PHP Cookies

What are Cookies in PHP?

Cookies are small text files stored on the client's computer by the web browser. They are used to remember information about the user, such as login information or site preferences, across sessions.

In PHP, cookies are created using the setcookie function. They can store data for a specified period, making them a useful tool for maintaining user state across multiple page requests.

Creating a Cookie with setcookie

The setcookie function is used to send a cookie from the server to the client's browser. The basic syntax is as follows:

• name: The name of the cookie.
• value: The value stored in the cookie.
• expire: The time the cookie expires, specified in seconds since the Unix Epoch.
• path: The path on the server where the cookie will be available.
• domain: The domain that the cookie is available to.
• secure: Indicates if the cookie should only be transmitted over a secure HTTPS connection.
• httponly: When true, the cookie will be made accessible only through the HTTP protocol.

Retrieving Cookie Values in PHP

Once a cookie has been set, it can be accessed using the $_COOKIE superglobal array in PHP. Here's how you can retrieve the value of a cookie:

Using SameSite Attribute for Cookie Security

The SameSite attribute enhances cookie security by allowing developers to declare if their cookies should be restricted to first-party or same-site contexts. This helps mitigate the risk of cross-site request forgery (CSRF) attacks.

PHP 7.3 introduced support for setting the SameSite attribute using an associative array:

Best Practices for Using Cookies

• Always set the secure flag to ensure cookies are transmitted over HTTPS.
• Use the httponly flag to prevent cookies from being accessed via JavaScript.
• Implement the SameSite attribute to safeguard against CSRF attacks.
• Regularly review and manage the expiration times of cookies to balance user convenience and security.