About the implementation of adding redis to session

This article mainly introduces the instance of adding session to redis, introduces the session in detail, and provides code examples. Friends in need can refer to the following

Session information into redis

Session Introduction

session, often translated as conversation in Chinese, its original meaning refers to a series of actions/messages that have a beginning and an end, such as picking up the phone when making a phone call The series of processes from dialing to hanging up can be called a session. Sometimes we can see words like "During a browser session,..." The word session here is used in its original meaning, which refers to the period from the opening to closing of a browser window①. The most confusing thing is the sentence "the user (client) during a session", which may refer to a series of actions of the user (generally a series of actions related to a specific purpose, such as from logging in to purchasing goods). The online shopping process from checkout to logout is sometimes called a transaction). However, sometimes it may just refer to a connection, or it may refer to meaning ①. The difference can only be inferred from the context ②.

In this article, the Chinese "browser session period" is used to express the meaning ①, the "session mechanism" is used to express the meaning ④, the "session" is used to express the meaning ⑤, and the specific "HttpSession" is used To express the meaning ⑥

Why should SESSION be saved in the cache

As far as php is concerned, the session supported by the language itself is in the form of a file Save to a disk file and save it in the specified folder. The saved path can be set in the configuration file or using the function session_save_path() in the program. However, there are drawbacks to this.
The first is to save to a file In the system, the efficiency is low. As long as the session is used, the specified sessionid will be searched from multiple files, which is very inefficient.
The second is that when multiple servers are used, the problem of session loss may occur (actually it is saved on other servers).
Of course, saving in the cache can solve the above problem. If you use PHP's own session function, you can use the session_set_save_handler() function to easily re-control the session processing process. If you don't use PHP's session series functions, you can write a similar session function yourself, which is also possible. This is the project I'm working on now. It will calculate the hash as the sessionId based on the user's mid and login time. Each time it is requested, The sessionId must be added to be legal (it is not needed when logging in for the first time, the sessionId will be created at this time and returned to the client). This is also very convenient, concise and efficient. Of course, what I am mainly talking about in this article is "manipulating things" in PHP's own SESSION.

SESSION is saved in the cache

php saves the cache to redis. You can use the configuration file to modify the processing and saving of the session. , of course, you can also use the ini_set() function to modify it in the program. This is very convenient for testing. I will use this method here. Of course, if it is a production environment, it is recommended to use the configuration file.

If you want to simply operate the session into redis, you can run the following code

<?php 
 
ini_set("session.save_handler", "redis"); 
 
ini_set("session.save_path", "tcp://localhost:6379"); 
 
session_start(); 
 
header("Content-type:text/html;charset=utf-8"); 
 
if(isset($_SESSION[&#39;view&#39;])){ 
 
  $_SESSION[&#39;view&#39;] = $_SESSION[&#39;view&#39;] + 1; 
 
}else{ 
 
  $_SESSION[&#39;view&#39;] = 1; 
 
} 
 
echo "【view】{$_SESSION[&#39;view&#39;]}"; 
 
//这里设置session.save_handler方式为redis，session.save_path为redis的地址和端口，设置之后刷新，再回头查看redis，会发现redis中的生成了sessionId，sessionId和浏览器请求的是一样的， 
 
  
 
//也可以使用 
 
Session_set_save_handler(‘open&#39;,&#39;close&#39;,&#39; read&#39;,&#39; write&#39;,&#39; destory&#39;,&#39; gc&#39;); 
 
//用法如下自定义一个Redis_session类 
 
<?php 
 
class RedisSession{ 
 
  private $_redis = array( 
 
    &#39;handler&#39; => null, //数据库连接句柄 
 
    &#39;host&#39; => null,  //redis端口号 
 
    &#39;port&#39; => null, 
 
  ); 
 
  public function __construct($array = array()){ 
 
    isset($array[&#39;host&#39;])?$array[&#39;host&#39;]:"false"; 
 
    isset($array[&#39;port&#39;])?$array[&#39;host&#39;]:"false"; 
 
    $this->_redis = array_merge($this->_redis, $array); 
 
  } 
 
  public function begin(){ 
 
    //设置session处理函数 
 
    session_set_save_handler( 
 
      array($this, &#39;open&#39;), 
 
      array($this, &#39;close&#39;), 
 
      array($this, &#39;read&#39;), 
 
      array($this, &#39;write&#39;), 
 
      array($this, &#39;destory&#39;), 
 
      array($this, &#39;gc&#39;) 
 
    ); 
 
  } 
 
  public function open(){ 
 
    $redis = new Redis(); 
 
    $redis->connect($this->_redis[&#39;host&#39;], $this->_redis[&#39;port&#39;]); 
 
    if(!$redis){ 
 
      return false; 
 
    } 
 
  
 
    $this->_redis[&#39;handler&#39;] = $redis; 
 
    $this->gc(null); 
 
    return true; 
 
  } 
 
  //关 
 
  public function close(){ 
 
    return $this->_redis[&#39;handler&#39;]->close(); 
 
  } 
 
  //读 
 
  public function read($session_id){ 
 
    return $this->_redis[&#39;handler&#39;]->get($session_id); 
 
  } 
 
  //写 
 
  public function write($sessionId, $sessionData){ 
 
    return $this->_redis[&#39;handler&#39;]->set($sessionId, $sessionData); 
 
  } 
 
  public function destory($sessionId){ 
 
    return $this->_redis[&#39;handler&#39;]->delete($sessionId) >= 1 ? true : false; 
 
  } 
 
  public function gc(){ 
 
    //获取所有sessionid，让过期的释放掉 
 
    $this->_redis[&#39;handler&#39;]->keys("*"); 
 
    return true; 
 
  } 
 
} 
 
$ses = new RedisSession(array(&#39;host&#39;=>&#39;127.0.0.1&#39;,&#39;port&#39;=>&#39;6379&#39;)); 
 
$ses->begin(); 
 
session_start(); 
 
$_SESSION[&#39;name&#39;]=&#39;zhangsan&#39;; 
 
echo $_SESSION[&#39;name&#39;];

In this way, you can realize the session data such as the redis code execution process Redis must be installed in it.

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