PHP Cookies – How to Create, Set, Read & Delete a Cookie in PHP

PHP Cookies – How to set, read and delete a cookie in PHP?

HTTP is a stateless protocol. It means user sends a request, a server responds to that request without remembering the request later. To track important information (such as user preference, user activity etc.) on a website cookies are very useful. In this blog post, You are going to learn what is a cookie and How to create, set, read and delete a cookie in PHP.

What is Cookie?

Cookies are very useful to store small information in a remote browser (user browser). It’s a simple text file which stores maximum 4KB of data.

Cookies are created by a browser on the request of a server (as per program logic). Once a cookie is created on a user browser, the browser sends that cookie information back to the server using HTTP Header.

Why Cookie?

HTTP is a stateless protocol, so there is no way to track user’s previous activities on a website. Cookies are the best way to store the stateful information like the number of time user visited on a website, product viewed by a user, their preference etc.

PHP Cookies

I have explained what is a cookie and their importance. Let’s learn how to set a cookie in PHP.

In PHP setcookie() method is used to set a cookie in a user browser.

Syntax to set a cookie in PHP–

name – Defines the name of a cookie.

value – What value we want to store in a cookie. A Cookie always stores a string value.

How to store an array value in a cookie

time (optional field) – Set the cookie expiration date. If this field is empty then the cookie will be deleted when a browser is closed.

domain (optional field) – Set the domain in which a cookie is available. If you want to set a cookie for multiple subdomains, then use the name of main domain with a dot as a prefix.

For example –

Suppose webrewrite.com has multiple subdomains such as tech.webrewrite.com, education.webrewrite.com.  And I want a cookie set by webrewrite.com can be accessible to all of my subdomains then I set the domain as .webrewrite.com.

secure (optional field) – It Specifies whether or not a cookie should be transmitted over a secure HTTPS connection. By default secure option is FALSE. If it is TRUE it means cookie will only be set if a secure connection exists.

A Cookie is created with the name of a firstcookie with a value of studentduniya.

NOTE – A Cookie can only store string values. It can’t store an array. To store an array in a cookie, you need to first convert them into a string.

How to store & retrieve an array value from a cookie

NOTE: I have not set the time of this cookie, so it will expire when I close my browser.

With a setcookie() method a cookie will be set. Once a cookie is set, you can check the cookie on a chrome developer tool or if you are usingMozilla then you can use firebug.

Cookies in PHP

We have not defined the expiration time of a cookie. Let’s set a cookie for 30 days. In this case, We need to mention the time, so that cookie still remain for 30 days until a user deleted them manually.

How to set a cookie for multiple subdomains

How to Get the Value of a Cookie in PHP

In PHP, $_COOKIE is used to get the value of a cookie. So how do we read the value of a cookie which we set earlier?

How to Delete a Cookie in PHP

To delete a cookie in PHP, set the negative time (past time).

So what happens if we set negative time. In that case, a cookie will expire automatically.

Important Points About Cookies

1. Cookies can store maximum up to 4 KB of data.

2. It can only store a string.

3. Cookies can only be accessed by the browser that set them. Cookie set by chrome browser cannot be accessed by a Mozilla browser.

4. Try to avoid storing sensitive and confidential data in cookies.

Recommended Books for PHP

PHP Books on Flipkart

PHP Books on Amazon India

Conclusion

I tried my best to explain the concept of a PHP cookies. If I miss any point or you want to add something you can let me know by your comments.