spl_autoload

(PHP 5 >= 5.1.2)

spl_autoload — Default implementation for __autoload()

Описание

void spl_autoload ( string $class_name [, string $file_extensions ] )

This function is intended to be used as a default implementation for __autoload(). If nothing else is specified and autoload_register() is called without any parameters then this functions will be used for any later call to __autoload().

Список параметров

class_name

file_extensions

By default it checks all include paths to contain filenames built up by the lowercase class name appended by the filename extensions .inc and .php.

Возвращаемые значения

Эта функция не возвращает значения после выполнения.

Коментарии

Note that, the orders of file extensions is important for performance. You should make the priority of your favourite file extension higest or use only one extension for your class files. Check out this example:

Some class files:

ClassA.php
<?php class ClassA { var $val 'Hello from class "ClassA"'; } ?>
ClassB.php
<?php class ClassB { var $val 'Hello from class "ClassB"'; } ?>
ClassC.php
<?php class ClassC { var $val 'Hello from class "ClassC"'; } ?>
ClassD.php
<?php class ClassD { var $val 'Hello from class "ClassD"'; } ?>
ClassE.php
<?php class ClassE { var $val 'Hello from class "ClassE"'; } ?>

1. Simple:
<?php
// default priority: .inc .php
for($n=65$n<70$n++) {
   
$className 'Class'.chr($n);
   
spl_autoload($className);
   
$ins = new $className;
    echo 
$ins->val.'<br>';
}
// 4.2 miliseconds
?>

2. Change priority:
<?php
spl_autoload_extensions
('.php,.inc');
// new priority: .php .inc
for($n=65$n<70$n++) {
   
$className 'Class'.chr($n);
   
spl_autoload($className);
   
$ins = new $className;
    echo 
$ins->val.'<br>';
}
// 1.4 miliseconds
?>

Or you can use this simple function that runs a bit faster for the extensions with lower priority :)
<?php
function my_autoload($className$extList='.inc,.php') {
   
$ext explode(',',$extList);
    foreach(
$ext as $x) {
       
$fname $className.$x;
        if(@
file_exists($fname)) {
            require_once(
$fname);
            return 
true;
        }
    }
    return 
false;
}

for(
$n=65$n<70$n++) {
   
$className 'Class'.chr($n);
   
my_autoload($className);
   
$ins = new $className;
    echo 
$ins->val.'<br>';
}
// 2.6 miliseconds
?>
---
Safak Ozpinar - Istanbul University, Computer Engineering
2007-09-25 22:17:25
http://php5.kiev.ua/manual/ru/function.spl-autoload.html
Note, that the default autoload implementation is written in C land and is always slightly faster then your native PHP one.

Here is a trick to use default implementation with any configuration:

<?php

   
// Your custom class dir
   
define('CLASS_DIR''class/')

   
// Add your class dir to include path
   
set_include_path(get_include_path().PATH_SEPARATOR.CLASS_DIR);

   
// You can use this trick to make autoloader look for commonly used "My.class.php" type filenames
   
spl_autoload_extensions('.class.php');

   
// Use default autoload implementation
   
spl_autoload_register();
?>

This also works with namespaces out of the box. So you can write code like "use My\Name\Object" and it will map to "class/My/Name/Object.class.php" file path!
2009-08-08 01:22:48
http://php5.kiev.ua/manual/ru/function.spl-autoload.html
Автор:
Note this function will LOWERCASE the class names its looking for, dont be confused when it cant find Foo_Bar.php

also, unlike most other autoloader code snippets, this function DOES NOT translate underscores to slashes.

class Foo_Bar {}
will load foo_bar.php and will not try to load foo/bar.php

You can get around this with
spl_autoload_register(function($class) { return spl_autoload(str_replace('_', '/', $class));});
2010-07-05 22:58:05
http://php5.kiev.ua/manual/ru/function.spl-autoload.html
Автор:
If you want to make the best use out of autoload with an APC cache don't use spl_autoload. It uses relative paths and thus will perform a stat even with apc.stat=0 (either that, or it doesn't work at all).

Instead make a custom function and use require/include with an absolute path (register it with spl_autoload_register).

Do NOT use *_once functions or a relative path. This will fail harder than spl_autoload.

Also avoid using file_exists and is_file. This will also perform a stat.

Why are stats bad? Because they access the file system. PHP does have a stat cache that helps, but it defeats the purpose of apc.stat = 0.

It's also good to keep in mind that it's good to keep your custom autoload function simple. This is my Loader class:

<?php

class Loader
{   
    public static function 
registerAutoload()
    {
        return 
spl_autoload_register(array(__CLASS__'includeClass'));
    }
   
    public static function 
unregisterAutoload()
    {
        return 
spl_autoload_unregister(array(__CLASS__'includeClass'));
    }
   
    public static function 
includeClass($class)
    {
        require(
PATH '/' strtr($class'_\\''//') . '.php');
    }
}

?>

Also want to point out that APC does an optimization with require/include (not *_once) with relative paths if require/include is done in the global scope (and isn't conditional). So it would be a good idea to explicitly include files you know you're going to use on every request (but don't use *_once). You could, for example, add a "registerProfiledAutoload" to the above class and keep track of what you're including to help you determine what you could explicitly include (during development, not production). The key is try not to make heavy use out of autoload.

If you must use relative paths and don't care about having to lower-case your file-names then spl_autoload works great.
2011-04-19 22:03:08
http://php5.kiev.ua/manual/ru/function.spl-autoload.html
Автор:
One small example that shows how you can use spl_autoload function in your MVC, Framewrk's applications. For example, will use the Loader class.
 

<?php

 
class Loader
 
{
       
   
/**
     * Controller Directory Path
     *
     * @var Array
     * @access protected
     */
   
protected $_controllerDirectoryPath = array();
   
   
/**
     * Model Directory Path
     *
     * @var Array
     * @access protected
     */
   
protected $_modelDirectoryPath = array();
   
   
/**
     * Library Directory Path
     *
     * @var Array
     * @access protected
     */
   
protected $_libraryDirectoryPath = array();
   
   
   
/** 
     * Constructor
     * Constant contain my full path to Model, View, Controllers and Lobrary-
     * Direcories.
     *
     * @Constant MPATH,VPATH,CPATH,LPATH
     */
     
   
public function __construct()
    {
       
$this->modelDirectoryPath      MPATH;
       
$this->viewDirectoryPath        VPATH;
       
$this->controllerDirectoryPath CPATH;
       
$this->libraryDirectoryPath     LPATH;
       
       
spl_autoload_register(array($this,'load_controller'));
       
spl_autoload_register(array($this,'load_model'));
       
spl_autoload_register(array($this,'load_library'));
   
       
log_message('debug',"Loader Class Initialized");
    }

   
/** 
     *-----------------------------------------------------
     * Load Library
     *-----------------------------------------------------
     * Method for load library.
     * This method return class object.
     *
     * @library String
     * @param String
     * @access public
     */   
   
public function load_library($library$param null)
    {
        if (
is_string($library)) {
            return 
$this->initialize_class($library);
        }
        if (
is_array($library)) {
            foreach (
$library as $key) {
                return 
$this->initialize_class($library);
            }
        }               
    }

   
/** 
     *-----------------------------------------------------
     * Initialize Class
     *-----------------------------------------------------
     * Method for initialise class
     * This method return new object. 
     * This method can initialize more class using (array)
     *
     * @library String|Array
     * @param String
     * @access public
     */   
   
public function initialize_class($library)
    {
        try {
            if (
is_array($library)) {
                foreach(
$library as $class) {
                   
$arrayObject =  new $class;
                }           
                return 
$this;
            }
            if (
is_string($library)) {
               
$stringObject = new $library;
            }else {
                throw new 
ISException('Class name must be string.');
            }
            if (
null == $library) {
                throw new 
ISException('You must enter the name of the class.');
            }
        } catch(
Exception $exception) {
            echo 
$exception;
        }
    }   
   
   
/**
     * Autoload Controller class
     *
     * @param  string $class
     * @return object
     */
     
   
public function load_controller($controller)
    {
        if (
$controller) {
           
set_include_path($this->controllerDirectoryPath);
           
spl_autoload_extensions('.php');
           
spl_autoload($class);
        }
    }   
   

     
/**
     * Autoload Model class
     *
     * @param  string $class
     * @return object
     */
     
   
public function load_models($model)
    {
        if (
$model) {
           
set_include_path($this->modelDirectoryPath);
           
spl_autoload_extensions('.php');
           
spl_autoload($class);
        }
    }   
   
     
/**
     * Autoload Library class
     *
     * @param  string $class
     * @return object
     */
     
   
public function load_library($library)
    {
        if (
$library) {
           
set_include_path($this->libraryDirectoryPath);
           
spl_autoload_extensions('.php');
           
spl_autoload($class);
        }
    }
   

   
 }
 
 
?>
2012-06-06 16:19:28
http://php5.kiev.ua/manual/ru/function.spl-autoload.html
<?php
/*
* defined function responsible for loading class,
* replacing the old __ autoload.
* ROOT is constant of the path root of the system
*/
spl_autoload_extensions('.class.php');
spl_autoload_register('loadClasses');

 function 
loadClasses($className)
 {
   
    if( 
file_exists(ROOT_DIR.DS.'controller/'.$className.'.class.php' ) ){
       
set_include_path(ROOT_DIR.DS.'controller'.DS);
       
spl_autoload($className);
    }
    elseif( 
file_exists('model/'.$className.'.class.php' ) ){
       
set_include_path(ROOT_DIR.DS.'model'.DS);
       
spl_autoload($className);
    }elseif( 
file_exists('view/'.$className.'.class.php' ) ){
       
set_include_path(ROOT_DIR.DS.'view'.DS);
       
spl_autoload($className    );
    }else
    {
       
set_include_path(ROOT_DIR.DS.'lib'.DS);
       
spl_autoload($className    );
    }
 }
?>
2012-09-24 00:14:37
http://php5.kiev.ua/manual/ru/function.spl-autoload.html
Автор:
The documentation is a little unclear when it says: "The lowercased name of the class (and namespace) being instantiated". 

What it actually means is that the argument can be in whatever case you want, but it will be converted to lowercase before PHP starts looking for files. This is probably because in PHP, class names are case-insensitive (as well as function names and namespaces) so it needs to convert to some canonical format.
2013-11-05 17:05:38
http://php5.kiev.ua/manual/ru/function.spl-autoload.html
Автор:
Just thought I'd react to simast at gmail dot com's note: While he has a point in saying C outperforms PHP, his suggestion is micro-optimization. I'm not 100% against micro-optimizing code, but if you do, go all the way:

<?php

   
// Your custom class dir
   
define('CLASS_DIR''class/')

   
// Add your class dir to include path
   
set_include_path(get_include_path().PATH_SEPARATOR.CLASS_DIR);

This adds the include path to THE END of the paths PHP will scan for the class fileresulting in a bunch of misses (file-not-found's) before actually looking into the CLASS_DIR.
A more sensible approach, then would be to write

    set_include_path(
        CLASS_DIR.
        PATH_SEPARATOR,
        get_include_path()
    );
2014-04-15 11:39:46
http://php5.kiev.ua/manual/ru/function.spl-autoload.html
Both namespaces and class names are case insensitive. This can cause problems with autoloading in OS/filesystems that _are_

Consider this code:
<?php declare(strict_types=1);
set_include_path(get_include_path() . PATH_SEPARATOR 'class/');
spl_autoload_extensions('.class.php');
spl_autoload_register();

$foobar = new \foo\bar();
?>

and a class file /class/foo/bar.class.php:
<?php declare(strict_types=1);
namespace 
Foo;

class 
Bar {
  public function 
__construct() {
    echo 
'Map constructed';
  }
}
?>

this will work fine regardless of a case sensitive or not case sensitive OS/FS. 

A file called ./class/Foo/Bar.class.php will only be found on a not case sensitive situation as the default class loader will mb_strtolower() the class name to find the class filename.

Btw. this content of a class file will be equivalent to the one above:
<?php declare(strict_types=1);
namespace 
foo;

class 
bar {
  public function 
__construct() {
    echo 
'Map constructed';
  }
}
?>

The class /foo/bar and /Foo/Bar are one and the same thing.
2022-07-09 13:41:07
http://php5.kiev.ua/manual/ru/function.spl-autoload.html

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