PHP - Login / Logout Links

I based this off some other pages read, and think I'm doing this wrong or it's just not connecting. 

Code: [Select]
Here's the database table:
CREATE TABLE users (
    id INT NOT NULL AUTO_INCREMENT,
    username VARCHAR(30) NOT NULL UNIQUE,
    password VARCHAR(64) NOT NULL,
    salt VARCHAR(3) NOT NULL,
    PRIMARY KEY(id)
);


Ando far I have index.php with my login form <form name="login" action="login.php" method="post">
    Username: <input type="text" name="username" />
    Password: <input type="password" name="password" />
    <input type="submit" value="Login" />
</form><br />Would you like to <a href="register.php">register?</a></center>

Then I have my actual login on login.php (header.php includes website's main image as well as session_start():
<?php

include('header.php');

$username = $_POST['username'];
$password = $_POST['password'];
//connect to the database here
$username = mysql_real_escape_string($username);
$query = "SELECT password, salt
        FROM users
        WHERE username = '$username';";
$result = mysql_query($query);
if(mysql_num_rows($result) < 1) //no such user exists
{
    header('Location: login.php');
    die();
}
$userData = mysql_fetch_array($result, MYSQL_ASSOC);
$hash = hash('sha256', $userData['salt'] . hash('sha256', $password) );
if($hash != $userData['password']) //incorrect password
{
    header('Location: login_form.php');
    die();
}
else
{
    validateUser(); //sets the session data for this user
}
//redirect to another page or display "login success" message
?>

then I have my register php on register.php:
<?php

include('header.php');

//retrieve our data from POST
$username = $_POST['username'];
$pass1 = $_POST['pass1'];
$pass2 = $_POST['pass2'];
if($pass1 != $pass2)
    header('Location: register_form.php');
if(strlen($username) > 30)
    header('Location: register_form.php');
    
    $hash = hash('sha256', $pass1);
    function createSalt()
{
    $string = md5(uniqid(rand(), true));
    return substr($string, 0, 3);
}
$salt = createSalt();
$hash = hash('sha256', $salt . $hash);

$dbhost = 'localhost';
$dbname = 'mygame';
$dbuser = 'root';
$dbpass = '';
$conn = mysql_connect($dbhost, $dbuser, $dbpass);
mysql_select_db($dbname, $conn);
//sanitize username
$username = mysql_real_escape_string($username);
$query = "INSERT INTO users ( username, password, salt )
        VALUES ( '$username' , '$hash' , '$salt' );";
mysql_query($query);
mysql_close();
header('Location: login.php');

?>
and lastly the register form:
   
    <center><form name="register" action="register.php" method="post">
    Username: <input type="text" name="username" maxlength="30" />
    Password: <input type="password" name="pass1" />
    Password Again: <input type="password" name="pass2" />
    <input type="submit" value="Register" />
</form></center>
I am getting the errors:
Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in /Applications/XAMPP/xamppfiles/htdocs/testing/login.php on line 13

Warning: Cannot modify header information - headers already sent by (output started at /Applications/XAMPP/xamppfiles/htdocs/testing/config.php:1) in /Applications/XAMPP/xamppfiles/htdocs/testing/login.php on line 15

Could someone explain why this is happening?

Hi,

I am having a bit of problem with my login/logout script. When user is logged in I want the script to show logout and if they are not login I want the script to show login. The problem is even when the user is logged in it says "you must be logged in Click here to login " here is the script Please help

Code: [Select]


<?php
session_start();
$_SESSION['username'] = $_POST['username'];
if ($_SESSION['username'])
echo "Welcome, ".$_SESSION['username']."!<br><a href='logout.php'>Logout</a>" ;
else
 die("you must be logged in <a href='Login.php'>Click here to login</a>");
?>


what did I do wrong in this script ?
Thanks

This topic has been moved to Application Design.

http://www.phpfreaks.com/forums/index.php?topic=313919.0

I am having problems understanding the reason for why the user has to click logout twice, here's the bulk of the code:

<?php
ini_set('display_errors',0);

require_once 'header.html';

require_once 'db.functions.php';

require_once 'config.php';

$database = dbConnect($host, $username, $password, $database); // should output 1 or nothing at all!

if($database == true)
{

// now connected?

// carry on with logic of outputting the blog contents:

$result = entries("SELECT * FROM entries");

printf("<table>");

while($row = mysql_fetch_array($result))

{

printf("

<tr>

<td>%s</td>

<td>%s</td>

</tr>

<tr>

<td colspan=\"2\">%s</td>

</tr>

", $row[2], $row[4], $row[3]);

}

printf("</table>");

printf("\n\n");

session_name("jeremysmith_blog");

session_start();

if(array_key_exists('login',$_SESSION))

{

if($_SESSION['login'] == 1) // change this to correspond with session on the login.php script

{

printf("<p>Welcome %s</p>

<p>To logout, click <a href=\"index.php?action=logout\">here</a></p>

",$_SESSION['username']);

}

} else {

printf("<p>You are not logged in, please click <a href=\"login.php\">here</a> to login.</p>");

}

} else {

printf("\n<p id=\"error\">Could not connect to database, please try again later.</p>");

}

// init the logout script?
if(array_key_exists('action',$_GET))
{

if($_GET['action'] == 'logout')

{

// log user out of the system:

unset($_SESSION['login']);

unset($_SESSION['username']);

session_destroy();

}
}


printf("\n"); // just for output format!
require_once 'footer.html';

Why does the user have to click logout twice, have I missed anything?

Any helps appreciated thanks.

this is not working

Code: [Select]
<?php

session_start();
$username = $_SESSION['username'];
echo mysql_query("UPDATE members SET online='0' WHERE username='$username' AND online='1'");
session_destroy();

echo "You've been logged out. <a href='index.php'>Click here</a> to return.";

?>
what im trying to do is change the online mysql data from 1 back to 0 as i want to show when a user is on and off line

can anyone help