Storing Session Data | Spring Into PHP 5

You use the $_SESSION array to store data in a session. This array is a global variable just like $_POST, $_GET, and $_REQUEST. Note that you must start your session using session_start before you can use $_SESSION.

Here's an example, where we'll use session_start and then store some data in the session under the name temperature, setting it to 72:

 <?php     session_start();     $_SESSION['temperature'] = "72"; ?>

After storing that data in a session, we'll let the user move to another page, phpsession2.php, before recovering that data, so we'll also include a hyperlink to phpsession2.php in phpsession.php, as you can see in Example 9-12.

Example 9-12. Storing data in a session, phpsession.php

 <HTML>     <HEAD><TITLE>Storing data in sessions</TITLE></HEAD>     <BODY><CENTER>             <H1>                 Storing data in sessions             </H1>             <?php                 session_start();                 $_SESSION['temperature'] = "72";             ?>             Stored the temperature as 72 degrees.             <BR>             To read the temperature in a new page, <a href="phpsession2.php">                 click here</a>.         </CENTER><BODY> </HTML>

You can see this page at work in Figure 9-11, where we've stored the data in the session.

Figure 9-11. Storing data.

If the user navigates to phpsession2.php, Example 9-13, before the session expires, we'll be able to recover the stored data and display it. You can see the retrieved data displayed in phpsession2.php, Figure 9-12. Cool.

Example 9-13. Retrieving data in a session, phpsession2.php

 <HTML>     <HEAD>         <TITLE>             Retrieving data in sessions         </TITLE>     </HEAD>     <BODY>         <CENTER>             <H1>                 Retrieving data in sessions             </H1>             <?php                 session_start();                 if(isset($_SESSION["temperature"])){                     echo "Welcome. The temperature is " .                     $_SESSION['temperature'];                 }             ?>         </CENTER>     <BODY> </HTML>

Figure 9-12. Retrieving data.