ext_localconf.php

<?php

if (!defined('TYPO3')) {
    die('Access denied.');
}

// register driver, see https://typo3.slack.com/archives/C03AM9R17/p1538658116000100
$GLOBALS['TYPO3_CONF_VARS']['SYS']['fal']['registeredDrivers'][\B3N\AzureStorage\TYPO3\Driver\StorageDriver::class] = [
    'class' => \B3N\AzureStorage\TYPO3\Driver\StorageDriver::class,
    'shortName' => \B3N\AzureStorage\TYPO3\Driver\StorageDriver::class,
    'label' => 'Azure Storage',
    'flexFormDS' => 'FILE:EXT:azurestorage/Configuration/FlexForms/AzureStorage.xml'
];

// Cache configuration, see http://wiki.typo3.org/Caching_Framework
if (!isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['azurestorage'])
    || !is_array($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['azurestorage'])) {
    $GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['azurestorage'] = array(
        'backend' => 'TYPO3\CMS\Core\Cache\Backend\Typo3DatabaseBackend',
        'options' => [
            'defaultLifetime' => \TYPO3\CMS\Core\Cache\Backend\Typo3DatabaseBackend::UNLIMITED_LIFETIME
        ],
    );
}
$extractorRegistry = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Core\Resource\Index\ExtractorRegistry::class);
$extractorRegistry->registerExtractionService(\B3N\AzureStorage\TYPO3\Index\Extractor::class);

/* @var $signalSlotDispatcher \TYPO3\CMS\Extbase\SignalSlot\Dispatcher */
$signalSlotDispatcher = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Extbase\SignalSlot\Dispatcher::class);
$signalSlotDispatcher->connect(\TYPO3\CMS\Core\Resource\Index\FileIndexRepository::class, 'recordUpdated', \B3N\AzureStorage\TYPO3\Signal\FileIndexRepository::class, 'recordUpdatedOrCreated');
$signalSlotDispatcher->connect(\TYPO3\CMS\Core\Resource\Index\FileIndexRepository::class, 'recordCreated', \B3N\AzureStorage\TYPO3\Signal\FileIndexRepository::class, 'recordUpdatedOrCreated');