Category Archives: micro tutorial

Setting Up a Specific Layout for a Zend Action

micro tutorial, PHP, zend framework, , ,

Now that’s really simple! In your action method simply add this line:

$this->view->layout()->setLayout('embed');

Thus the code will look like so:

<?php
 
class IndexController extends Zend_Controller_Action
{
	public function indexAction()
	{
		$this->view->layout()->setLayout('embed');
		// ...	
	}	
}

Download Files with Zend Framework

micro tutorial, PHP, zend framework, , , , , , , , ,

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 ?>

PHP Coding Style: Large IF Statements

micro tutorial, PHP, , , , , , , ,

Have you ever seen some PHP code like that:

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if ($condition1 && $condition2 && $string1 == $string2 . $string3 && $string4 != $string5 . $string6) {
   // write some code here!?
}

It is ugly, isn’t it?

I’d prefer to make it clearer! What about that?

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if ($condition1 
   && $condition2
   && $string1 == $string2
                . $string3
   && $string4 != $string5
                . $string6
) {
   // write some code here
}

JavaScript Objects Coding Style

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JavaScript vs. PHP

Continuing from my post about PHP arrays coding style and following the comments of that post, I’d like to write a bit about JavaScript objects’ coding style.

You perhaps know that the term object is quite undefined or under estimated in the JavaScript world, but I’d speak about the key/value pairs in JS commonly formatted like that:

var obj = { key : 'value' }

Here you can add more and more key/value pairs, but what’s different from the PHP associative arrays and what’s the same and should be cosidered.

The Same as PHP?

I wrote about the alignment in PHP and hashes. Than I showed how I align them:

$arr = array(
   'short'   => 'val',
   'longkey' => 'val'
);

In JavaScript you should use the same technique of alignment:

var obj = {
   'short'   : 'val',
   'longkey' : 'val'
};

Some Differences

Yes, there are more differences, which is normal. First of all you don’t have the => notation in JavaScript and a : is used. Second and most important you cannot add a trailing comma after the last key/value pair. Note that in PHP that’s fine!

// that will throw an error in MSIE
var obj = {
   'short'   : 'val',
   'longkey' : 'val',
};

while this is OK in PHP and it’s encouraged:

$arr = array(
   'short'   => 'val',
   'longkey' => 'val',
);

PHP Functions: realpath()

micro tutorial, PHP, , , , , , , ,

Watch Out – Hard Code

Perhaps every developer knows that hard coded paths are no good! The code’s good to be flexible and extensible, but what the way to achieve that? In a typically developed application you’re completely sure the way the folders are nested will be permanent and no change will occur, and that’s maybe true, but however don’t be completely sure.

An Example

Let’s take a typical example. You’ve to access a uploaded file with PHP. By default the files are uploaded in the /tmp folder with PHP given name. That’s why immediately after the upload (the form submit) you’ve to process the _POST and the _FILES arrays and perhaps move the uploaded file somewhere else.

However you’d like to access this file wherever the application is – on the production servers or on the development server or even on the localhost!

I ran into that kind of problem/task. The thing I’d like to achieve was a bit different. I constructed the path with the dirname() function, but there were still ‘/../../’ chunks in it. So the solution is the realpath() function that removes those chunks and converts the path into one “calculated” real path to the file.

Let me show you an example:

// get the uploaded file path
$scriptPath = dirname(__FILE__);
 
// get the realpath to avoid the /../ part of the path
// with dirname they remain in the path
$uploadFolderPath = realpath($scriptPath . '/../../folder_name/');

If you were using dirname() you’d get something like that:

/folder1/folder2/folder3/../../folder2/file.txt

Now with realpath() the result is:

/folder1/folder2/file.txt

That’s more clear and even both are working correctly I’d prefer the second one!