ubuntu: create a simple php autoloader with composer

Here is a simple example how to setup a simple autoloader with composer classmap.

1) install composer:
http://magento2-tuts.blogspot.de/2016/08/ubuntu-install-composer.html

2) create 2 classes in 2 folders.
- create a folder named "myproject"
- in this folder create a folder "app" and a folder "library"
- so that you have this structure:
--myproject
  |__app
  |__library
      |__Calculator.php

In the app/library folder create a php Class "Calculator.php"

	<?php
	/**
	* Created by PhpStorm.
	* User: root
	* Date: 04.08.16
	* Time: 08:31
	*/
	class Calculator
	{
	public function add($summant1, $summant2)
	{
	return $summant1 + $summant2;
	}
	}

view raw Calculator hosted with ❤ by GitHub

create autoloader
- in the "myproject" folder create a file "composer.json" with follwing content

	{
	"autoload":
	{
	"classmap":[
	"app/library"
	]
	}
	}

view raw composer.json hosted with ❤ by GitHub

Switch to your terminal to the folder, where your composer.json is stored. type:
php composer install

After that a "vendor" folder is generated with the autoloading files.
Every Classes which are stored in the classmap ("app/library") will be automaticly added to the autoloading classmap.


Create a file "index.php" in folder "myproject" and add folling content,:

	<?php
	/**
	* Created by PhpStorm.
	* User: root
	* Date: 04.08.16
	* Time: 09:55
	*/
	require "vendor/autoload.php";
	$calculator = new Calculator();
	echo PHP_EOL.$calculator->add(2,2).PHP_EOL;

view raw index.php hosted with ❤ by GitHub

You now can use the calculator class without require or include like that:

Switch to terminal and type:
php index.php

this will output the result of 2+2 in yout terminal. You see the class Calculator gets automaticly loaded.


Now lets add a new folder "models" to the classmap
- create a folder named "models" in the folder "myproject"
- create a php class "User.php" in that folder

	<?php
	/**
	* Created by PhpStorm.
	* User: root
	* Date: 04.08.16
	* Time: 09:08
	*/
	class User
	{
	}

view raw User.pho hosted with ❤ by GitHub

Now add the new folder "models" to the composer.json classmap
- open composer.json and add "app/models" to the classmap, so that it looks like that:

	{
	"autoload":
	{
	"classmap":
	[
	"app/library",
	"app/models"
	]
	}
	}

view raw gistfile1.txt hosted with ❤ by GitHub

- switch back to your terminal in the folder where composer.json is stored and type:
php composer dump-autoload


If you open vendor/autoload_classmap.php you will see the new addition of the Usermodel.


Thats it.

In one of the next tutorials, PSR 0 and PSR 4 will be explained.