Magic Methods

The function names __construct(), __destruct(), __call(), __callStatic(), __get(), __set(), __isset(), __unset(), __sleep(), __wakeup(), __toString(), __invoke(), __set_state() and __clone() are magical in PHP classes. You cannot have functions with these names in any of your classes unless you want the magic functionality associated with them.

Caution

PHP reserves all function names starting with __ as magical. It is recommended that you do not use function names with __ in PHP unless you want some documented magic functionality.

__sleep() and __wakeup()

public array __sleep ( void )
void __wakeup ( void )

serialize() checks if your class has a function with the magic name __sleep(). If so, that function is executed prior to any serialization. It can clean up the object and is supposed to return an array with the names of all variables of that object that should be serialized. If the method doesn't return anything then NULL is serialized and E_NOTICE is issued.

Note:

It is not possible for __sleep() to return names of private properties in parent classes. Doing this will result in an E_NOTICE level error. Instead you may use the Serializable interface.

The intended use of __sleep() is to commit pending data or perform similar cleanup tasks. Also, the function is useful if you have very large objects which do not need to be saved completely.

Conversely, unserialize() checks for the presence of a function with the magic name __wakeup(). If present, this function can reconstruct any resources that the object may have.

The intended use of __wakeup() is to reestablish any database connections that may have been lost during serialization and perform other reinitialization tasks.

Example #1 Sleep and wakeup

<?php
class Connection
{
    protected 
$link;
    private 
$dsn$username$password;
    
    public function 
__construct($dsn$username$password)
    {
        
$this->dsn $dsn;
        
$this->username $username;
        
$this->password $password;
        
$this->connect();
    }
    
    private function 
connect()
    {
        
$this->link = new PDO($this->dsn$this->username$this->password);
    }
    
    public function 
__sleep()
    {
        return array(
'dsn''username''password');
    }
    
    public function 
__wakeup()
    {
        
$this->connect();
    }
}
?>

__toString()

public string __toString ( void )

The __toString() method allows a class to decide how it will react when it is treated like a string. For example, what echo $obj; will print. This method must return a string, as otherwise a fatal E_RECOVERABLE_ERROR level error is emitted.

Warning

You cannot throw an exception from within a __toString() method. Doing so will result in a fatal error.

Example #2 Simple example

<?php
// Declare a simple class
class TestClass
{
    public 
$foo;

    public function 
__construct($foo)
    {
        
$this->foo $foo;
    }

    public function 
__toString()
    {
        return 
$this->foo;
    }
}

$class = new TestClass('Hello');
echo 
$class;
?>

The above example will output:

Hello

It is worth noting that before PHP 5.2.0 the __toString() method was only called when it was directly combined with echo or print. Since PHP 5.2.0, it is called in any string context (e.g. in printf() with %s modifier) but not in other types contexts (e.g. with %d modifier). Since PHP 5.2.0, converting objects without __toString() method to string would cause E_RECOVERABLE_ERROR.

__invoke()

mixed __invoke ([ $... ] )

The __invoke() method is called when a script tries to call an object as a function.

Note:

This feature is available since PHP 5.3.0.

Example #3 Using __invoke()

<?php
class CallableClass
{
    public function 
__invoke($x)
    {
        
var_dump($x);
    }
}
$obj = new CallableClass;
$obj(5);
var_dump(is_callable($obj));
?>

The above example will output:

int(5)
bool(true)

__set_state()

static object __set_state ( array $properties )

This static method is called for classes exported by var_export() since PHP 5.1.0.

The only parameter of this method is an array containing exported properties in the form array('property' => value, ...).

Example #4 Using __set_state() (since PHP 5.1.0)

<?php

class A
{
    public 
$var1;
    public 
$var2;

    public static function 
__set_state($an_array// As of PHP 5.1.0
    
{
        
$obj = new A;
        
$obj->var1 $an_array['var1'];
        
$obj->var2 $an_array['var2'];
        return 
$obj;
    }
}

$a = new A;
$a->var1 5;
$a->var2 'foo';

eval(
'$b = ' var_export($atrue) . ';'); // $b = A::__set_state(array(
                                            //    'var1' => 5,
                                            //    'var2' => 'foo',
                                            // ));
var_dump($b);

?>

The above example will output:

object(A)#2 (2) {
  ["var1"]=>
  int(5)
  ["var2"]=>
  string(3) "foo"
}

Коментарии

One of the principles of OOP is encapsulation--the idea that an object should handle its own data and no others'.  Asking base classes to take care of subclasses' data, esp considering that a class can't possibly know how many dozens of ways it will be extended, is irresponsible and dangerous.

Consider the following...

<?php
class SomeStupidStorageClass
{
  public function 
getContents($pos$len) { ...stuff... }
}

class 
CryptedStorageClass extends SomeStupidStorageClass
{
  private 
$decrypted_block;
  public function 
getContents($pos$len) { ...decrypt... }
}
?>

If SomeStupidStorageClass decided to serialize its subclasses' data as well as its own, a portion of what was once an encrypted thingie could be stored, in the clear, wherever the thingie was stored.  Obviously, CryptedStorageClass would never have chosen this...but it had to either know how to serialize its parent class's data without calling parent::_sleep(), or let the base class do what it wanted to.

Considering encapsulation again, no class should have to know how the parent handles its own private data.  And it certainly shouldn't have to worry that users will find a way to break access controls in the name of convenience.

If a class wants both to have private/protected data and to survive serialization, it should have its own __sleep() method which asks the parent to report its own fields and then adds to the list if applicable.  Like so....

<?php

class BetterClass
{
  private 
$content;

  public function 
__sleep()
  {
    return array(
'basedata1''basedata2');
  }

  public function 
getContents() { ...stuff... }
}

class 
BetterDerivedClass extends BetterClass
{
  private 
$decrypted_block;

  public function 
__sleep()
  {
    return 
parent::__sleep();
  }

  public function 
getContents() { ...decrypt... }
}

?>

The derived class has better control over its data, and we don't have to worry about something being stored that shouldn't be.
2005-01-27 01:09:17
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Intriguing what happens when __sleep() and __wakeup() and sessions() are mixed. I had a hunch that, as session data is serialized, __sleep would be called when an object, or whatever, is stored in _SESSION. true. The same hunch applied when session_start() was called. Would __wakeup() be called? True. Very helpful, specifically as I'm building massive objects (well, lots of simple objects stored in sessions), and need lots of automated tasks (potentially) reloaded at "wakeup" time. (for instance, restarting a database session/connection).
2005-08-13 21:26:21
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
When you use sessions, its very important to keep the sessiondata small, due to low performance with unserialize. Every class shoud extend from this class. The result will be, that no null Values are written to the sessiondata. It will increase performance.

<?
class BaseObject
{
    function 
__sleep()
    {
       
$vars = (array)$this;
        foreach (
$vars as $key => $val)
        {
            if (
is_null($val))
            {
                unset(
$vars[$key]);
            }
        }   
        return 
array_keys($vars);
    }
};
?>
2005-08-15 07:47:24
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Автор:
about __sleep and _wakeup, consider using a method like this:

class core
{

 var $sub_core; //ref of subcore
 var $_sleep_subcore; // place where serialize version of sub_core will be stored

 function core(){
  $this->sub_core = new sub_core();
  return true;
 }

 function __wakeup()
 {
  // on wakeup of core, core unserializes sub_core
  // wich it had stored when it was serialized itself
  $this->sub_core = unserialize($this->_sleep_subcore);
  return true;
 }

 function __sleep()
 {
  // sub_core will be serialized when core is serialized.
  // the serialized subcore will be stored as a string inside core.
   $this->_sleep_subcore = serialize($this->sub_core);
   $return_arr[] = "_sleep_subcore";
   return $return_arr;
 }

}

class sub_core
{
 var $info;

 function sub_core()
 {
  $this->info["somedata"] = "somedata overhere"
 }

 function __wakeup()
 {
  return true;
 }

 function __sleep()
 {
  $return_arr[] = "info"
  return $return_arr; 
 }

}

this way subcore is being serialized by core when core is being serialized. subcore handles its own data and core stores it as a serialize string inside itself. on wakeup core unserializes subcore. 

this may have a performance cost, but if you have many objects connected this way this is the best way of serializing them. you only need to serialize the the main object wich will serialize all those below which will serialize all those below them again. in effect causing a sort of chainreaction in wich each object takes care of its own info.

offcoarse you always need to store the eventualy serialized string in a safe place. somebody got experience with this way of __wakeup and __sleep. 

works in PHP4&5
2005-12-09 10:44:36
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Автор:
If you use the Magical Method '__set()', be shure that the call of
<?php
$myobject
->test['myarray'] = 'data';
?>
will not appear!

For that u have to do it the fine way if you want to use __set Method ;)
<?php
$myobject
->test = array('myarray' => 'data');
?>

If a Variable is already set, the __set Magic Method already wont appear!

My first solution was to use a Caller Class.
With that, i ever knew which Module i currently use!
But who needs it... :]
There are quiet better solutions for this...
Here's the Code:

<?php
class Caller {
    public 
$caller;
    public 
$module;

    function 
__call($funcname$args = array()) {
       
$this->setModuleInformation();

        if (
is_object($this->caller) && function_exists('call_user_func_array'))
           
$return call_user_func_array(array(&$this->caller$funcname), $args);
        else
           
trigger_error("Call to Function with call_user_func_array failed"E_USER_ERROR);
       
       
$this->unsetModuleInformation();
        return 
$return;
    }

    function 
__construct($callerClassName false$callerModuleName 'Webboard') {
        if (
$callerClassName == false)
           
trigger_error('No Classname'E_USER_ERROR);

       
$this->module $callerModuleName;

        if (
class_exists($callerClassName))
           
$this->caller = new $callerClassName();
        else
           
trigger_error('Class not exists: \''.$callerClassName.'\''E_USER_ERROR);

        if (
is_object($this->caller))
        {
           
$this->setModuleInformation();
            if (
method_exists($this->caller'__init'))
               
$this->caller->__init();
           
$this->unsetModuleInformation();
        }
        else
           
trigger_error('Caller is no object!'E_USER_ERROR);
    }

    function 
__destruct() {
       
$this->setModuleInformation();
        if (
method_exists($this->caller'__deinit'))
           
$this->caller->__deinit();
       
$this->unsetModuleInformation();
    }

    function 
__isset($isset) {
       
$this->setModuleInformation();
        if (
is_object($this->caller))
           
$return = isset($this->caller->{$isset});
        else
           
trigger_error('Caller is no object!'E_USER_ERROR);
       
$this->unsetModuleInformation();
        return 
$return;
    }

    function 
__unset($unset) {
       
$this->setModuleInformation();
        if (
is_object($this->caller)) {
            if (isset(
$this->caller->{$unset}))
                unset(
$this->caller->{$unset});
        }
        else
           
trigger_error('Caller is no object!'E_USER_ERROR);
       
$this->unsetModuleInformation();
    }

    function 
__set($set$val) {
       
$this->setModuleInformation();
        if (
is_object($this->caller))
           
$this->caller->{$set} = $val;
        else
           
trigger_error('Caller is no object!'E_USER_ERROR);
       
$this->unsetModuleInformation();
    }

    function 
__get($get) {
       
$this->setModuleInformation();
        if (
is_object($this->caller)) {
            if (isset(
$this->caller->{$get}))
               
$return $this->caller->{$get};
            else
               
$return false;
        }
        else
           
trigger_error('Caller is no object!'E_USER_ERROR);
       
$this->unsetModuleInformation();
        return 
$return;
    }
   
    function 
setModuleInformation() {
       
$this->caller->module $this->module;
    }

    function 
unsetModuleInformation() {
       
$this->caller->module NULL;
    }
}

// Well this can be a Config Class?
class Config {
    public 
$module;

    public 
$test;

    function 
__construct()
    {
        print(
'Constructor will have no Module Information... Use __init() instead!<br />');
        print(
'--> '.print_r($this->module1).' <--');
        print(
'<br />');
        print(
'<br />');
       
$this->test '123';
    }
   
    function 
__init()
    {
        print(
'Using of __init()!<br />');
        print(
'--> '.print_r($this->module1).' <--');
        print(
'<br />');
        print(
'<br />');
    }
   
    function 
testFunction($test false)
    {
        if (
$test != false)
           
$this->test $test;
    }
}

echo(
'<pre>');
$wow = new Caller('Config''Guestbook');
print_r($wow->test);
print(
'<br />');
print(
'<br />');
$wow->test '456';
print_r($wow->test);
print(
'<br />');
print(
'<br />');
$wow->testFunction('789');
print_r($wow->test);
print(
'<br />');
print(
'<br />');
print_r($wow->module);
echo(
'</pre>');
?>

Outputs something Like:

Constructor will have no Module Information... Use __init() instead!
-->  <--

Using of __init()!
--> Guestbook <--

123

456

789

Guestbook
2006-04-02 12:55:21
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
The above hint for using array_keys((array)$obj) got me investigating how to get __sleep to really work with object hierarchies.

With PHP 5.2.3, If you want to serialize an object that is part of an object hierarchy and you want to selectively serialize members (public, private, and protected) by manually specifying the array of members, there are a few simple rules for naming members that you must follow:

1. public members should be named using just their member name, like so:

<?php
class Foo {
    public 
$bar;

    public function 
__sleep() {
        return array(
"bar");
    }
}
?>

2. protected members should be named using "\0" . "*" . "\0" . member name, like so:

<?php
class Foo {
    protected 
$bar;

    public function 
__sleep() {
        return array(
"\0*\0bar");
    }
}
?>

3. private members should be named using "\0" . class name . "\0" . member name, like so:

<?php
class Foo {
    private 
$bar;

    public function 
__sleep() {
        return array(
"\0Foo\0bar");
    }
}
?>

So with this information let us serialize a class hierarchy correctly:

<?php

class Base {
    private 
$foo "foo_value";
    protected 
$bar "bar_value";

    public function 
__sleep() {
        return array(
"\0Base\0foo""\0*\0bar");
    }
}

class 
Derived extends Base {
    public 
$baz "baz_value";
    private 
$boo "boo_value";

    public function 
__sleep() {
       
// we have to merge our members with our parent's
       
return array_merge(array("baz""\0Derived\0boo"), parent::__sleep());
    }
}

class 
Leaf extends Derived {
    private 
$qux "qux_value";
    protected 
$zaz "zaz_value";
    public 
$blah "blah_value";

    public function 
__sleep() {
       
// again, merge our members with our parent's
       
return array_merge(array("\0Leaf\0qux""\0*\0zaz""blah"), parent::__sleep());
    }
}

// test it
$test = new Leaf();
$s serialize($test);
$test2 unserialize($s);
echo 
$s;
print_r($test);
print_r($test2);

?>

Now if you comment out all of the __sleep() functions and output the serialized string, you will see that the output doesn't change.  The most important part of course is that with the proper __sleep() functions, we can unserialize the string and get a properly set up object.

I hope this solves the mystery for everybody.  __sleep() does work, if you use it correctly :-)
2008-02-29 20:22:27
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Maybe we can using unserialize() & __wakeup() instead "new" when creating a new instance of class.

Consider following codes:

class foo
{
    static public $WAKEUP_STR = 'O:3:"foo":0:{}';
    public function foo(){}
    public function bar(){}
}

$foo = unserialize(foo::$WAKEUP_STR);
2008-05-10 09:24:09
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Автор:
Serializing objects is problematic with references. This is solved redefining the __sleep() magic method. This is also problematic when parent class has private variables since the parent object is not accessible nor its private variables from within the child object.

I found a solution that seems working for classes that implements this __sleep() method, and for its subclasses. Without more work in subclasses. The inheritance system does the trick.

Recursively __sleep() call parent' __sleep() and return the whole array of variables of the object instance to be serialized.

<?php
class foo {
}

class 
{
  private 
$var1;

  function 
__construct(foo &$obj NULL) {
   
$this->var1 = &$obj;
  }

 
/** Return its variables array, if its parent exists and the __sleep method is accessible, call it and push the result into the array and return the whole thing. */
 
public function __sleep() {
   
$a array_keys(get_object_vars(&$this));
    if (
method_exists(parent'__sleep')) {
     
$p parent::__sleep();
     
array_push($a$p);
    };
    return 
$a;
  }
}

class 
extends {
  function 
__construct(foo &$obj NULL) {
   
parent::__construct($obj);
  }
}

session_start();
$myfoo = &new foo();
$myb = &new b($myfoo);
$myb unserialize(serialize(&$myb));
?>

This should work, I haven't tested deeper.
2008-05-31 19:24:37
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
The __toString() method is extremely useful for converting class attribute names and values into common string representations of data (of which there are many choices). I mention this as previous references to __toString() refer only to debugging uses.

I have previously used the __toString() method in the following ways:

 - representing a data-holding object as:
   - XML
   - raw POST data
   - a GET query string
   - header name:value pairs

 - representing a custom mail object as an actual email (headers then body, all correctly represented)

When creating a class, consider what possible standard string representations are available and, of those, which would be the most relevant with respect to the purpose of the class.

Being able to represent data-holding objects in standardised string forms makes it much easier for your internal representations of data to be shared in an interoperable way with other applications.
2008-10-03 10:26:53
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Be very careful to define __set_state() in classes which inherit from a parent using it, as the static __set_state() call will be called for any children.  If you are not careful, you will end up with an object of the wrong type.  Here is an example:

<?php
class A
{
    public 
$var1

    public static function 
__set_state($an_array)
    {
       
$obj = new A;
       
$obj->var1 $an_array['var1']; 
        return 
$obj;
    }
}

class 
extends {
}

$b = new B;
$b->var1 5;

eval(
'$new_b = ' var_export($btrue) . ';'); 
var_dump($new_b);
/*
object(A)#2 (1) {
  ["var1"]=>
  int(5)
}
*/
?>
2008-12-03 16:01:49
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Note also that the constructor is executed also, and before __set_state(), making this magic function less magic, imho, (except for the ability to assign private members).
2009-04-09 09:35:55
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Автор:
Concerning __set() with protected/private/overloaded properties, the behavior might not be so intuitive without knowing some underlying rules.  Consider this test object for the following examples...

<?php
class {
    protected 
$test_int 2;
    protected 
$test_array = array('key' => 'test');
    protected 
$test_obj;
   
    function 
__construct() {
       
$this->test_obj = new stdClass();
        }
       
    function 
__get($prop) {
        return 
$this->$prop;
        }
       
    function 
__set($prop$val) {
       
$this->$prop $val;
        }
    }

$a = new A();

?>

Combined Operators (.=, +=, *=, etc): you must also define a companion __get() method to grant write -and- read access to the property.  Remember, "$x += $y" is shorthand for "$x = $x + $y".  In other words, "__set($x, (__get($x) + $y))".

Properties that are Arrays: attempting to set array values like "$a->test_array[] = 'asdf';" from outside this object will result in an "Indirect modification of overloaded property" notice and the operation completely ignored.  You can't use '[]' for array value assignment in this context (with the exception only if you made __get() return by reference, in which case, it would work fine and bypass the __set() method altogether).  You can work around this doing something like unioning the array instead:

<?php

$a
->test_array[] = 'asdf'// notice given and ignored unless __get() was declared to return by reference
$a->test_array += array(=> 'asdf'); // to add a key/value
$a->test_array = array("key" => 'asdf') + $a->test_array// to overwrite a  key/value.

?>

Properties that are Objects: as long as you have that __get() method, you can freely access and alter that sub object's own properties, bypassing __set() entirely.  Remember, objects are assigned and passed by reference naturally. 

<?php

$a
->test_obj->prop 1// fine if $a did not have a set method declared.

?>

All above tested in 5.3.2.
2010-07-24 22:41:41
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Автор:
Warning __toString can be triggerd more then one time

<?php
if(strstr(substr($obj,0,1024), 'somestuff')
    echo 
$obj;
return 
'missing somestuff at the start, create container!';

substr() will trigger a __toString aswell as echo $obj;
?>

wich cause a performance issue since it will gather all data twice.

what i used as a hotfix:

<?php
__toString
(){
  if(
null === $this->sToString)
     
$this->sToString $this->_show();
  return 
$this->sToString;
}
?>
2011-05-25 15:10:40
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Invoking a class inside a class results in an error.

<?php
class A
{
    public function 
__invoke()
    {
        echo 
"Invoking A() Class";
    }
}

class 

{
    public 
$a;
   
    public function 
__construct()
    {
       
$this->= new A();
    }
   
    public function 
__invoke()
    {
        echo 
"Invoking B() Class";
    }
}

$a = new A();
$b = new B();
$a();
$b();
$b->a();

?>

returns
Invoking B() Class
PHP Fatal error:  Call to undefined method B::a()
2011-12-29 23:42:17
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Ever wondered why you can't throw exceptions from __toString()? Yeah me too. 

Well now you can! This trick allows you to throw any type of exception from within a __toString(), with a full & correct backtrace.

How does it work? Well PHP __toString() handling is not as strict in every case: throwing an Exception from __toString() triggers a fatal E_ERROR, but returning a non-string value from a __toString() triggers a non-fatal E_RECOVERABLE_ERROR. 
Add a little bookkeeping, and can circumvented this PHP deficiency!
(tested to work PHP 5.3+)

<?php

set_error_handler
(array('My_ToStringFixer''errorHandler'));
error_reporting(E_ALL E_STRICT);

class 
My_ToStringFixer
{
    protected static 
$_toStringException;

    public static function 
errorHandler($errorNumber$errorMessage$errorFile$errorLine)
    {
        if (isset(
self::$_toStringException))
        {
           
$exception self::$_toStringException;
           
// Always unset '_toStringException', we don't want a straggler to be found later if something came between the setting and the error
           
self::$_toStringException null;
            if (
preg_match('~^Method .*::__toString\(\) must return a string value$~'$errorMessage))
                throw 
$exception;
        }
        return 
false;
    }
   
    public static function 
throwToStringException($exception)
    {
       
// Should not occur with prescribed usage, but in case of recursion: clean out exception, return a valid string, and weep
       
if (isset(self::$_toStringException))
        {
           
self::$_toStringException null;
            return 
'';
        }

       
self::$_toStringException $exception;

        return 
null;
    }
}

class 
My_Class
{
    public function 
doComplexStuff()
    {
        throw new 
Exception('Oh noes!');
    }

    public function 
__toString()
    {
        try
        {
           
// do your complex thing which might trigger an exception
           
return $this->doComplexStuff();
        }
        catch (
Exception $e)
        {
           
// The 'return' is required to trigger the trick
           
return My_ToStringFixer::throwToStringException($e);
        }
    }
}

$x = new My_Class();

try
{
    echo 
$x;
}
catch (
Exception $e)
{
    echo 
'Caught Exception! : '$e;
}
?>
2012-02-14 12:54:16
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
To avoid instanciating the parent instead of the inherited class for __set_state() as reported by jsnell, you could use late static binding introduced in PHP 5.3:

<?php
class {
    public static function 
__set_state($data) {
        return new static();
    }
}

class 
extends {
}

$instance = new B();
eval(
'$test = ' var_export($instancetrue) . ';');
var_dump($test);
// -> object(B)#2 (0) {
// }
?>
2013-05-16 09:08:50
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
A simple API wrapper, using __call() and the PHP 5.6 "..." token.
http://php.net/manual/functions.arguments.php#functions.variable-arg-list

<?php
namespace Example;

use 
Exception;
use 
ReflectionClass;
use 
SomeApiInterface;
use 
SomeHttpClient;
use 
SomeEndpointHandler;

/**
 * Class SomeApiWrapper
 * 
 * @method SomeEndpointHandler method1(MethodParams $param1)
 * @method SomeEndpointHandler method2(MethodParams $param1, AuthParams $param2 = null)
 * ...
 * @method SomeEndpointHandler method42()
 */
class SomeApiWrapper{

   
/**
     * @var \SomeHttpClient
     */
   
private $httpClient;

   
/**
     * @var array
     */
   
private $methodMap = [];

   
/**
     * SomeApiWrapper constructor.
     */
   
public function __construct(){
       
$this->mapApiMethods();
       
$this->httpClient = new SomeHttpClient();
    }

   
/**
     * The API is flat and has ~ 150 endpoints, all of which take optional parameters
     * from up to 3 groups (method params, authentication, filters). Instead of
     * implementing the interface and adding countless stubs that have basically
     * the same signature, i just map its methods here and use __call().
     */
   
private function mapApiMethods(){
       
$reflectionClass = new ReflectionClass(SomeApiInterface::class);

        foreach(
$reflectionClass->getMethods() as $m){
           
$this->methodMap[] = $m->name;
        }
    }

   
/**
     * Thanks to the PHP 5.6+ "..." token, there's no hassle with the arguments anymore
     * (ugh, bad pun). Just hand the method parameters into the endpoint handler,
     * along with other mandatory params - type hints are your friends.
     * 
     * It's magic!
     * 
     * @param string $method
     * @param array  $arguments
     *
     * @return \SomeEndpointHandler
     * @throws \Exception
     */
   
public function __call($method$arguments){

        if(
in_array($method$this->methodMap)){
            return new 
SomeEndpointHandler($this->httpClient$method, ...$arguments);
        }

        throw new 
Exception('Endpoint "'.$method.'" does not exist');
    }

}
2016-01-09 06:30:05
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
__debugInfo  is also utilised when calling print_r on an object:

$ cat test.php
<?php
class FooQ {

     private 
$bar '';

     public function 
__construct($val) {

         
$this->bar $val;
     }

     public function 
__debugInfo()
     {
         return [
'_bar' => $this->bar];
     }
}
$fooq = new FooQ("q");
print_r ($fooq);

php test.php
FooQ Object
(
    [
_bar] => q
)
$
2017-05-30 16:27:10
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
http://sandbox.onlinephpfunctions.com/code/4d2cc3648aed58c0dad90c7868173a4775e5ba0c

IMHO a bug or need feature change

providing a object as a array index doesn't try to us __toString() method so some volatile object identifier is used to index the array, which is breaking any persistency. Type hinting solves that, but while other than "string" type hinting doesn't work on ob jects, the automatic conversion to string should be very intuitive.

PS: tried to submit bug, but withot patch the bugs are ignored, unfortunately, I don't C coding

<?php

class shop_product_id {
   
    protected 
$shop_name;
    protected 
$product_id;
   
    function 
__construct($shop_name,$product_id){
       
$this->shop_name $shop_name;
       
$this->product_id $product_id;
    }

    function 
__toString(){
        return 
$this->shop_name ':' $this->product_id;
    }
}

$shop_name 'Shop_A';
$product_id 123;
$demo_id $shop_name ':' $product_id;
$demo_name 'Some product in shop A';

$all_products = [ $demo_id => $demo_name ];
$pid = new shop_product_id$shop_name$product_id );

echo 
"with type hinting: ";
echo (
$demo_name === $all_products[(string)$pid]) ? "ok" "fail";
echo 
"\n";

echo 
"without type hinting: ";
echo (
$demo_name === $all_products[$pid]) ?  "ok" "fail";
echo 
"\n";
2018-04-30 12:29:39
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Due to a bug in PHP <= 7.3, overriding the __debugInfo() method from SPL classes is silently ignored.

<?php

class Debuggable extends ArrayObject {
  public function 
__debugInfo() {
    return [
'special' => 'This should show up'];
  }
}

var_dump(new Debuggable());

// Expected output:
// object(Debuggable)#1 (1) {
//   ["special"]=>
//   string(19) "This should show up"
// }

// Actual output:
// object(Debuggable)#1 (1) {
//   ["storage":"ArrayObject":private]=>
//   array(0) {
//   }
// }

?>

Bug report: https://bugs.php.net/bug.php?id=69264
2020-08-18 21:10:05
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
It should be noted that if you unset a class typed property and then try to access it,  __get will be called. But it MUST return the original type.

https://wiki.php.net/rfc/typed_properties_v2#overloaded_properties
2021-02-03 21:18:43
http://php5.kiev.ua/manual/ru/language.oop5.magic.html
Please note that as of PHP 8.2 implementing __serialize() has no control over the output of json_encode(). you still have to implement JsonSerializable.
2023-06-18 16:26:21
http://php5.kiev.ua/manual/ru/language.oop5.magic.html

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