M2 Bootstrap Sample File

M2BootstrapSampleFile.php

<?php
/**
 *
 * M2 Bootstrap Sample File
 *
 */
ini_set('display_errors', 1);
error_reporting(E_ALL);

require __DIR__ . '/../app/bootstrap.php';

class TestApp extends \Magento\Framework\App\Http implements \Magento\Framework\AppInterface
{
    /**
     * Callback function
     *
     * @var \Closure
     */
    static $callback;

    /**
     * @var string
     */
    protected $areaCode = 'frontend';

    /**
     * Run M2 with $callback
     *
     * @param \Closure $callback
     * @return void
     */
    static public function run(\Closure $callback)
    {
        self::$callback = $callback;

        $bootstrap = \Magento\Framework\App\Bootstrap::create(BP, $_SERVER);
        $bootstrap->run($bootstrap->createApplication(__CLASS__));
    }

    /**
     * Launch
     *
     * @return
     */
    public function launch()
    {
        $objectManager = \Magento\Framework\App\ObjectManager::getInstance();

        $objectManager->get('\Magento\Framework\App\State')->setAreaCode($this->areaCode);

        $objectManager->configure(
            $objectManager->get('\Magento\Framework\ObjectManager\ConfigLoaderInterface')
                ->load($this->areaCode)
        );

        call_user_func(self::$callback, $objectManager);

        return $this->_response;
    }

    /**
     * Catch an exception
     *
     * @return
     */
    public function catchException(
        \Magento\Framework\App\Bootstrap $bootstrap,
        \Exception $exception
    ): bool
    {
        echo sprintf(
            '<h1>%s</h1><' . 'pre>%s<' . '/pre>', $exception->getMessage(), $exception->getTraceAsString()
        );

        exit;
    }
}

TestApp::run(function ($objectManager) {
    try {
        /**
         *          *
         * Custom code here
         *
         */

    } catch (\Exception $e) {
        echo $e->getMessage() . PHP_EOL . $e->getTraceAsString() . PHP_EOL . PHP_EOL;
    }
});