PHP method of processing session based on redis_javascript skills

A redis-based method for processing sessions, as follows.

<&#63;php
class Session_custom {
  private $redis; // redis实例
  private $prefix = 'sess_'; // session_id前缀
  
  // 会话开始时，会执行该方法，连接redis服务器
  public function open($path, $name) {
    $this->redis = new Redis();
    return $this->redis->connect("127.0.0.1",6379);
  }
  
  // 会话结束时，调用该方法，关闭redis连接
  public function close() {
    $this->redis->close();
    return true;
  }
  
  // 会话保存数据时调用该方法，在脚本执行完或session_write_close方法调用之后调用
  public function write($session_id, $data) {
    return $this->redis->hMSet($this->prefix.$session_id, array('expires' => time(), 'data' => $data));
  }
  
  // 在自动开始会话或者通过调用 session_start() 函数手动开始会话之后，PHP 内部调用 read 回调函数来获取会话数据。
  public function read($session_id) {
    if($this->redis->exists($this->prefix.$session_id)) {
      return $this->redis->hGet($this->prefix.$session_id, 'data');
    }
    return '';
  }
  
  // 清除会话中的数据，当调用session_destroy()函数，或者调用 session_regenerate_id()函数并且设置 destroy 参数为 TRUE 时,会调用此回调函数。
  public function destroy($session_id) {
    if($this->redis->exists($this->prefix.$session_id)) {
      return $this->redis->del($this->prefix.$session_id) > 0 &#63; true : false;
    }
    return true;
  }
  
  // 垃圾回收函数，调用周期由 session.gc_probability 和 session.gc_divisor 参数控制
  public function gc($maxlifetime) {
    $allKeys = $this->redis->keys("{$this->prefix}*");
    foreach($allKeys as $key) {
      if($this->redis->exists($key) && $this->redis->hGet($key, 'expires') + $maxlifetime < time()) {
        $this->redis->del($key);
      }
    }
    return true;
  }
}

// 调用自定义的session处理方法
$handler = new Session_custom();
session_set_save_handler(
  array($handler, 'open'),
  array($handler, 'close'),
  array($handler, 'read'),
  array($handler, 'write'),
  array($handler, 'destroy'),
  array($handler, 'gc')
);

// 下面这行代码可以防止使用对象作为会话保存管理器时可能引发的非预期行为,表示当脚本执行之后或调用exit()之后，存储当前会话数据并关闭当前会话
register_shutdown_function('session_write_close');

session_start();

// 可以使用session了

Supplement:

The two configuration options session.gc_probability and session.gc_divisor in the php.ini file jointly determine the timing of the gc function call. The default value is divided into 1 and 1000, which means that each request has only 1/1000 chance to call the gc function.

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