Add example for master / slave replication.

examples/MasterSlaveReplication.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 'SharedConfigurations.php';
+
+// Predis supports master / slave replication scenarios where write operations are
+// performed on the master server and read operations are executed against one of
+// the slaves. The behaviour of commands or EVAL scripts can be customized at will.
+// As soon as a write operation is performed, all the subsequent requests (reads
+// or writes) will be served by the master server.
+//
+// This example must be executed with the second Redis server acting as the slave
+// of the first one using the SLAVEOF command.
+//
+
+$parameters = array(
+    'tcp://127.0.0.1:6379?database=15&alias=master',
+    'tcp://127.0.0.1:6379?database=15&alias=slave',
+);
+
+$options = array('replication' => true);
+
+$client = new Predis\Client($parameters, $options);
+
+// Read operation.
+$exists = $client->exists('foo') ? 'yes' : 'no';
+$current = $client->getConnection()->getCurrent()->getParameters();
+echo "Does 'foo' exist on {$current->alias}? $exists.\n";
+
+// Write operation.
+$client->set('foo', 'bar');
+$current = $client->getConnection()->getCurrent()->getParameters();
+echo "Now 'foo' has been set to 'bar' on {$current->alias}!\n";
+
+// Read operation.
+$bar = $client->get('foo');
+$current = $client->getConnection()->getCurrent()->getParameters();
+echo "We just fetched 'foo' from {$current->alias} and its value is '$bar'.\n";
+
+/* OUTPUT:
+Does 'foo' exist on slave? yes.
+Now 'foo' has been set to 'bar' on master!
+We just fetched 'foo' from master and its value is 'bar'.
+*/