 PHP Page 3 - Login and Logout Authentication for a Project Management Application |
The Logout Form - PHPIn this article we continue to look at the login and logout scripts of the project management application. We ended the previous article by looking at the PHP code of the login script. In this article we will be looking at the HTML login form and the logout script.
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The code below does the actual logging out by simply destroying any sessions or session variables that have been set up. First it calls the ob_start() function before including the usual database connection file(dbcon.php) and functions.php. <? ob_start(); include "dbcon.php"; //update the users table The ob_start() function allows you to write and execute your scripts as normal but send data to the web browser only at select points. The chief benefit of this is that it enables you to call the session_start() function without having to worry about the dreaded headers already sent error message. We make doubly sure that the session is actually active by checking to see if the name session variable is set. if(isset($_SESSION['name'])){ If so, we first update the users table’s last_login field with today's date, stored in the $td variable. The $td variable is contained in the dbcon.php file that is included at the top. Here are its contents. <? session_start(); $title = "Project Management"; //database connection $db = mysql_connect("localhost") or die("Failed to open connection to MySQL server."); mysql_select_db("project_management") or die("Unable to select database"); //set useful variables $month_names = array("","January","February","March","April","May","June","July","August", //set useful variables $td = date("Y-m-d"); $date_time =date("Y-m-d h:i:s"); ?> The $td variable contains today's date in the format year-month-date, which is the format used by MySQL. The update query is run like so: $uname =$_SESSION['name']; $save = "UPDATE users SET last_login ='".$td."'"; mysql_query($save); Then the sessions are destroyed like so: //destroy session session_start(); session_unset(); session_destroy(); }else{ If the name session variable is not set, then we redirect the user to the login page. //user is not suppose to be on this page //redirect to login page header("location:login.php"); } ?> The HTML part of the logout script simply displays the "you are now logged out" message and offers the user a login link. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"><!-- InstanceBegin template="/Templates/userauth.dwt.php" codeOutsideHTMLIsLocked="false" --> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <!-- InstanceBeginEditable name="doctitle" --> <title>Project Management::Logout</title> <!-- InstanceEndEditable --> <!-- InstanceBeginEditable name="head" --><!-- InstanceEndEditable --> <link href="Templates/loginstyle.css" rel="stylesheet" type="text/css" /> </head> <body> <table width="100%" border="0"> <tr> <td bgcolor="#6699CC" class="headertxt">Project Management:: User Authentication </td> </tr> <tr> <td><!-- InstanceBeginEditable name="main" --> <table width="100%" border="0"> <tr> <td width="33%"> </td> <td width="30%"> </td> <td width="37%"> </td> </tr> <tr> <td colspan="3"><div align="center" class="loginheader"><strong><?php echo $uname.",";?></strong> you are now logged out. </div></td> </tr> <tr> <td colspan="3"><div align="center" class="loginheader">Click <a href="login.php">here</a> to login </div></td> </tr> </table> <!-- InstanceEndEditable --></td> </tr> <tr> <td align="right" class="cright">copyright © 2007 PM </td> </tr> </table> </body> <!-- InstanceEnd --></html>
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