Solved: start session if not started

Starting a session in PHP is one of the first fundamental steps in setting up a login system in a website. These are important to provide personalization, where based on the user that has logged in, the server presents custom options and settings. PHP has built-in session handling techniques to manage this effectively. Sessions in PHP make it possible to save data about visitors and use this information across various pages. PHP offers developers tools to start and manage sessions easily, but it’s crucial to understand their proper implementation to avoid common pitfalls and bugs.

What are Sessions?

A session starts as a visitor navigates pages on a website. Each unique visitor gets assigned a unique identifier (session ID). This information forms the basis for user data storage on the server, identifiable via its corresponding session ID. Without sessions, users wouldn’t enjoy personalized web content – a necessary tool in today’s online world.

Starting A Session in PHP

To start a session in PHP, we use the session_start() function. This function first verifies whether a session is already started with the same session ID in use. If it finds one, it resumes the session. Else, it starts a new session.

Here’s the basic implementation:

    if(session_status() !== PHP_SESSION_ACTIVE) {

The session_status() function used in the if statement checks the status of the session. If a session isn’t active, then session_start() is executed. This piece of code helps in preventing possible error messages indicating an already started session.

A Detailed Breakdown of the Code

In the PHP script, the session_status() function checks the status of the session. The PHP_SESSION_ACTIVE is a built-in constant that holds the return value of session_status() when the session is active. The ! operator is a logical operator indicating ‘not.’ Therefore, if the session_status() does not equal PHP_SESSION_ACTIVE (i.e., the session is not active), the session_start() function runs.

This function is necessary for using sessions. It must occur before the HTML document type declaration. The session_start() function creates a new session or resumes an existing one. Once the session starts, you can store and retrieve values for the user.

Mind that in case of redirect or require/include functionality, you should call session_start() to every page where you want to read, write or modify session variables.

Managing Sessions

After initiating a session, PHP provides other functions to manipulate and handle the sessions effectively. For instance, you can set session variables, destroy a session and so on.

    //start the session

    //set a session variable
    $_SESSION&#91;'username'&#93; = 'John Doe';

    //retrieve a session variable
    $username = $_SESSION&#91;'username'&#93;;

    //destroy a session

In this sample script, a session is started and a session variable ‘username’ is set. The session variable can be retrieved and used later in your script. Finally, the session is destroyed using session_destroy().

Learning session handling in PHP is crucial to web development as it allows customization and personalization to the user’s experience. By following these steps, you’ve not only learnt how to start a session in PHP, but also what sessions are, and how to manage them.

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