PHP Sessions

A session is a way to store information (in variables) to be used across multiple pages. Unlike cookies, session data is stored on the server, which makes it more secure.

1. Starting a Session

To use sessions in PHP, you must first start the session using session_start(). This function must be placed at the top of the page before any HTML output.

<?php
session_start();
?>

2. Creating Session Variables

Session variables are stored in the $_SESSION superglobal array.

<?php
  session_start();
  $_SESSION["username"] = "ExpertAdmin";
  $_SESSION["email"] = "admin@example.com";
  echo "Session variables are set.";
?>

3. Accessing Session Variables

You can access session variables on other pages after calling session_start().

<?php
  session_start();
  echo "Username: " . $_SESSION["username"];
  echo "<br>";
  echo "Email: " . $_SESSION["email"];
?>

4. Checking if Session Exists

Use isset() to check whether a session variable is set.

<?php
  session_start();
  if(isset($_SESSION["username"])) {
    echo "Session is active";
  } else {
    echo "No active session found";
  }
?>

5. Destroying a Session

To remove all session variables and destroy the session, use session_unset() and session_destroy().

<?php
  session_start();
  session_unset();
  session_destroy();
  echo "Session destroyed successfully.";
?>

Important: Always call session_start() at the very beginning of your PHP file. Session data is stored on the server, which makes it more secure than cookies.