TYPO3 tutorial extension, controller does not exist - typo3

Question

I'm trying to get started with TYPO3 extensions and was following this tutorial to get to see the basics.
In the backend everything works fine, but on the front end I get an error:
Oops, an error occurred! Code: 20170209104827c3b58d58 -
{"exception":"exception 'ReflectionException' with message 'Class
Tx_Inventory_Controller_InventoryController does not exist'
My files are exactly the same as in the tutorial. I have no idea what is causing this. I assume I made some dumb mistake with namespaces, but they seem to be all correct.
The controller class can be found below and is located in typo3conf/ext/inventory/Classes/Controller/
<?php
namespace \MyVendor\Inventory\Controller;
use \TYPO3\CMS\Extbase\Mvc\Controller\ActionController;
use \TYPO3\CMS\Core\Utility\GeneralUtility;
use \MyVendor\Inventory\Domain\Model\Repository\ProductRepository;
class InventoryController extends ActionController {
public function listAction() {
$productRepository = GeneralUtility::makeInstance(ProductRepository::class)
$products = $productRepository->findAll();
$this->view->assign('products', $products);
}
}
?>

Answer 1

When developing a new extension in a composer installed TYPO3 V9 (here: 9.4) the autoload part has to be added to the central root composer.json. Found it here (German). Following the steps in the OPs mentioned tutorial leads to a core exception:
Core: Exception handler (WEB): Uncaught TYPO3 Exception: #1278450972:
Class MyVendor\StoreInventory\Controller\StoreInventoryController does not exist.
Reflection failed.
As long as the extension is not installed via composer, e.g because it's newly developed, composer does not find the appropriate composer.json file in the extensions directory. Hence TYPO3 does not find any classes in the new extensions Classes directory. To resolve the issue the autoload configuration has to be added to the root composer.json. Just put the following lines into composer.json within the installations base directory:
{
"repositories": [
{ "type": "composer", "url": "https://composer.typo3.org/" }
],
...
"autoload": {
"psr-4": {
"MyVendor\\StoreInventory\\": "public/typo3conf/ext/store_inventory/Classes/"
}
}
}
Then regenerate the autoload configuration:
composer dumpautoload
You possibly have to clear the cache as well in the backend.

Answer 2

It looks like your class is not autoloaded. If you don't use composer to make your autoload, take a look in your typo3conf/autoload/autoload_classmap.php file.
You should find an entry corresponding to your file. You will see if you have a path error.

Answer 3

Remove backslashes - try with
<?php
namespace MyVendor\Inventory\Controller;
use TYPO3\CMS\Extbase\Mvc\Controller\ActionController;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use MyVendor\Inventory\Domain\Model\Repository\ProductRepository;
class InventoryController extends ActionController {
public function listAction() {
$productRepository = GeneralUtility::makeInstance(ProductRepository::class)
$products = $productRepository->findAll();
$this->view->assign('products', $products);
}
}
Ensure you add Vendorname to extension key, when you register your plugin, see ext_tables.php and write 'MyVendor.'.$_EXTKEY instead of $_EXTKEY like
\TYPO3\CMS\Extbase\Utility\ExtensionUtility::registerPlugin(
'MyVendor.'.$_EXTKEY,
'List',
'The Inventory List'
);

Answer 4

I had exactly the same problem - it happens if Typo3 installation is done by composer. To solve this problem see this page of the docs.

Answer 5

Try to add autoload in your ext_emconf.php (replace 'Vendor\\Extensionkey\\') and uninstall and install your extension again (to rebuild PHP autoload information)
'autoload' =>
array (
'psr-4' =>
array (
'Vendor\\Extensionkey\\' => 'Classes',
),
),
'_md5_values_when_last_written' => 'a:0:{}',
'suggests' => array(
),