PHP operates Session and Cookie

We need to use Session and Cookie when tracking user information, such as user login verification, recording user browsing history, storing shopping cart data, limiting user session validity time, etc. Today we will learn how PHP operates Session and Cookies.

Session

PHP's $_SESSION can store the current user data information. When a user accesses a WEB website, PHP will create a session ID for each visiting user. This ID is a unique ID and is stored on the client machine. The user's Session data is saved to the server. PHP can store each different user information. When the session expires, the user session information will also become invalid.

When using Session, when using PHP session, be sure to add session_start() to the header of the page to tell the server to start using the session, and there should be no output before it, otherwise an error will be reported.

  <?php 
session_start();  
  //PHP 代码...  ?>

PHP setting and getting Session

We can use PHP's $_SESSION to set and get Session data, such as:

<?php 
session_start();   
  //设置一个session值  $_SESSION["name"] = "Hello";  
  //将session以数组形式保存  $_SESSION["arr"] = array(&#39;name&#39; => &#39;Hello&#39;, &#39;url&#39; => &#39;http://www.helloweba.com&#39;, &#39;type&#39;=> &#39;website&#39;);  ?>

Once the Session data is stored, we can use the Session on the website, for example, we are on another page You can get the Session data:

 <?php 
session_start();   
  //获取保存的Session name   echo $_SESSION["name"]; 
  //打印数组session 
print_r($_SESSION["arr"]);  ?>

PHP Delete Session

When the Session is no longer used, we can use PHP to delete and clear the session data. The method is as follows:

<?php  unset($_SESSION["name"]);  ?>

If you want to clear all the Session information of the current user, you can use the following Code:

 <?php 
session_destroy();  ?>

Cookie

Cookie is a temporary file created on the current client computer by the website server visited by the user. It is used to save user information so that the website server can identify the user information when the user continues to visit the website next time. Common cookies are used to save user interface, user ID and other data.

PHP Set Cookie

We can use PHP's setcookie() to create cookies on the client. This function provides the main three parameters, cookie name, value and validity period.

<?php  $cookie_val = &#39;Chrome&#39;;  
setcookie("browser", $cookie_val, time()+3600);   ?>

Running the above code will create a cookie named Chrome and save it on the client for 1 hour. The cookie information will expire after 1 hour.

PHP receives Cookie

After the Cookie is created, we can easily get the cookie value, using PHP's $_COOKIE, the usage is as follows:

<?php  if(isset($_COOKIE[&#39;browser&#39;])) { 
    echo &#39;您的浏览器是：&#39; . $_COOKIE[&#39;browser&#39;]; 
}  ?>

PHP Delete Cookie

If you want to completely delete the save on your machine For cookie information, you can use the following code:

  <?php 
setcookie("browser", "", time()-3600);  ?>

The above code will clear the cookie named browser and set the validity period to 1 hour ago, completely clearing the cookie information.