Add memchached implementation for token cache

lib/OpenPayU/Oauth/Cache/OauthCacheMemcached.php

@@ -0,0 +1,43 @@
+<?php
+
+class OauthCacheMemcached implements OauthCacheInterface
+{
+    private $memcached;
+
+    /**
+     * @param string $host
+     * @param int $port
+     * @param int $weight
+     * @throws OpenPayU_Exception_Configuration
+     */
+    public function __construct($host = 'localhost', $port = 11211, $weight = 0)
+    {
+        if (!class_exists('Memcached')) {
+            throw new OpenPayU_Exception_Configuration('PHP Memcached extension not installed.');
+        }
+
+        $this->memcached = new Memcached('PayU');
+        $this->memcached->addServer($host, $port, $weight);
+        $stats = $this->memcached->getStats();
+        if ($stats[$host . ':' . $port]['pid'] == -1) {
+            throw new OpenPayU_Exception_Configuration('Problem with connection to memcached server [host=' . $host . '] [port=' . $port . '] [weight=' . $weight . ']');
+        }
+    }
+
+    public function get($key)
+    {
+        $cache = $this->memcached->get($key);
+        return $cache === false ? null : unserialize($cache);
+    }
+
+    public function set($key, $value)
+    {
+        return $this->memcached->set($key, serialize($value));
+    }
+
+    public function invalidate($key)
+    {
+        return $this->memcached->delete($key);
+    }
+
+}

lib/openpayu.php

@@ -25,6 +25,7 @@
 require_once('OpenPayU/Oauth/OauthResultClientCredentials.php');
 require_once('OpenPayU/Oauth/Cache/OauthCacheInterface.php');
 require_once('OpenPayU/Oauth/Cache/OauthCacheFile.php');
+require_once('OpenPayU/Oauth/Cache/OauthCacheMemcached.php');
 
 require_once('OpenPayU/ResultError.php');