Cookies in PHP

How to use cookies in PHP

 

Table of Contents

1. What is Cookie?
2. Creating Cookie
3. How to View Cookies?
4. Retrieving Cookie
5. Removing Cookie

 

What is Cookie?

Basically a cookie used to store client data. The website identifies a user with this data.

•   A cookie is a small variable that the server embeds on the user's computer.
•   When a page request comes from the user, the server also sends a cookie to the browser along the page URL.
•   Using PHP, we can create and retrieve cookie values.

  

 PHP Cookies:

Cookie is a super global variable. It is an  associative array and stores user information in the form of name value pairs.  Cookie information available to all pages on the website.

Creating Cookie:

Syntax:

setcookie(cookie_name, cookie_value, expire)
setcookie(cookie_name, cookie_value, expire, path, domain);

Example:
setcookie("user", "Shashankh", time()+3600);

expiration time is set to 1hour. current time plus 3600 milliseconds. So the lifetime of the cookie is one hour. After that, the cookie was deleted. Default time of the cookie is 30 days or as set in the browser. However, it is the user choice, he can delete cookies any time.

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Code Example:

cookie.php

<?php

 
setcookie("user", "Shashankh", time()+3600);

?>

setcookie creates a cookie 'user'. To view cookies in the browser, there are several ways. It depends on the browser that you are using

How to View Cookies?

In this example we are using Chrome browser. To view cookie information in chrome, just follow the steps given below. 

• Click on Customize and control the chrome  menu option in the top right corner of the chrome.
• Select More tools and select Developer tools 
• Select Application tab and Cookies from sidebar
• Select the Url and  right panel you will the cookies as shown in the 2nd image.

 

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Using Chrome:

 

 

Retrieving Cookie: 

 Cookies can be retrieved in PHP using inbuilt array called $_COOKIE.

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Code Example:

cookie.php

<?php

 
setcookie("user", "Shashankh", time()+3600);

echo "<br>".$_COOKIE['user'] ."<br>";
 

?>

output: 

Shashankh

Example2:

<?php

setcookie("user", "Shashankh", time()+3600);

setcookie("city", "hyderabad", time()+5);

 
echo "<br>".$_COOKIE['user'] ."<br>";

echo "<br>".$_COOKIE['city'] ."<br>"; 

?> 

output

Shashankh

Hyderabad

In the above example, the cookie variable 'city' will expire after 5 seconds automatically. When you refresh the browser, you will see an undefined variable error.

if refresh the browser  then you will see the following output.

Shashankh

Notice: Undefined index: city in C:\xampp1\htdocs\coding-zon\php-cookies\cookie.php on line 10

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Example3:

To view all cookies, use the following code.

<?php
 

print_r($_COOKIE);
 

?>

Removing Cookie: 

 Cookies can be removed in several ways.

1) Using setcookie

Example 1:

remove_cookie.php

<?php

setcookie("user", "Shashankh", time()+3600); 

echo "<br>".$_COOKIE['user'] ."<br>"; // cookie value displayed

 
setcookie("user", "", time()-3600);

echo "<br>Cookie deleted.."; 

echo "<br>".$_COOKIE['user'] ."<br>";  // error
 

?>

Example 2:

setcookie('user', '', 1); // 1 is just a sample time point in the past.

2) from the $_COOKIE using  unset() function

unset($_COOKIE['user']);

 

To know more on cookies, visit: PHP Manual

Conclusion:

Hopes You got some Idea on How to use Cookies in PHP. Please comment if  any doubts or questions regarding Cookies.

Happy Learning.

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