如何在DOMPDF中使用PHP变量（含Session变量）生成动态PDF？

The core issue here is that when you pass an HTML string containing PHP tags directly to loadHtml(), DOMPDF doesn't execute that PHP code—it treats the <?php ... ?> blocks as plain text. That's why your dynamic session variables aren't showing up correctly. Here are a few reliable ways to inject dynamic data before generating the PDF:

1. Use Output Buffering with a Separate PHP Template #

This is the most straightforward approach for PHP-based dynamic content. Create a separate PHP file that generates your HTML (with embedded PHP variables), then capture its output and pass it to DOMPDF.

Step 1: Create a Template File (certificate_template.php) #

<?php session_start(); ?>
<style>
div.background { background: #ffffff; border: 4px solid black; margin: 10px; }
div.transbox { margin: 3px; background-color: #ffffff; border: 1px solid black; }
div.transbox p { margin: 1%; color: #000000; }
#middle { margin: 5px; background-color: #ffffff; border: 1px solid #fff; }
body{ background-color: #f6f6f6; }
.logowhite{ float: right; }
.logo { clear: right; text-align: center; }
</style>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css"/>
<link href="https://vip-organon-us-hcp-com-develop.go-vip.net/nexplanontraining/wp-content/themes/twentytwentyone-child/assets/css/main.min2.css" media="all" type="text/css" rel="stylesheet"/>
<body id="thank-you" class="base"><div id="middle">
<div class="background">
<div class="transbox">
<div class="logowhite">
<img alt="" src="org_logo.jpg" /></div>
<div class="logo">
<img src="nexplanon.jpg" alt="" />
<p style="font-size:1.35rem;color:#00F;text-transform: uppercase;"><?php echo $_SESSION["first_name"]; ?> &nbsp; <?php echo $_SESSION["last_name"]; ?></p>
<p style="font-size: 1.25rem;line-height:25px;">This certificate serves as confirmation of the completion of the Mandatory Training Module<BR> on the updated insertion and removal procedures for NEXPLANON.</p>
<div style="width: 70%;margin: auto;">
<p style="float: left;font-size: 1.25rem;"><B>Training Date:</B> <span style="color: #00F;"><?php echo $_SESSION["mandatory_date"]; ?></span>
</p>
<img style="float:right;" alt="" src="sign.jpg" />
</div>
</div>
<div style="width: 90%;margin: auto;">
<p style="clear: both;margin-bottom: 0%;line-height:18px;"><BR>I attested that I completed the Organon-sponsored Mandatory Training Module on the updated insertion and removal procedures for NEXPLANON in its entirety. I understand that only healthcare providers who have completed the Organon-sponsored Clinical Training Program for NEXPLANON may order, insert, and remove NEXPLANON.<BR><BR>
I certified that I am authorized to perform the procedures entailed in the insertion and removal of NEXPLANON in the jurisdiction where I practice. I attest that if there are specific state requirements in the state where I practice, I have met all appropriate state conditions including but not limited to collaborative or signing agreement with an MD/DO.<BR><BR>
If I am a resident or student in advanced practice training, I understand that I should only administer NEXPLANON under the supervision of an attending healthcare provider who has also been trained on the procedures to insert and remove NEXPLANON.</p>
</div><br/>
<div style="padding-bottom: -2%;">
<p style="font-size: 0.7rem;float: left;">© 2021 Organon group of companies. All rights reserved. ORGANON and the ORGANON Logo are trademarks of the Organon group of companies.</p>
<p style="float: right;font-size: 0.7rem;">US-XPL-115639 12/21</p>
<p style="clear: both;margin-bottom: 0%;">
</p>
</div>
</div>
</div>
</div></body>

Step 2: Modify Your Main PDF Generation Code #

<?php
session_start();
// Ensure $mandatory_date, $first_name, $last_name are defined before setting sessions
$_SESSION["mandatory_date"] = $mandatory_date; 
$_SESSION["first_name"] = $first_name; 
$_SESSION["last_name"] = $last_name; 

require_once "./dompdf/autoload.inc.php";
use Dompdf\Dompdf;
use Dompdf\Options;

// Start output buffering to capture the template's rendered HTML
ob_start();
include 'certificate_template.php'; // Executes PHP and generates final HTML
$html = ob_get_clean(); // Get the generated HTML and clear the buffer

$dompdf = new Dompdf();
$dompdf->set_option('isRemoteEnabled', TRUE);
$dompdf->loadHtml($html);
$dompdf->setPaper('A4', 'landscape');
$dompdf->render();
$dompdf->stream("training-certificate", array("Attachments"=>0));
?>

2. Use String Replacement (Inline Template) #

If you prefer to keep the HTML in the same file, replace placeholders in your HTML string with actual session values before passing it to DOMPDF:

<?php
session_start();
$_SESSION["mandatory_date"] = $mandatory_date; 
$_SESSION["first_name"] = $first_name; 
$_SESSION["last_name"] = $last_name; 

require_once "./dompdf/autoload.inc.php";
use Dompdf\Dompdf;
use Dompdf\Options;

// Define HTML with placeholders instead of PHP tags
$htmlTemplate = '
<style>
div.background { background: #ffffff; border: 4px solid black; margin: 10px; }
div.transbox { margin: 3px; background-color: #ffffff; border: 1px solid black; }
div.transbox p { margin: 1%; color: #000000; }
#middle { margin: 5px; background-color: #ffffff; border: 1px solid #fff; }
body{ background-color: #f6f6f6; }
.logowhite{ float: right; }
.logo { clear: right; text-align: center; }
</style>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css"/>
<link href="https://vip-organon-us-hcp-com-develop.go-vip.net/nexplanontraining/wp-content/themes/twentytwentyone-child/assets/css/main.min2.css" media="all" type="text/css" rel="stylesheet"/>
<body id="thank-you" class="base"><div id="middle">
<div class="background">
<div class="transbox">
<div class="logowhite">
<img alt="" src="org_logo.jpg" /></div>
<div class="logo">
<img src="nexplanon.jpg" alt="" />
<p style="font-size:1.35rem;color:#00F;text-transform: uppercase;">{FIRST_NAME} &nbsp; {LAST_NAME}</p>
<p style="font-size: 1.25rem;line-height:25px;">This certificate serves as confirmation of the completion of the Mandatory Training Module<BR> on the updated insertion and removal procedures for NEXPLANON.</p>
<div style="width: 70%;margin: auto;">
<p style="float: left;font-size: 1.25rem;"><B>Training Date:</B> <span style="color: #00F;">{MANDATORY_DATE}</span>
</p>
<img style="float:right;" alt="" src="sign.jpg" />
</div>
</div>
<div style="width: 90%;margin: auto;">
<p style="clear: both;margin-bottom: 0%;line-height:18px;"><BR>I attested that I completed the Organon-sponsored Mandatory Training Module on the updated insertion and removal procedures for NEXPLANON in its entirety. I understand that only healthcare providers who have completed the Organon-sponsored Clinical Training Program for NEXPLANON may order, insert, and remove NEXPLANON.<BR><BR>
I certified that I am authorized to perform the procedures entailed in the insertion and removal of NEXPLANON in the jurisdiction where I practice. I attest that if there are specific state requirements in the state where I practice, I have met all appropriate state conditions including but not limited to collaborative or signing agreement with an MD/DO.<BR><BR>
If I am a resident or student in advanced practice training, I understand that I should only administer NEXPLANON under the supervision of an attending healthcare provider who has also been trained on the procedures to insert and remove NEXPLANON.</p>
</div><br/>
<div style="padding-bottom: -2%;">
<p style="font-size: 0.7rem;float: left;">© 2021 Organon group of companies. All rights reserved. ORGANON and the ORGANON Logo are trademarks of the Organon group of companies.</p>
<p style="float: right;font-size: 0.7rem;">US-XPL-115639 12/21</p>
<p style="clear: both;margin-bottom: 0%;">
</p>
</div>
</div>
</div>
</div></body>
';

// Replace placeholders with session values
$html = str_replace(
    ['{FIRST_NAME}', '{LAST_NAME}', '{MANDATORY_DATE}'],
    [$_SESSION["first_name"], $_SESSION["last_name"], $_SESSION["mandatory_date"]],
    $htmlTemplate
);

$dompdf = new Dompdf();
$dompdf->set_option('isRemoteEnabled', TRUE);
$dompdf->loadHtml($html);
$dompdf->setPaper('A4', 'landscape');
$dompdf->render();
$dompdf->stream("training-certificate", array("Attachments"=>0));
?>

3. Use a Template Engine (For Complex Projects) #

For larger applications, using a template engine like Twig or Blade can simplify managing dynamic HTML. These engines handle variable injection automatically, and you can render the template to a string before passing it to DOMPDF.

Quick Example with Twig: #

1. Install Twig via Composer
2. Create a Twig template file (certificate.twig) with variables like {{ first_name }}
3. Render the template to HTML and pass to DOMPDF:

<?php
session_start();
require_once "./dompdf/autoload.inc.php";
require_once './vendor/autoload.php'; // Twig autoloader

$loader = new \Twig\Loader\FilesystemLoader('./templates');
$twig = new \Twig\Environment($loader);

$html = $twig->render('certificate.twig', [
    'first_name' => $_SESSION["first_name"],
    'last_name' => $_SESSION["last_name"],
    'mandatory_date' => $_SESSION["mandatory_date"]
]);

$dompdf = new Dompdf();
$dompdf->set_option('isRemoteEnabled', TRUE);
$dompdf->loadHtml($html);
// ... rest of your PDF generation code
?>

Key Notes: #

• Ensure your session variables are properly initialized and accessible before generating the HTML.
• For local images, use absolute file paths or base64 encoding to ensure DOMPDF can load them correctly.

内容的提问来源于stack exchange，提问作者Gopal