What are magic methods and how to use them in PHP ?
PHP magic methods are special methods that are called automatically when certain conditions are met. There are several magic methods in PHP. Every magic method follows certain rules –
- Every magic method starts with a double underscore ( __ ).
- They are predefined and neither can be created nor removed.
- Magic methods have reserved names and their name should not be used for other purposes.
- Magic methods are automatically called when certain criteria are met.
| Method Names | Return types | Condition of calling |
| __construct() | NaN |
This method gets called automatically every time the object of a particular class is created. The function of this magic method is the same as the constructor in any OOP language. |
| __destruct() | NaN |
As the name suggests this method is called when the object is destroyed and no longer in use. Generally at the end of the program and end of the function. |
| __call($name,$parameter) | Not mandatory | This method executes when a method is called which is not defined yet. |
| __toString() | String |
This method is called when we need to convert the object into a string. For example: echo $obj; The $obj->__toString(); will be called magically. |
| __get($name) | NaN | This method is called when an inaccessible variable or non-existing variable is used. |
| __set($name , $value) | NaN | This method is called when an inaccessible variable or non-existing variable is written. |
| __debugInfo() | array | This magic method is executed when an object is used inside var_dump() for debugging purposes. |
The following are code snippets and examples to understand magic methods better.
__construct() Method: In the below example, the MagicMethod class has a magic method __construct() and it is called every time when a new object of MagicMethod class is created.
PHP
<?php class MagicMethod { function __construct() { echo "This is the construct magic method"; }}// Creating object of Magic method class$obj = new MagicMethod(); ?> |
This is the construct magic method
__destruct() Method: In the below example, the MagicMethod class has a magic method __destruct() that gets called automatically when the object of MagicMethod destroys.
PHP
<?phpclass MagicMethod { function __destruct() { echo "This destruct magic method " + "gets called when object destroys"; }}$obj = new MagicMethod();?> |
This destruct magic method gets called when object destroys
__call($name, $parameters) Method: This method gets called when a method or property is called which has not been defined.
This method takes two parameters:
- $name: This contains the name of the method which was called.
- $parameters: This is an array of parameters that were given to that method.
PHP
<?phpclass MagicMethod { function __call($name , $parameters){ echo "Name of method =>" . $name."\n"; echo "Parameters provided\n"; print_r($parameters); }}// Instantiating MagicMethod$obj = new MagicMethod();$obj->hello("Magic" , "Method");?> |
Name of method =>hello
Parameters provided
Array
(
[0] => Magic
[1] => Method
)
__toString() Method: This method gets called when an object is treated as a string. This method is also useful to represent an object as a String.
PHP
<?phpclass MagicMethod { function __toString(){ return "You are using MagicMethod object as a String "; }}$obj = new MagicMethod();echo $obj;?> |
You are using MagicMethod object as a String
__get($name) Method: This method gets called when an inaccessible (private or protected ) variable or non-existing variables are used.
PHP
<?phpclass MagicMethod { function __get($name){ echo "You are trying to get '" . $name . "' which is either inaccessible or non existing member"; }}$obj = new MagicMethod();$obj->value;?> |
You are trying to get 'value' which is either inaccessible or non existing member
__set($name, $value) Method: This method is called when an inaccessible variable or non-existing variable is tried to modify or alter.
PHP
<?phpclass MagicMethod { function __set($name , $value) { echo "You are trying to modify '" . $name . "' with '" . $value . "' which is either inaccessible or non-existing member"; }}$obj = new MagicMethod();$obj->value = "Hello";?> |
You are trying to modify 'value' with 'Hello' which is either inaccessible
or non-existing member
__debugInfo() Method: This method is used when the var_dump() function is called with object as a parameter. This method should return an array containing all the variables which may be useful in debugging.
PHP
<?phpclass MagicMethod { function __debugInfo(){ return array("variable"=> "value"); }}$obj = new MagicMethod();var_dump($obj);?> |
object(MagicMethod)#1 (1) {
["variable"]=>
string(5) "value"
}
