it fully executes before creating the PDF by waiting for network events or DOM changes.

Enhancing PDF Generation with Pyppeteer and a PDF API

For SaaS applications that need to generate PDFs at scale, integrating with a third-party PDF API can be a more efficient approach. APIs such as pdforge offer extensive features like watermarking, encryption, and built-in scaling capabilities. They simplify the process of handling high volumes of PDF generation requests without the overhead of managing your own infrastructure.

Here’s an example of how you might integrate with a PDF API:

import requests
import json

url = 'https://api.pdforge.com/v1/pdf/sync'
headers = {
    'Authorization': 'Bearer your-api-key',
    'Content-Type': 'application/json'
}
data = {
    'templateId': 'your-template',
    'data': {
        'html': 'your-html'
    }
}

response = requests.post(url, headers=headers, data=json.dumps(data))
with open('output.pdf', 'wb') as f:
        f.write(response.content)

Using a PDF API like this can help offload the heavy lifting involved in creating and managing large-scale PDF generation.

Conclusion

Pyppeteer is a highly versatile tool for converting HTML to PDF, especially when working with complex, web-based designs. For developers building SaaS applications that require dynamic, high-quality PDFs, Pyppeteer offers an efficient and flexible solution.

If your needs involve handling large volumes of PDFs, integrating a third-party PDF API, such as pdforge, can help you scale and automate your PDF generation processes. For simpler PDF manipulation tasks, PyPDF2 or ReportLab may suffice, but for HTML-driven content, Pyppeteer is the clear choice.