redis 锁

/**
 *  Redis锁操作类
 *  Date:   2016-06-30
 *  Author: fdipzone
 *  Ver:    1.0
 *
 *  Func:
 *  public  lock    获取锁
 *  public  unlock  释放锁
 *  private connect 连接
 */
class RedisLock
{
    // class start

    private $_config;
    private $_redis;

    /**
     * 初始化
     * @param Array $config redis连接设定
     */
    public function __construct($config = array())
    {
        $this->_config = $config;
        $this->_redis  = $this->connect();
    }

    /**
     * 获取锁
     * @param  String  $key    锁标识
     * @param  Int     $expire 锁过期时间
     * @return Boolean
     */
    public function lock($key, $expire = 5)
    {
        $is_lock = $this->_redis->setnx($key, time() + $expire);

        // 不能获取锁
        if (!$is_lock) {

            // 判断锁是否过期
            $lock_time = $this->_redis->get($key);

            // 锁已过期，删除锁，重新获取
            if (time() > $lock_time) {
                $this->unlock($key);
                $is_lock = $this->_redis->setnx($key, time() + $expire);
            }
        }

        return $is_lock ? true : false;
    }

    /**
     * 释放锁
     * @param  String  $key 锁标识
     * @return Boolean
     */
    public function unlock($key)
    {
        return $this->_redis->del($key);
    }

    /**
     * 创建redis连接
     * @return Link
     */
    private function connect()
    {
        try {
            $redis = new Redis();
            $redis->connect($this->_config['host'], $this->_config['port'], $this->_config['timeout'], $this->_config['reserved'], $this->_config['retry_interval']);
            if (empty($this->_config['auth'])) {
                $redis->auth($this->_config['auth']);
            }
            $redis->select($this->_config['index']);
        } catch (RedisException $e) {
            throw new Exception($e->getMessage());
            return false;
        }
        return $redis;
    }

}