Session and Cookies in PHP

This article will let you know about Session and Cookie in PHP. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to everyone.

1. Implement session processing through Session and Cookie

1. The HTTP protocol is stateless

The server cannot distinguish which requests come from which clients, or whether the client is connected or disconnected

2. Session

During a period of time when the user accesses the web page and is disconnected from the server , Session can track the user's status

3. Cookie

is a text file, which is located on the client. This file stores session information

2. What is Session

1. Session is a session that records session information so that the session between the client and the server can be maintained

2. Create a session

$_SESSION['name'] = 'wuhenzhiyi'

3. Commonly used functions of Session

1. Creation of Session

session_start() Means the beginning of a session

2. Destruction of Session

• session_unset() Delete a specified session

• session_destroy( ) Delete the entire session

//开启一个会话
session_start();

//创建一个会话
$_SESSION['name'] = 'wuhenzhiyi';

//访问一个会话
echo $_SESSION['name'];//输出 wuhen

//删除指定的会话
session_unset($_SESSION['name']);

//删除全部会话
session_destroy();

4. What is Cookie

1. Cookie is a website that distinguishes the identities of different visitors and is stored on the client. The data on is a text file.

5. Cookie working mechanism

1. When the client requests the server for the first time, the server has a cookie setting statement, and the server sends a cookie with the response. Set-Cookie of HTTP, sets a Cookie file on the client

2. When the client sends an HTTP request to the server again, the browser will send the Cookie information that locally saves the request address to the server. The server will read it automatically.

6. Creation and destruction of Cookie

1. setcookie() creates a cookie

2.setcookie() function and header() function Similarly, it is also sent as part of the response header

3. Therefore, there cannot be any output before calling this function

4. Because the cookie is sent with the header, when we set After the cookie is set, it will not take effect on this page.

5. Delete cookies

Set its value to empty, or set the validity period to the past time

//创建一个cookie
//设置一个有效期为7天的cookie
setcookie('name','wuhenzhiyi',time()+60*24*7);

//访问一个cookie
echo $_COOKIE['name'];

//删除cookie
setcookie('name','');

//或者设置过期时间为过去的时间
setcookie('name','',time()-1);

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