What is Session in php –:Cookies are stored on browser window means it stored on user side. it is possible for a hacker to easily hack the cookie content to insert potentially harmful data in your application that might break your application.
Also every time the web browser requests a url to the server.All the cookie data for a website is automatically sent to the server within the request. It means if you have stored 10 cookies on user’s system, each having 8 KB in size, the browser needs to upload 40 KB of data each time the user views a page.This will definitely affect your site’s performance.
The solution of this problem in php session. It stores data on the server side . A session based environment every user is identified through a unique number called session identifier or (SID). This unique session ID is used to link each user with their own information on the server like emails, posts, etc.
Create a session in php-: Before you start to create a session it is necessary to know that a php engine automatically created a session in php.
In the php you can use function for creating a session variable. we can use session_start() function for creating a session for example
<?php session_start(); // for start a session in php ?> <html> <body> <?php // Set session variables $_SESSION["authorname"] = "Vikram"; $_SESSION["favoritefield"] = "Software"; echo "Session variables name are set"; ?> </body> </html>
Output of this program
Session variables are set
how to Get session in php-: After creating a session we get this session.For getting this session we use this syntax as like
<?php session_start(); // for start a session in php ?> <html> <body> <?php // Echo session variables that were set on previous page echo "author name is" . $_SESSION["authorname"] . ".<br>"; echo "Favorite field is" . $_SESSION["favoritefield"] . "."; ?> </body> </html>
Output of this program
author name is vikram favorite field is software
Modify a session in php -: For editing in session or modify session we can create this function print_r($_SESSION)
<?php $_SESSION["favoritefield"] = "software"; print_r($_SESSION); ?>
Delete a session in php –: Delete a session in php we use session_destroy() function. For example
<?php
session_start(); // for start a session in php
?>
<html>
<body>
<?php
session_destroy(); //delete a session
echo "all session are delete";
?>
</body>
</html>
Output of this program
all session are delete