Magic methods

There are several magic methods in PHP which save you time by limiting what code has to be written to access methods, getters and setters etc.

__get($val) allows you to have a get method on a class without actually creating a get method so.

Notice how we ensure we don't try to return a variable if the variable requested is empty, this ensures that we don't try to get a variable that won't exist.

When a get or set is called on a class, PHP looks to see if there is a explicitly defined property which is visible before calling a magic __get or __set method.

class Example
{
private $counter;
private $name;
private $age;

function __get($var)
{
  if (!empty($var))
  {
   return $this->$var;
  }
}
}

This will mean that the below code will get the private variables without any getters needing to be written in the class.

$example = new Example();
$example->name;
$example->counter;

Unfortunatley it also allowed us to access counter which, should be kept internal to the class. A better way therefore of doing this is.

class Example
{
private $counter;
private $vars;

function __get($var)
{
  if (!empty($var) && !empty($vars[$var]))
  {
   return $this->$vars[$var];
  }
}
}

This will then ensure that values are only read from the private array and no other private variables are exposed. __set() is quite similar to __get except that it is a setter rather than a getter. This will set a value in the following way.

class Example
{
private $name;

function __set($var, $value)
{
  if (!empty($var))
  {
   $this->$var = $value;
  }
}
}

This can be used in the following way:

$example = new Example();
$example->name = 'Dominic';

Again a private array could be used to protect the protection of the other variables in the class.

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Written by Dominic Skinner
Last Updated: 2011-10-25 16:00:38