[grace55]

PHP SESSIONS

When your websites start to become more advanced and you find that you have a need for specific user data to be available throughout different pages on your website (think shopping cart!), it’s time for Sessions!
Starting a session is a snap.

<?php
session start();
?>

The webserver will attach a really really long random “session ID” to indicate a unique session. It looks something like: a8486dd2a3eacc136bd44ca653d8c5a2
A session isn’t worth a hill of beans unless we can store data in it. Fortunately, PHP can do this for us with an associative
array, based on the $_SESSION variable. (Is some of this starting to come together?)
Let’s make a login form based on sessions!

<?php
session_start(); // Starts a PHP session
echo "<form method=POST action=index.php>
User Name: <input type=text name=\"username\">
Password: <input type=text name=\"password\">
<input type=submit>
</form>"; // This is the HTML form
$_SESSION['username']=$_POST["username"]; // Enters the username into the array
$_SESSION['password']=$_POST["password"]; // Enters the password into the array
?>

Your username and password are now stored in an array that will last until the session is “un-set”.
Removing a session is done when either: The viewer closes their browser, or PHP runs the command to un-set a session, aka “destroy”.
You can think of it like this - your session is an Etch-a-Sketchtm that has information drawn on it. It’s there until you shake it!

<?php
session_destroy();
?>

Yes, it’s a tad violent...but gets the job done. This will clear out any data associated with the current session.
So, what if I want to remove specific data from a session without deleting the whole thing?
This can be done with an IF statement combined with commands called “ISSET” and “UNSET”.

<?php
if(isset($_SESSION['items'])){
unset($_SESSION['items']);}
?>

So, logically...
If this specific key is set in this session, remove the key’s data.