Syamantics.com

I have found some common code patterns/refactoring patterns while doing code reviewing in my current day job. And one of them involves switch blocks. After reading nate’s blog here about switch blocks, I thought to share something similar.

Following is an example code, where switch-case is used to configure some variables based on the value of $api_name.

swicth($api_name) {
	case 'flickr':
		$class = 'Phlickr';
		$subalbum = false;
		$auth = 'redirect';
		break;
	case 'photobucket':
		$class = 'PBAPI';
		$subalbum = true;
		$auth = 'redirect';
		break;
	case 'smugmug':
		$class = 'PHPSmug';
		$subalbum = false;
		$auth = 'direct';
		break;
	//
	//
}

This is a good-looking handsome piece of code, no doubt about that. But the following is a definite smarter one,

$api_settings = array(  'flickr' =>  array( 'class' => 'Phlickr', 'subalbum' => false, 'auth' => 'redirect' ),
				'photobucket' => array( 'class' => 'PBAPI', 'subalbum' => false, 'auth' => 'redirect' ),
				'smugmug' => array( 'class' => 'PHPSmug', 'subalbum' => false, 'auth' => 'direct' ),
				//
			);

if(isset($api_settings[$api_key])) extract($settings[$api_key]);

Design wise it is more flexible - you can just add an array in the $api_settings when a new api gets added to the list, it is slicker and handy when you have quite a few apis in your list. And performance wise, certainly hashes are faster than multiple conditional statements.

Another way to avoid dumb switch-cases/conditional statements can be using the dynamic features of PHP (+ some conventions). Let’s have a look at the following code that uses switch-case to determine the method to execute,

switch($type) {
  case 'users':
	$count = $this->__countUsers();
	break;
  case 'projects':
	$count = $this->__countPojects();
  case 'galleries':
	$count = $this->__countGalleries();
  case 'tags':
	$count = $this->__countTags();
  default:
	$count = 0;
}

We can convert it to something like this,

$count = 0;
$method = '__count'.ucwords($type);
if ( method_exists($this, $method) ) {
	$count = $this->$method();
}

We have reduced lines of code. And is not it much prettier? And now if we need to add a new type there, we can just add a method following the same convention.

Get rid of all your dumb conditionals… use PHP’s dynamic features ;)