php oop - each class different file? import package? etc

Question

I am used to working in languages such as C#/Java/Python where each class would have its own file, and for a class to see other classes, you would import the package containing those classes. How does this work in php? The documentation shows you how to create classes, but I don't understand how it all fits together in a php context. I know of the include statement, which just sticks the files together basically.

possible duplicate of [Import package or autoloading for PHP?](http://stackoverflow.com/questions/616231/import-package-or-autoloading-for-php) — Gordon, Jan 21 '11 at 11:05
Personally, I find it very sensible to have each class in its own file... but use an autoloader rather than java's import — Mark Baker, Jan 21 '11 at 11:07
@middaparka: I was the subject of a completely off-topic (although short-lived) discussion just the other day. — BoltClock, Jan 21 '11 at 11:18
@middaparka: The comment that started it was removed by flagging, but contextual remnants can be found in meagar's reply [here](http://stackoverflow.com/questions/4717369/conditional-loop). — BoltClock, Jan 21 '11 at 11:49
Check out psr-4 autoloading using Composer - https://getcomposer.org/ . It will greatly help with organization, especially in the realm of namespacing. — Douglas.Sesar, Mar 11 '15 at 11:34

Ákos Nikházy · Accepted Answer · 2015-12-02T08:16:42.110

16

You can use __autoload

function __autoload($class_name) {
    include 'classes/'.$class_name . '.php';
}

So place every single class in its own file in the classes folder. When you want to use that class it will include it. More info: http://php.net/manual/en/language.oop5.autoload.php

Update: When I answered this it was fully valid. Now it still works, but keep in mind PHP.net since then says this:

spl_autoload_register() provides a more flexible alternative for autoloading classes. For this reason, using __autoload() is discouraged and may be deprecated or removed in the future.

edited Dec 02 '15 at 08:16

answered Jan 21 '11 at 11:14

Ákos Nikházy

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2

Also take a look at: http://www.php.net/manual/en/function.spl-autoload-register.php – Mchl Jan 21 '11 at 11:22

Kamil Tomšík · Answer 2 · 2011-02-05T11:16:08.210

5

The easiest way:

define your classes in "classes" directory
init application like shown below
name class filenames as their lowercase class name with .php suffix (MyClass => classes/myclass.php)

Init code:

set_include_path ( "./classes" );
spl_autoload_register ();

//class is automatically loaded from ./classes/myclass.php
$object_instance = new MyClass ();

edited Feb 05 '11 at 11:16

answered Jan 21 '11 at 13:04

Kamil Tomšík

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score 3 · Answer 3 · answered Aug 27 '12 at 20:29

As of PHP 5.3.0 , it is recommended that you use the spl_autoload_register() function because __autoload() is said to be deprecated some time in the future.

An easy way to use this function:

1) Place each class file into the 'classes' folder

2) Run an anonymous function inside spl_autoload_register() which specifies your class folder:

spl_autoload_register(function ($class) {
    include 'classes/' . $class . '.php';
});

Now when you try to use a class that is not defined in your code yet, it will check that class folder one last time before giving you an error.

This is cool but this is best used when you want your own autoloader with its own name as described in Example #1 here: http://php.net/manual/en/function.spl-autoload-register.php In this case __autoload is enough. — Ákos Nikházy, Mar 11 '15 at 11:39

score 1 · Answer 4 · answered Jan 21 '11 at 11:08

1

Imagine you have been making your object in PHP in a file called myObject.php

<?php

  class myObject
  {
    public function __construct()
    {
      echo "Hello, World";
    }
  }

?>

And in another file, you would like to use the object (let's call this myfile.php). You would have to include your object - like this:

<?php

  include("myObject.php");

  $intance = new myObject();

?>

Quite simple.

answered Jan 21 '11 at 11:08

Repox

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Until you need to manage a list of includes that's longer than your code. – Mchl Jan 21 '11 at 11:09
@Mchl: Oh that's easy, place the includes in their own include file and include it :P – BoltClock Jan 21 '11 at 11:19

score 0 · Answer 5 · answered Jan 21 '11 at 11:08

0

In PHP you can do it in various ways, compiler does not limit you.

You can have 1 class in 1 file, 5 classes in 1 file, 1 class across several files using includes...

But usually it's still 1 class in 1 files, and if you have many tiny ones - you can have them in 1 folder too.

When doing 1 class in 1 file with the same name you can set up class autoload so that you don't need to write your includes.

answered Jan 21 '11 at 11:08

BarsMonster

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You can NOT have a class split over multiple files. See here for example: http://stackoverflow.com/questions/1957732/can-i-include-code-into-a-php-class/1957830#1957830 – yokmp Aug 03 '15 at 18:20

php oop - each class different file? import package? etc

5 Answers5