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();

?>

Output

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

<?php

class MagicMethod {
    function __destruct() {
        echo "This destruct magic method "
        + "gets called when object destroys";
    }
}

$obj = new MagicMethod();

?>

Output

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

<?php

class 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");

?>

Output

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

<?php

class MagicMethod {
    function __toString(){
        return "You are using MagicMethod object as a String ";
    }
}

$obj = new MagicMethod();

echo $obj;

?>

Output

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

<?php

class MagicMethod {
    function __get($name){
        echo "You are trying to get '" . $name .
          "' which is either inaccessible
           or non existing member";
    }
}

$obj = new MagicMethod();
$obj->value;

?>

Output

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

<?php

class 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";

?>

Output

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

<?php

class MagicMethod {
    function __debugInfo(){
        return array("variable"=> "value");
    }
}

$obj = new MagicMethod();
var_dump($obj);

?>

Output

object(MagicMethod)#1 (1) {
  ["variable"]=>
  string(5) "value"
}