Fatal error due to composer.json in slim tree framework

Question

I have been following Alex Gareth's tutorial on building a shopping cart . I am stock because I think that the composer.json isn't autoloading my files correctly. Here is my error :

"Fatal error: Uncaught Error: Class 'Order\\App' not found in C:\\xampp\\htdocs\\order\\bootstrap\\app.php:10 Stack trace: #0 C:\\xampp\\htdocs\\order\\public\\index.php(3): require() #1 {main} thrown in C:\\xampp\\htdocs\\order\\bootstrap\\app.php on line 10"

composer.json file

    {
    "require": {
        "slim/slim": "^3.0",
        "slim/twig-view": "^2.4",
        "php-di/slim-bridge": "^2.0",
        "illuminate/database": "^5.6"
    },

    "autoload": {
        "psr-4": {
            "Order\\": "Order"
        }
    }
}

App class

    namespace Order;

    use DI\ContainerBuilder;
    use DI\Bridge\Slim\App as DIBridge;

    class App extends DIBridge{

        protected function configureContainer(ContainerBuilder $builder){
            $builder->addDefinitions([
                'settings.displayErrorDetails' => true
            ]);

            //
        }

}

app.php file which is the bootstrap file

<?php

use Order\App;

session_start();

require __DIR__ . '/../vendor/autoload.php';
//require __DIR__ . '/../app/App.php';

$app = new App;

If i un-comment the require line where i pulled in App.php it works fine.

Directory Structure:

OS : Windows 10

Answer 1

Try to change autoload to following:

"autoload": {
    "psr-4": {
        "Order\\": ""
    }
}

Answer 2

You should change your autoload to target the app/ folder instead, since there's where your App.php is located:

"autoload": {
    "psr-4": {
        "Order\\": "app/"
    }
}

What this essentially does is telling the autoloader that all classes that has the namespace Order\\ exists in app/ .

So from now on, if you would create sub folders in app/ :

app/
    App.php
    Foo/
        Bar.php

Then Bar.php should have the namespace Order\\Foo and you would access that class with: $bar = new Order\\Foo\\Bar() .

Note: This is where the file/folder casing is important. The namespace casing and the class name must have the same casing as the files and folders. Otherwise, it will still work for you on Windows, but it will fail on other OS's (like linux).