Web Database Applications with PHP, and MySQL

Managing Redirection

The cart.5 script shown in Example 11-6 is a central point that manages redirection to other scripts in the winestore. All pages that have more than one button request this script using the action attribute of the <form> element. The script processes the requests, determines from the GET method attributes which script should be requested next, and then redirects the browser to that script.

For example, if the user clicks the Empty Cart button on any page, the following URL is requested:

http://localhost/example.cart.5.php?empty=Empty+Cart

The cart.5 script is then processed, the following if test is found to be true, and the script redirects to the cart.4 script:

// Did they want to empty the cart?
if (!empty($parameters["empty"]))
{
   // Redirect the browser to the empty page
   // using the HTTP response header "Location:"
   header("Location: example.cart.4.php");
   exit;
}

When redirecting to some scripts, the redirection also passes on the entire QUERY_STRING—the query string is stored in the PHP environment variable $QUERY_STRING—as a GET method parameter. In addition, a session variable, referer, is registered in selected cases so that in later processing the script can redirect to the original calling page.

As discussed in Chapter 10, there are several other possible approaches for managing requests for different scripts throughout an application. An alternative to the approach is to add each button to the HTML page as a separate <form> element with its own ...