<?php
declare(strict_types=1);
namespace Dotenv\Loader;
use Dotenv\Parser\Value;
use Dotenv\Repository\RepositoryInterface;
use Dotenv\Util\Regex;
use Dotenv\Util\Str;
use PhpOption\Option;
final class Resolver
{
/**
* This class is a singleton.
*
* @codeCoverageIgnore
*
* @return void
*/
private function __construct()
{
//
}
/**
* Resolve the nested variables in the given value.
*
* Replaces ${varname} patterns in the allowed positions in the variable
* value by an existing environment variable.
*
* @param \Dotenv\Repository\RepositoryInterface $repository
* @param \Dotenv\Parser\Value $value
*
* @return string
*/
public static function resolve(RepositoryInterface $repository, Value $value)
{
return \array_reduce($value->getVars(), static function (string $s, int $i) use ($repository) {
return Str::substr($s, 0, $i).self::resolveVariable($repository, Str::substr($s, $i));
}, $value->getChars());
}
/**
* Resolve a single nested variable.
*
* @param \Dotenv\Repository\RepositoryInterface $repository
* @param string $str
*
* @return string
*/
private static function resolveVariable(RepositoryInterface $repository, string $str)
{
return Regex::replaceCallback(
'/\A\${([a-zA-Z0-9_.]+)}/',
static function (array $matches) use ($repository) {
return Option::fromValue($repository->get($matches[1]))
->getOrElse($matches[0]);
},
$str,
1
)->success()->getOrElse($str);
}
}