PHP : How to use Cookies

What Will I Learn?

This tutorial is all about how to set and get PHP cookies for remote browsers.

• What is a cookie?
• How to set a cookie?
• Difference between setcookie and setrawcookie.
• How to get a cookie?
• How to remove a cookie?

Requirements

• PHP Server
• Basic knowledge about PHP

Difficulty

• Basic

Tutorial Contents

What is a Cookie?

Cookies are messages that contains information about the user's browsers. This is use to track and identify users. On some websites, these cookies are used to store personal information of the user.

How to set a cookie?

There are two ways to set a cookie. You can use setcookie() or setrawcookie().

setcookie() function defines a cookie that will be sent along with the HTTP headers. So this function should be use before the HTML tag. And also this function will automatically encode the data using URLEncoding when sending the cookie to the user's browser and decoded it when received from the server. The syntax for this function is this:

setcookie ( string $name [, string $value = "" [, int $expire = 0 [, string $path = "" [, string $domain = "" [, bool $secure = FALSE [, bool $httponly = FALSE ]]]]]] )

Example:

<?php 
     setcookie('Name', 'Gentlemanoi');
?>

So here, we can see that there is a cookie on the request and response header after we set the cookie.

The setrawcookie() function is just like setcookie() but without URLEncoding. So the data that will be sent to the browser and receive from the server are raw data. It means that the data that you will set will be the actual data that will be sent or received. The syntax for this function is this:

setrawcookie ( string $name [, string $value [, int $expire = 0 [, string $path [, string $domain [, bool $secure = FALSE [, bool $httponly = FALSE ]]]]]] )

Example:

<?php
     setcookie('Name', 'Gentlemanoi');
     setrawcookie('Nickname', 'gentleman');
?>

And here you can see that we already have two cookies (Name, Nickname).

The main difference between the two functions is the URLEncoding. So if you have an already encoded cookie you can use setrawcookie() to avoid double encoding.

How to get a cookie?

To get a cookie, you can use the Cookie global variable of PHP. The syntax will be like this:

<?php
     $_COOKIE['Name'];
?>

Please note that the cookie global variable cannot be used to set a cookie. The example below is INVALID:

<?php
     $_COOKIE['Name'] = 'Gentlemanoi'; //This is invalid!
?>

You can also use isset() function to check if the cookie is available.

<?php
    if(isset($_COOKIE['Name'])){
          echo $_COOKIE['Name'];
    }
?>

How to remove a cookie?

Deleting a cookie is just like setting a cookie. To remove a cookie, you also have to use the setcookie function with a third parameter(the expiration date).

Example:

<?php
    setcookie('Name', '', time() - 3600); //set to one hour ago
?>

You only have to set the expiration date to a value that is before the current time.

Curriculum

• PHP : How to use ZipArchive class
• PHP : How to check if a string contains a specific word/string
• PHP7 : How to use Null Coalescing Operator

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