Autoload PSR4 class

Question

I would like to create a class of autoload to follow the recommendations of PSR4 which can be used jointly and independently of the autoload of the Composer.

The application I’m creating will have the following structure:

/root
 |--/src                
      |-- /App
            |-- /Config
            |-- /Controller
            |-- /Model
      |-- /Core
            |-- /Helper
            |-- /lib
                  |-- Autoload.class.php
  |-- /public_html
        |-- ...
  |-- /vendor  
        |-- ...
  |-- index.php      

In the future I will integrate new components in my application through Composer but, I would like an autoload class for the classes of my application.

Answer 1

Following the structure you used, simply create an event in a . php file that will be included within the index.php (which should go inside of public_html), note that the public_html will be your root (pro server), however this is not a must, I’m just following your folder structure.

For this you will have to use the spl_autoload_register, the link http://www.php-fig.org/psr/psr-4/examples/ - I made an example, with some modifications:

<?php
function myAutoLoader($class)
{
    // Diretório aonde ficam as bibliotecas
    $base_dir = __DIR__ . '/src/App/'; //A pasta que conterá os arquivos que serão autocarregados

    //Transforma namespace no caminho do arquivo
    $file = $base_dir . str_replace('\\', '/', $class) . '.php';

    // Verifica se o arquivo existe, se existir então inclui ele
    if (is_file($file)) {
        include_once $file;
    }
}

spl_autoload_register('myAutoLoader');

You can put it in (or use include) inside your index.php, or create a file within Core and use include calling him.

For more details, see this answer I made: What is spl_autoloader_register in PHP?

Notes on the code

• Note: Other than http://www.php-fig.org I used include_once instead of require, because if the file has already been manually included or it is not a class, it will present more errors than it should and the only error that the PSR-4 standard should present is that of undefined class.

• Note 2: I used is_file instead of file_existes, because although it is almost impossible yet a developer who use your project may end up creating a folder called ./src/App/Controller/foo.php/index.html, of course this is a user error, but as I said in the other note, PSR-4 shall only contain errors of undefined class (which is the standard) however if the require trying to call a folder will present an error as it file_exists returns true to directories:

  Warning: require(src/App/Controller/foo.php): failed to open stream: No such file or directory in Z: www project server.php on line 22

  Fatal error: require(): Failed Opening required 'src/App/Controller/foo.php' (include_path='.') in Z: www project server.php on line 22

The reason for this is because it is described here http://www.php-fig.org/psr/psr-4/#2-Specification:

Autoloader implementations MUST NOT release exceptions, must not generate errors of any level and must not return any value.