在php中 为什么不能使用redis类

在Mac OS上安装redis
首先是安装，它会默认安装到/usr/local/bin下

代码如下:

cd /tmp
wget
tar -zxf redis-2.6.9.tar.gz
cd redis-2.6.9
make
sudo make install

private function __construct($config,$attr=array())
{
$this->attr = array_merge($this->attr,$attr);
$this->redis = new Redis();
$this->port = $config['port'] ? $config['port'] : 6379;
$this->host = $config['host'];
$this->redis->connect($this->host, $this->port, $this->attr['timeout']);

if($config['auth'])
{
$this->auth($config['auth']);
$this->auth = $config['auth'];
}

$this->expireTime = time() + $this->attr['timeout'];
}