--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpKernel\Config;
+
+use Symfony\Component\Config\Resource\SelfCheckingResourceInterface;
+
+/**
+ * EnvParametersResource represents resources stored in prefixed environment variables.
+ *
+ * @author Chris Wilkinson <chriswilkinson84@gmail.com>
+ */
+class EnvParametersResource implements SelfCheckingResourceInterface, \Serializable
+{
+ /**
+ * @var string
+ */
+ private $prefix;
+
+ /**
+ * @var string
+ */
+ private $variables;
+
+ /**
+ * Constructor.
+ *
+ * @param string $prefix
+ */
+ public function __construct($prefix)
+ {
+ $this->prefix = $prefix;
+ $this->variables = $this->findVariables();
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function __toString()
+ {
+ return serialize($this->getResource());
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getResource()
+ {
+ return array('prefix' => $this->prefix, 'variables' => $this->variables);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function isFresh($timestamp)
+ {
+ return $this->findVariables() === $this->variables;
+ }
+
+ public function serialize()
+ {
+ return serialize(array('prefix' => $this->prefix, 'variables' => $this->variables));
+ }
+
+ public function unserialize($serialized)
+ {
+ $unserialized = unserialize($serialized);
+
+ $this->prefix = $unserialized['prefix'];
+ $this->variables = $unserialized['variables'];
+ }
+
+ private function findVariables()
+ {
+ $variables = array();
+
+ foreach ($_SERVER as $key => $value) {
+ if (0 === strpos($key, $this->prefix)) {
+ $variables[$key] = $value;
+ }
+ }
+
+ ksort($variables);
+
+ return $variables;
+ }
+}