php SESSION入庫的實現

session入庫,就是重寫session制機,在session的週期內,得到到session的數據並記錄到數據庫php

 Session默認是存放到服務器上的文件中,不方便管理,若是能把session存放到數據庫中就能夠方便的對數據庫進行管理了html

好比:mysql

session入庫能夠解決哪些問題?sql

1.      能夠解決跨域操做數據庫

2.      能夠實現單點登錄跨域

3.      能夠統計在線人數服務器

4.      能夠實現同一時只容許一個用戶在線session

 

session_set_save_handler的回掉函數描述yii

 

實現session入庫函數

       第一步:在php.ini配置文件中設置session.save_headler=user(默認是file)

                     或者使用ini_set設置ini_set(‘session.save_handler’,’user’);

       第二步:建立一個存放session的數據表

              session_id用於存放session_id的,字段類型爲字符型,長度爲32

              session_value用於存放session的內容,字段類型爲text

    session_life   用於存放session的生存期

        第三步:session_set_save_handler ( callback $open , callback $close ,callback $read , callback $write , callback $destroy , callback $gc )

     第四步:代碼實現

<?php
header('content-type:text/html;charset=utf-8');

//將session存儲方式設置爲存入數據庫的方式
//session.save_handler = files
ini_set("session.save_handler", "user");

session_set_save_handler("open", "close", "read", "write", "destroy", "gc");

//打開並鏈接數據庫
function open()
{
    //使用pdo
    $pdo = new PDO('mysql:host=127.0.0.1;dbname=yii','root','root');
    $pdo->exec('set names utf8');
}

//關閉鏈接
function close()
{
    //使用pdo
    $pdo = new PDO('mysql:host=127.0.0.1;dbname=yii','root','root');
    $pdo->exec('set names utf8');
    $pdo = null;
}

//從表中中讀信息
function read($session_id)
{
    //使用pdo
    $pdo = new PDO('mysql:host=127.0.0.1;dbname=yii','root','root');
    $pdo->exec('set names utf8');
    $read = $pdo->query("select * from session where session_id='$session_id'")->fetch(PDO::FETCH_ASSOC);
    return $read["session_info"];
}

//將session存入數據庫
function write ($session_id,$session_info)
{
    // echo $session_id. "        " . $session_info;
    //使用pdo
    $pdo = new PDO('mysql:host=127.0.0.1;dbname=yii','root','root');
    $pdo->exec('set names utf8');
    $read = $pdo->query("select * from session where session_id='$session_id'")->fetch(PDO::FETCH_ASSOC);

    if(empty($read))
    {
        $time = time();
        $pdo->exec("insert into session (session_id, session_info, session_life) values ('$session_id', '$session_info', '$time')");
    }
    else
    {
        $sql = "update session set session_info='$session_info' where session_id='$session_id'";
        $pdo->exec($sql);
    }
}

//銷燬指定session
function destroy($session_id)
{
    //使用pdo
    $pdo = new PDO('mysql:host=127.0.0.1;dbname=yii','root','root');
    $pdo->exec('set names utf8');
    $pdo->exec("delete from session where session_id='$session_id'");
}

//刪除全部過時的session
function gc()
{

}

session_start();
//判斷是否有session
if(isset($_SESSION['name']))
{

    $status = 1;
}
else
{
    $status = 0;

}

//獲取須要接收的值
$user_name = isset($_POST['user_name'])?$_POST['user_name']:null;
$user_pwd = isset($_POST['user_pwd'])?$_POST['user_pwd']:null;
//使用pdo
$pdo = new PDO('mysql:host=127.0.0.1;dbname=yii','root','root');
$pdo->exec('set names utf8');
$sql = "select * from user where username = '$user_name' and password = '$user_pwd' ";
$re = $pdo->query($sql)->fetch(PDO::FETCH_ASSOC);
if($re)
{
    $status = 1;
    $_SESSION['name'] = $user_name;
}

?>

 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
<?php if($status == 0){?>
    <h3>服務器3</h3>
    <form action="a.php" method="post">
        <table>
            <tr>
                <td>姓名:</td>
                <td><input type="text" name="user_name"></td>
            </tr>
            <tr>
                <td>密碼:</td>
                <td><input type="password" name="user_pwd"></td>
            </tr>
            <tr>
                <td></td>
                <td><input type="submit" value="登陸"></td>
            </tr>
        </table>
    </form>
<?php } else{?>
    <h2>歡迎<?=$_SESSION['name']?>登陸</h2>
    <h3>服務器3</h3>
<?php }
?>
</body>
</html>
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