Template Structure

Templates are simple PHP files that use a mix of HTML and PHP. Data from the n8n webhook request is passed to the PHP script, which then renders the HTML dynamically.

Here’s the basic structure of a template file (e.g., invoice.php):

php

<?php
// Get the JSON data from the request body
$data = json_decode(file_get_contents('php://input'), true);

// Extract variables for easier use in HTML
$invoiceNumber = $data['invoiceNumber'];
$clientName = $data['clientName'];
$items = $data['items'];
?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Invoice #<?php echo htmlspecialchars($invoiceNumber); ?></title>
    <style>
        body { font-family: sans-serif; }
        .container { width: 800px; margin: 0 auto; }
        h1 { color: #333; }
        /* Add your custom CSS here */
    </style>
</head>
<body>
    <div class="container">
        <h1>Invoice</h1>
        <p><strong>Invoice Number:</strong> <?php echo htmlspecialchars($invoiceNumber); ?></p>
        <p><strong>Client:</strong> <?php echo htmlspecialchars($clientName); ?></p>

        <h2>Items</h2>
        <table>
            <thead>
                <tr>
                    <th>Description</th>
                    <th>Quantity</th>
                    <th>Price</th>
                </tr>
            </thead>
            <tbody>
                <?php foreach ($items as $item): ?>
                <tr>
                    <td><?php echo htmlspecialchars($item['description']); ?></td>
                    <td><?php echo htmlspecialchars($item['quantity']); ?></td>
                    <td>$<?php echo htmlspecialchars($item['price']); ?></td>
                </tr>
                <?php endforeach; ?>
            </tbody>
        </table>
    </div>
</body>
</html>

Creating a New Template

To create a new PDF template, follow these steps:

Create a new PHP file in the ./templates/ directory (e.g., certificate.php).
Add your HTML and CSS. This content will form the visual layout of your PDF. Since Gotenberg renders this HTML, you can use modern CSS to style the document.
Use PHP to embed dynamic data.

The webhook data is available as a JSON string in the request body. You must first decode it using json_decode(file_get_contents('php://input'), true).
Access the data using array keys, like $data['key'].
Always use htmlspecialchars() when echoing data to prevent XSS (Cross-Site Scripting) vulnerabilities.
Use PHP control structures like foreach to loop through arrays (e.g., a list of invoice items).

Using a New Template in n8n

After creating your new template file, you need to update the n8n workflow to use it.

Open the n8n workflow in your browser.
Find the HTTP Request node that sends the data to the Gotenberg service.
Update the URL. Change the URL to point to your new template file. For example, if your new file is certificate.php, the URL will be http://nginx/certificate.php. The name php is the service name defined in docker-compose.yml, allowing the n8n container to communicate with the PHP-FPM container.

By following these steps, you can create a wide variety of professional and branded PDF documents.

Template Structure ​

Creating a New Template ​

Using a New Template in n8n ​

Template Structure

Creating a New Template

Using a New Template in n8n