Session with PHP

Today, I learned about the Session and header.

 

Session

A Session starts when you launch a website or web app and ends when you leave the website or close your browser window.

• Session allows you to maintain state information even when cllients disable cookies in their Web browsers.
• Session cookies contain information that is stored in a temporary memony location
• Session is known as transient cookies, non-persistent cookies, or temproary cookies

 

In PHP, how does session state work?

Starting a session

• You must call the session_start() function before you send the Web browser any output.
• PHP checks if there is already a session ID coming from a cookie! POSTed data, or query string
  • If ID exists then the data is read from the session's state file as name-value pairs and stored in the $_SESSION variable.
  • If there is no session ID, then session_start() generates a unique session ID to identify the session.

<?php
session_start();
?>

• If a client's Web browser is configured. to accept cookies, the session ID is assigned to a temporary cookie names PHPSESSID.
• The session ID maybe obtained from: session_id()

 

$_SESSION

• Session. state information is stored in the $_SESSION autoglobal.
• When the session start() is called, PHP either initializes a new $_SESSION autoglobal or retrieves any variabels for the current session (based on the session ID) into the $_SESSION autoglobal.

<?php
include_once("ShoppingCart.class.php");
session strat();

// check for existence of session object before accessing
if (isset($_SESSION["Cart"])){
	$_SESSION["Cart"] = new ShoppingCart();
}
$cart = $_SESSION["Cart"];
?>

 

Delete a Session

• To delete a session manually, perform the following steps:
  • Execute session_strat();
  • Use the session_destroy() to delete session
  • Modify the Registration/Log In page so it deletes any existing user session whenever a user opens it.

<?php
session_start();
session_destroy();
?>

 

Session Without Cookies

• If cookie is disabled, manually pass the session ID as a query string or hidden from field to any Web pages that are called as part of the current session
• The session ID maybe obtained from:  session_id()

<p><a href="sessionNoCookie.php?PHPSESSID=<?=session_id()?>">Visit again</a></p>
<p><a href="sessionNoCookie.php?<?=SID?>">Visit again</a></p>
<input type="hidden" name="PHPSESSID" value="<?= session_id() ?>"/>