Using PD4ML with Zend Framework 2 (ZF2)

This walkthrough adds a "Page as PDF" button to a Zend Framework 2 view, using the Zend Framework tutorial's own Albums sample application as the base. It builds directly on the PHP Wrapper pattern -- shelling out to the Pd4Cmd command-line tool from a small PHP script -- so it's worth reading that page first if the general approach is unfamiliar.

This page was checked against the current PD4ML source before republishing, not just carried over. The Zend Framework 2 side of the walkthrough (the controller action, the view template, the module config) is unchanged, since none of that depends on PD4ML internals. What did need correcting is the Pd4Cmd invocation itself:

The original sample invokes it as java ... -cp $jar Pd4Cmd ... -- a bare, unqualified Pd4Cmd class name. That hasn't resolved for some time: Pd4Cmd lives in the com.pd4ml.tools package, not the default package, so a plain classpath launch needs the fully-qualified name. The packaged jar's manifest already declares com.pd4ml.tools.Pd4Cmd as its Main-Class, so the simplest fix -- and the form PD4ML's own command-line reference documents -- is to drop -cp/the class name entirely and launch the jar directly with -jar. Both PHP scripts below use the corrected form.

Prerequisites

Follow the Zend Framework 2 tutorial far enough to get the Albums demo application running.

Then set up PD4ML's PHP wrapper against that application, as described in PHP Wrapper: download the wrapper package, unpack it into the application root, confirm a Java runtime is reachable from PHP, and run the bundled environment probe script to confirm everything is wired up. The unpacked wrapper should sit alongside the ZF2 application like this:

PD4ML PHP wrapper unpacked next to the ZF2 Albums application directory structure

Adding a "Page as PDF" button to a view

The example adds a "Page as PDF" button to the album list. As a feature this is mostly illustrative -- in a real deployment, you'd typically point the PD4ML converter directly at a known, print-optimized report or invoice URL rather than working out the current page's URL through an HTTP referrer, as this example does for generality.

1. Add a PDF-generation link to the album list view, module/Album/view/album/album/index.phtml:

...
</tr>
<?php endforeach; ?>
<!-- edit begin -->
<tr style="pd4ml-display: none">
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>
<a href="<?php echo $this->url('album', array('action'=>'pdf'));?>">Page as PDF</a>
</td>
</tr>
<!-- edit end -->
</table>

(The added section sits between the edit begin/edit end comments.) The pd4ml-display: none style hides the link itself from the generated PDF -- confirmed still supported in the current PD4ML CSS engine -- since a self-referential "convert to PDF" link makes no sense inside its own PDF output.

With the link in place, the album list looks like this, pointing at a new, not-yet-handled pdf action:

Album list view with the added "Page as PDF" link

2. Add the pdf action handler to module/Album/src/Album/Controller/AlbumController.php:

public function pdfAction()
{
	$url = $this->getRequest()->getHeader('Referer')->getUri();
	$enc = base64_encode($url);
	$this->redirect()->toUrl($this->getRequest()->getBaseUrl() . '/pd4ml.php?url=' . $enc);
}

The handler reads the referring page's URL -- the album list, in this case -- and forwards it to the converter script as a url parameter, base64-encoding it to sidestep any issues with special characters.

3. Create the converter script, public/pd4ml.php, which the redirect above targets:

<?php
$evaluation = 1;
$java = "java";

$url = base64_decode($_GET['url']) . '?layout=pdf';

if ( $evaluation == 1 ) {
	$jar = "../pd4ml_php_wrapper/pd4ml_demo.jar";
} else {
	$jar = "../pd4ml_php_wrapper/pd4ml.jar";
}

header("Pragma: cache");
header("Expires: 0");
header("Cache-control: private");
header('Content-type: application/pdf');
header('Content-disposition: inline');

if ( strpos(php_uname(), 'Windows' ) !== FALSE) {
	// server platform: Windows
	$jar = preg_replace('/\//', "\\\\", $jar);
	$cmdline = "$java -Xmx512m -jar $jar \"$url\" 800 A4";
} else {
	// server platform: UNIX-derived
	$cmdline = "$java -Xmx512m -Djava.awt.headless=true -jar $jar \"$url\" 800 A4";
}

// for the full current flag reference, see the Pd4Cmd Command-Line Reference page

passthru( $cmdline );

?>

Make sure there's no whitespace before <?php or after ?>.

The script decodes the url parameter, converts that URL to a PDF via Pd4Cmd, and streams the resulting bytes back as the HTTP response. It also appends a ?layout=pdf parameter to the URL before conversion, which the next step uses to signal the application to switch to a PDF-optimized layout.

4. Add a PDF-optimized layout template. The original album list view includes a navigation bar, which belongs in an interactive web page but adds nothing useful to a printed/PDF document. Copy module/Application/view/layout/layout.phtml to blank.phtml in the same directory, and strip the navigation bar out:

<?php echo $this->doctype(); ?>

<html lang="en">
<head>
<meta charset="utf-8">
<?php echo $this->headTitle('ZF2 '. $this->translate('Skeleton Application'))->setSeparator(' - ')->setAutoEscape(false) ?>

<?php echo $this->headMeta()->appendName('viewport', 'width=device-width, initial-scale=1.0') ?>

<!-- Le styles -->
<?php echo $this->headLink(array('rel' => 'shortcut icon', 'type' => 'image/vnd.microsoft.icon', 'href' => $this->basePath() . '/images/favicon.ico'))
->appendStylesheet($this->basePath() . '/css/bootstrap.min.css')
->appendStylesheet($this->basePath() . '/css/style.css')
->appendStylesheet($this->basePath() . '/css/bootstrap-responsive.min.css') ?>

<!-- Scripts -->
<?php echo $this->headScript()->appendFile($this->basePath() . '/js/html5.js', 'text/javascript', array('conditional' => 'lt IE 9',))
->appendFile($this->basePath() . '/js/jquery-1.7.2.min.js') ?>

</head>

<body>
<div class="container">
<br>
<?php echo $this->content; ?>
</div>
</body>
</html>

5. Register the new template in module/Album/config/module.config.php:

'view_manager' => array(
	'template_path_stack' => array(
		'album' => __DIR__ . '/../view',
	),
),
// edit begin
'template_map' => array(
	'layout/blank' => __DIR__ . '/../view/layout/blank.phtml',
),
// edit end

6. Switch templates based on the layout query parameter, in module/Album/src/Album/Controller/AlbumController.php's index action:

public function indexAction()
{
	// edit begin
	$flag = $this->params()->fromQuery('layout');
	if ('pdf' == $flag) {
		$layout = $this->layout();
		$layout->setTemplate('layout/blank');
	}
	// edit end

	return new ViewModel(array(
		'albums' => $this->getAlbumTable()->fetchAll(),
	));
}

With all six steps in place, clicking "Page as PDF" produces a navigation-free PDF like this example result.

The complete application structure (excluding the PD4ML PHP wrapper itself, which is covered separately in PHP Wrapper) is available as a downloadable archive. Remember to adjust the database credentials in config/autoload/local.php before running it.

Prerequisites

Adding a "Page as PDF" button to a view

See also