Rename examples and update some comments.

[ci skip]

examples/session_handler.php

@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+require __DIR__.'/shared.php';
+
+// This example demonstrates how to use Predis to save PHP sessions on Redis.
+//
+// The value of `session.gc_maxlifetime` in `php.ini` will be used by default as
+// the TTL for keys holding session data but this value can be overridden when
+// creating the session handler instance using the `gc_maxlifetime` option.
+//
+// NOTE: this class requires PHP >= 5.4 but can be used on PHP 5.3 if a polyfill
+// for SessionHandlerInterface is provided either by you or an external package
+// like `symfony/http-foundation`.
+//
+// See http://www.php.net/class.sessionhandlerinterface.php for more details.
+//
+
+if (!interface_exists('SessionHandlerInterface')) {
+    die("ATTENTION: the session handler implemented by Predis requires PHP >= 5.4.0 ".
+        "or a polyfill for SessionHandlerInterface provided by an external package.\n");
+}
+
+// Instantiate a new client just like you would normally do. Using a prefix for
+// keys will effectively prefix all session keys with the specified string.
+$client = new Predis\Client($single_server, array('prefix' => 'sessions:'));
+
+// Set `gc_maxlifetime` to specify a time-to-live of 5 seconds for session keys.
+$handler = new Predis\Session\Handler($client, array('gc_maxlifetime' => 5));
+
+// Register the session handler.
+$handler->register();
+
+// We just set a fixed session ID only for the sake of our example.
+session_id('example_session_id');
+
+session_start();
+
+if (isset($_SESSION['foo'])) {
+    echo "Session has `foo` set to {$_SESSION['foo']}", PHP_EOL;
+} else {
+    $_SESSION['foo'] = $value = mt_rand();
+    echo "Empty session, `foo` has been set with $value", PHP_EOL;
+}