[x70sef]

i have the following script which lets users log in to the website.

PHP Code:

<?php  

session_start();   

include 'dbc.php';  

$tbl_name="members"; // Table name   



// Connect to server and select databse.  

mysql_connect("$host", "$username", "$password")or die("cannot connect");   

mysql_select_db("$db_name")or die("cannot select DB");  



// username and password sent from form   

$myusername=$_POST['myusername'];   

$mypassword=$_POST['mypassword'];   



// To protect MySQL injection (more detail about MySQL injection)  

$myusername = stripslashes($myusername);  

$mypassword = stripslashes($mypassword);  

$myusername = mysql_real_escape_string($myusername);  

$mypassword = mysql_real_escape_string($mypassword);  



$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";  

$result=mysql_query($sql);  



if ($row = mysql_fetch_array($result)) 

{ 

// this sets variables in the session   

        $_SESSION['user'] = $myusername;   



         

        if ($row['mem_type'] == 'Student') 

        { 

            header("location:login_success.php");    

            exit ; 

        } 

        elseif ($row['mem_type'] == 'Teacher') 

        { 

            header("location:controlpanel.php");    

            exit ; 

        } 

         

}  

else {

echo "<font color=#005B99><font face=Calibri><center><h2>Wrong Username or Password </h2><br/>";  

echo "<h3>To re-enter username and password click <a href=\"main_login.php\">here</a></h3></center></font>";  

}  

?>

the problem is that the user can log on as many times as they like..

i want a message sayin ' username is already logged onto website ' how do i change the script to achieve this??

thanks in advance..

[job0107]

Well you could do it like this:

PHP Code:

<?php
session_start();
if(empty($_SESSION["user"])&&empty($_SESSION["password"]))
{
 $_SESSION["user"] = empty($_POST['myusername']) ? "" : mysql_real_escape_string(stripslashes($_POST['myusername']));
 $_SESSION["password"] = empty($_POST['mypassword']) ? "" : mysql_real_escape_string(stripslashes($_POST['mypassword']));
 include 'dbc.php';
 $tbl_name="members";
 mysql_connect("$host", "$username", "$password")or die("cannot connect");
 mysql_select_db("$db_name")or die("cannot select DB");
 $sql="SELECT * FROM $tbl_name WHERE username='".$_SESSION["user"]."' and password='".$_SESSION["password"]."'";
 $result=mysql_query($sql);
 if($row = mysql_fetch_array($result))
 {
  if($row['mem_type'] == 'Student')
  {
   header("location:login_success.php");
   exit;
   }
  elseif($row['mem_type'] == 'Teacher')
  {
   header("location:controlpanel.php");
   exit ;
   }
  }
 else
 {
  echo "<font color=#005B99><font face=Calibri><center><h2>Wrong Username or Password </h2><br/>";
  echo "<h3>To re-enter username and password click <a href=\"main_login.php\">here</a></h3></center></font>";
  }
 }
else
{
 echo $_SESSION["user"]." is already logged onto website.";
 }
?>

Or maybe like this:

PHP Code:

<?php
session_start();
if(empty($_SESSION["user"])&&empty($_SESSION["password"]))
{
 $_SESSION["user"] = empty($_POST['myusername']) ? "" : mysql_real_escape_string(stripslashes($_POST['myusername']));
 $_SESSION["password"] = empty($_POST['mypassword']) ? "" : mysql_real_escape_string(stripslashes($_POST['mypassword']));
 include 'dbc.php';
 $tbl_name="members";
 mysql_connect("$host", "$username", "$password")or die("cannot connect");
 mysql_select_db("$db_name")or die("cannot select DB");
 $sql="SELECT * FROM $tbl_name WHERE username='".$_SESSION["user"]."' and password='".$_SESSION["password"]."'";
 $result=mysql_query($sql);
 if($row = mysql_fetch_array($result))
 {
  if($row['mem_type'] == 'Student')
  {
   $_SESSION["student"] = "location:login_success.php";
   }
  elseif($row['mem_type'] == 'Teacher')
  {
   $_SESSION["teacher"] = "location:controlpanel.php";
   }
  }
 else
 {
  echo "<font color=#005B99><font face=Calibri><center><h2>Wrong Username or Password </h2><br/>";
  echo "<h3>To re-enter username and password click <a href=\"main_login.php\">here</a></h3></center></font>";
  }
 }
if(!empty($_SESSION["student"])){header($_SESSION["student"]);exit;}
elseif(!empty($_SESSION["teacher"])){header($_SESSION["teacher"]);exit;}
else{echo "You do not have permission to access this page";exit;}
?>

[landing]

Can I ask why you want to do this? (just for my own curiosity)

I've never really had a problem with this. If the site is well designed then it won't do any harm having multiple logins. Admittedly there's few reasons why a user should be logged in several times though...

[x70sef]

i want it so a user cannot log into the website twice at the same time under the same username and password

[landing]

Yeah, but why? What difference would it make?

Don't take that the wrong way. I'm just curious.

[x70sef]

i want it so a user cannot log into the website twice at the same time under the same username and password

[landing]

oh never mind.

[x70sef]

im not taking it the wrong way.. it makes the website much more secure