FileValidatorSettingsTrait.php

<?php

namespace Drupal\file\Validation;

use Drupal\Component\Utility\Bytes;
use Drupal\Component\Utility\Environment;

/**
 * Provides a trait to create validators from settings.
 */
trait FileValidatorSettingsTrait {
    
    /**
     * Gets the upload validators for the specified settings.
     *
     * @param array $settings
     *   An associative array of settings. The following keys are supported:
     *     - max_filesize: The maximum file size in bytes. Defaults to the PHP max
     *     upload size.
     *     - file_extensions: A space-separated list of allowed file extensions.
     *
     * @return array
     *   An array suitable for passing to file_save_upload() or the file field
     *   element's '#upload_validators' property.
     */
    public function getFileUploadValidators(array $settings) : array {
        $validators = [
            // Add in our check of the file name length.
'FileNameLength' => [],
        ];
        // Cap the upload size according to the PHP limit.
        $maxFilesize = Bytes::toNumber(Environment::getUploadMaxSize());
        if (!empty($settings['max_filesize'])) {
            $maxFilesize = min($maxFilesize, Bytes::toNumber($settings['max_filesize']));
        }
        // There is always a file size limit due to the PHP server limit.
        $validators['FileSizeLimit'] = [
            'fileLimit' => $maxFilesize,
        ];
        // Add the extension check if necessary.
        if (!empty($settings['file_extensions'])) {
            $validators['FileExtension'] = [
                'extensions' => $settings['file_extensions'],
            ];
        }
        return $validators;
    }

}