nextcloud/apps/files/ajax/delete.php

<?php

// Init owncloud


OCP\JSON::checkLoggedIn();
OCP\JSON::callCheck();

// Get data
$dir = stripslashes($_POST["dir"]);
$files = isset($_POST["file"]) ? stripslashes($_POST["file"]) : stripslashes($_POST["files"]);

$files = explode(';', $files);
$filesWithError = '';
if (OC_User::isLoggedIn()) {
	$success = true;

	//Now delete
	foreach ($files as $file) {
		if ($dir != '' || $file != 'Shared' && !\OC\Files\Filesystem::unlink($dir . '/' . $file)) {
			$filesWithError .= $file . "\n";
			$success = false;
		}
	}
} else {
	$success = false;
}

if ($success) {
	OCP\JSON::success(array("data" => array("dir" => $dir, "files" => $files)));
} else {
	OCP\JSON::error(array("data" => array("message" => "Could not delete:\n" . $filesWithError)));
}