Tag Archives: Computer file formats

Media RSS and ZF – Part 2

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Here’s the promised chunk of code making the most simple bridge between Zend Framework and Media RSS.

Step 1

Just add a simple action in a controller:

class IndexController extends Zend_Controller_Action
{
	public function indexAction()
	{
	    $this->getResponse()->setHeader('Content-Type', 'application/xml');
	    $this->view->somevar = 'some value';
 
	    echo $this->view->render('index/index.xml');
 
	    $this->_helper->layout()->disableLayout();
	    $this->_helper->viewRenderer->setNoRender(true);
	}
}

Step 2

After you’ve setup the xml file as a view script – you can simply access it as a normal Zend Framework view:

<rss version="2.0" xmlns:media="http://search.yahoo.com/mrss/" xmlns:av="http://www.searchvideo.com/schemas/av/1.0">
  <channel>
   <title><?php echo $this->somevar ?></title>
   ...
   other media rss elements
   ...
</channel>
</rss>

Zend Framework and Media RSS

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The Problem

Since native RSS format is not designed to deliver media content, there is a need for newer format supporting video and audio. There is such format – Media RSS introduced by Yahoo! in 2004. Actually now RSS supports some king of pseudo audio and video with the enclosure tag.

Inserting Media In RSS with Media RSS

Although there is a standardized format, there is not a Zend Framework native module. There is however a proposal, but that’s far not enough.

Possible Solutions

For me there are two possible solutions. The first is writing Zend_Feed_Mrss and extend the Zend_Feed_Rss functionality, but that appears to be a non-trivial task. The second solution is to write custom view returning XML, which I’m choosing for now. I hope I can paste some code soon!

Download Files with Zend Framework

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Download a File

The title may sound unclear enough, but the task is simple. You’ve to make a file download process within a Zend Framework’s controller. Let’s assume we’ve the DownloadController setup:

<?php
 
class DownloadController extends Zend_Controller_Action
{
	public function indexAction()
	{}	
}

In PHP there are at least three simple lines of code that will do the job of downloading a file.

header('Content-Type: image/jpeg');
header('Content-Disposition: attachment; filename="logo.jpg"');
readfile('images/logo.jpg');

Note that here there is a content-type header, which is important cause the browsers understands what kind of file is supposed to be downloaded. The second line suggests a name of the downloaded file and the third one returns the file to the client.

Download a File … within Zend Framework

Those three lines wont work alone in a ZF application, because there’s no view, but even if you create a .phtml (view) file for this action it won’t work, because the header of the returned file is modified.

The question is how to possibly return the file for download, perhaps write some statistics to the database and if there’s a problem (some permission issues for instance) return a message to the user.

The Basic Solution

The solution is simple. First make it work by disabling the view and possibly the layout for this action:

public function indexAction()
{
	header('Content-Type: image/jpeg');
	header('Content-Disposition: attachment; filename="logo.jpg"');
	readfile('images/logo.jpg');
 
	// disable the view ... and perhaps the layout
	$this->view->layout()->disableLayout();
        $this->_helper->viewRenderer->setNoRender(true);
}

Than add some code where you can check the permissions. Just because there’s no view for this action you can redirect to another – errorAction():

public function indexAction()
{
    if (userHasNoPermissions) {
        $this->view->msg = 'This file cannot be downloaded!';
        $this->_forward('error', 'download');
    }
 
    header('Content-Type: image/jpeg');
    header('Content-Disposition: attachment; filename="logo.jpg"');
    readfile('images/logo.jpg');
 
    // disable layout and view
    $this->view->layout()->disableLayout();
    $this->_helper->viewRenderer->setNoRender(true);
}

But that still will prompt you a file to download, so there should be a return statement that will return false:

public function indexAction()
{
    if (userHasNoPermissions) {
        $this->view->msg = 'This file cannot be downloaded!';
        $this->_forward('error', 'download');
        return FALSE;
    }
 
    header('Content-Type: image/jpeg');
    header('Content-Disposition: attachment; filename="logo.jpg"');
    readfile('images/logo.jpg');
 
    // disable layout and view
    $this->view->layout()->disableLayout();
    $this->_helper->viewRenderer->setNoRender(true);
}

So here’s the complete source of DownloadController.php:

<?php
 
class DownloadController extends Zend_Controller_Action
{
	public function indexAction()
	{
	    if (userHasNoPermissions) {
	        $this->view->msg = 'This file cannot be downloaded!';
	        $this->_forward('error', 'download');
	        return FALSE;
	    }
 
	    header('Content-Type: image/jpeg');
	    header('Content-Disposition: attachment; filename="logo.jpg"');
	    readfile('images/logo.jpg');
 
	    // disable layout and view
	    $this->view->layout()->disableLayout();
	    $this->_helper->viewRenderer->setNoRender(true);
	}	
 
	public function errorAction()
	{}
}

and the error.phtml:

<?php echo $this->msg ?>