Autoload classes from different folders

I see you are using controller_***** and model_***** as a class naming convention.

I read a fantastic article, which suggests an alternative naming convention using php's namespace.

I love this solution because it doesn't matter where I put my classes. The __autoload will find it no matter where it is in my file structure. It also allows me to call my classes whatever I want. I don't need a class naming convention for my code to work.

You can, for example, set up your folder structure like:

application/
1. controllers/
  - Base.php
  - Factory.php
2. models/
  - Page.php
  - Parent.php

Your classes can be set up like this:

<?php
namespace application\controllers;
class Base {...}

and:

<?php
namespace application\models;
class Page {...}

The autoloader could look like this (or see 'a note on autoloading' at the end):

function __autoload($className) {
    $file = $className . '.php';
    if(file_exists($file)) {
        require_once $file;
    }
}

Then... you can call classes in three ways:

$controller = new application\controllers\Base();
$model = new application\models\Page();

or,

<?php
use application\controllers as Controller;
use application\models as Model;

...

$controller = new Controller\Base();
$model = new Model\Page();

or,

<?php
use application\controllers\Base;
use application\models\Page;

...

$controller = new Base();
$model = new Page();

EDIT - a note on autoloading:

My main auto loader looks like this:

// autoload classes based on a 1:1 mapping from namespace to directory structure.
spl_autoload_register(function ($className) {

    # Usually I would just concatenate directly to $file variable below
    # this is just for easy viewing on Stack Overflow)
        $ds = DIRECTORY_SEPARATOR;
        $dir = __DIR__;

    // replace namespace separator with directory separator (prolly not required)
        $className = str_replace('\\', $ds, $className);

    // get full name of file containing the required class
        $file = "{$dir}{$ds}{$className}.php";

    // get file if it is readable
        if (is_readable($file)) require_once $file;
});

This autoloader is a direct 1:1 mapping of class name to directory structure; the namespace is the directory path and the class name is the file name. So the class application\controllers\Base() defined above would load the file www/application/controllers/Base.php.

I put the autoloader into a file, bootstrap.php, which is in my root directory. This can either be included directly, or php.ini can be modified to auto_prepend_file so that it is included automatically on every request.

By using spl_autoload_register you can register multiple autoload functions to load the class files any which way you want. Ie, you could put some or all of your classes in one directory, or you could put some or all of your namespaced classes in the one file. Very flexible :)

You should name your classes so the underscore (_) translates to the directory separator (/). A few PHP frameworks do this, such as Zend and Kohana.

So, you name your class Model_Article and place the file in classes/model/article.php and then your autoload does...

function __autoload($class_name) 
{
    $filename = str_replace('_', DIRECTORY_SEPARATOR, strtolower($class_name)).'.php';

    $file = AP_SITE.$filename;

    if ( ! file_exists($file))
    {
        return FALSE;
    }
    include $file;
}

Also note you can use spl_autoload_register() to make any function an autoloading function. It is also more flexible, allowing you to define multiple autoload type functions.

If there must be multiple autoload functions, spl_autoload_register() allows for this. It effectively creates a queue of autoload functions, and runs through each of them in the order they are defined. By contrast, __autoload() may only be defined once.

Edit

Note : __autoload has been DEPRECATED as of PHP 7.2.0. Relying on this feature is highly discouraged. Please refer to PHP documentation for more details. http://php.net/manual/en/function.autoload.php

I have to mention something about "good" autoload scripts and code structure, so read the following CAREFULLY

Keep in Mind:

Classname === Filename
Only ONE class per file

e.g: Example.php contains

class Example {}

Namespace === Directory structure

e.g: /Path1/Path2/Example.php matches

namespace Path1\Path2;
class Example {}

There SHOULD be a Root-Namespace to avoid collisions

e.g: /Path1/Path2/Example.php with root:

namespace APP\Path1\Path2;
class Example {}

NEVER use manually defined path or directory lists, just point the loader to the top most directory
Keep the loader AS FAST AS POSSIBLE (because including a file is expensive enough)

With this in mind, i produced the following script:

function Loader( $Class ) {
    // Cut Root-Namespace
    $Class = str_replace( __NAMESPACE__.'\\', '', $Class );
    // Correct DIRECTORY_SEPARATOR
    $Class = str_replace( array( '\\', '/' ), DIRECTORY_SEPARATOR, __DIR__.DIRECTORY_SEPARATOR.$Class.'.php' );
    // Get file real path
    if( false === ( $Class = realpath( $Class ) ) ) {
        // File not found
        return false;
    } else {
        require_once( $Class );
        return true;
    }
}

Where to place it..

/Loader.php <-- there goes the loader
/Controller/... <-- put ur stuff here
/Model/... <-- or here, etc
/...

Remeber:

if you use a root namespace, the loader has to be in this namespace too
you may prefix $Class to match your needs (controller_base {} -> class_controller_base.php)
you may change __DIR__ to an absolute path containing your class files (e.g. "/var/www/classes")
if you don't use namespaces, all files has to be in the same directory together with the loader (bad!)

Happy coding ;-)

A little review at other answers: THIS IS JUST MY PERSONAL OPINION - NO OFFENSE INTENDED!

https://stackoverflow.com/a/5280353/626731 @alex good solution, but don't make you class names pay for bad file structures ;-) this is job for namespaces

https://stackoverflow.com/a/5280510/626731 @Mark-Eirich it works, but its pretty nasty/ugly/slow/stiff[..] style to do it this way..

https://stackoverflow.com/a/5284095/626731 @tealou for his problem to be solved this is the most clear approach so far :-) ..

https://stackoverflow.com/a/9628060/626731 @br3nt this reflects my point of view, but please(!) .. dont use strtr!! .. which brings me to:

https://stackoverflow.com/a/11866307/626731 @Iscariot .. to you, a little "you-know-bullshit-benchmark:

Time        sprintf preg_replace strtr    str_replace v1 str_replace v2
08:00:00 AM 1.1334  2.0955       48.1423  1.2109         1.4819
08:40:00 AM 1.0436  2.0326       64.3492  1.7948         2.2337
11:30:00 AM 1.1841  2.5524       62.0114  1.5931         1.9200
02:00:00 PM 0.9783  2.4832       52.6339  1.3966         1.4845
03:00:00 PM 1.0463  2.6164       52.7829  1.1828         1.4981
Average     1.0771  2.3560       55.9839  1.4357         1.7237


Method         Times Slower (than sprintf)
preg_replace   2.19
strtr          51.97
str_replace v1 1.33
str_replace v2 1.6

Source: http://www.simplemachines.org/community/index.php?topic=175031.0

Questions?.. (But he is in fact right about full path including)

https://stackoverflow.com/a/12548558/626731 @Sunil-Kartikey https://stackoverflow.com/a/17286804/626731 @jurrien

NEVER loop in time critical environment! Don't search for files on os! - SLOW

https://stackoverflow.com/a/21221590/626731 @sagits .. much better than Marks ;-)

function autoload($className)
{
//list comma separated directory name
$directory = array('', 'classes/', 'model/', 'controller/');

//list of comma separated file format
$fileFormat = array('%s.php', '%s.class.php');

foreach ($directory as $current_dir)
{
    foreach ($fileFormat as $current_format)
    {

        $path = $current_dir.sprintf($current_format, $className);
        if (file_exists($path))
        {
            include $path;
            return ;
        }
    }
}
}
spl_autoload_register('autoload');

Here is my solution,

/**
     * autoload classes 
     *
     *@var $directory_name
     *
     *@param string $directory_name
     *
     *@func __construct
     *@func autoload
     *
     *@return string
    */
    class autoloader
    {
        private $directory_name;

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

        public function autoload($class_name) 
        { 
            $file_name = 'class_'.strtolower($class_name).'.php';

            $file = AP_SITE.$this->directory_name.'/'.$file_name;

            if (file_exists($file) == false)
            {
                return false;
            }
            include ($file);
        }
    }

    # nullify any existing autoloads
    spl_autoload_register(null, false);

    # instantiate the autoloader object
    $classes_1 = new autoloader('controllers');
    $classes_2 = new autoloader('models');

    # register the loader functions
    spl_autoload_register(array($classes_1, 'autoload'));
    spl_autoload_register(array($classes_2, 'autoload'));

I'm not sure whether it is the best solution or not but it seems to work perfectly...

What do you think??

Autoload classes from different folders

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