PHP: Display data of logged on person

[SpyJoe]

Hi everyone, I'm creating a social network website, like MySpace or Facebook, but a simple one. I used a code I found on a website for login, register and logout. What I'm trying to do now is display member's data (like name, gender, etc) that member has registered with. So just like a profile of someone who is logged in.

This is part of the code that I have already:

<?
$conn = mysql_connect("###", "###", "###") or die(mysql_error());
mysql_select_db('###', $conn) or die(mysql_error());

$result = mysql_query("SELECT * FROM users",$conn);
printf("First Name: %s<br>\n", mysql_result($result,0,"firstname"));
printf("Last Name: %s<br>\n", mysql_result($result,0,"lastname"));
printf("Gender: %s<br>\n", mysql_result($result,0,"gender"));
mysql_close($conn);
?>

But this only displays the first row from my database. I need to do something like this:

$result = mysql_query("SELECT * FROM users WHERE username=$username",$conn);

I'm not sure if the username of person who is logged in is stored in a cookie or somewhere else, because code is quite complicated.

What do I need to put, so that it displays information of a person who is logged in? Can someone reply asap plz. Thank you!

P.S. Sorry forgot the most important thing. This is where I got the code from:

http://www.evolt.org/article/comment/17/60265/index.html

[barts2108]

If you only want to show the username to the logged in user
you can add a session variable to his/her current session

if (login($_POST['username'],$_POST['password']) == TRUE)
{
	// User logged in. store username in session variables
	session_register("username");
	$_SESSION['username'] = $_POST['username'];
}

Anywhere you want to show the username you can echo it assuming
all your pages have .php extension

example:

<p><?php echo($_SESSION['username']); ?></p>

If you want to show to all users who's online, you must make sure that
active sessions will expire automatically within reasonable time.

Upon login of a user, in the login table you can have a column "loggedin"
and keep track of users who logged in or logged off. If a user not logs
off but the session expires, I am not sure how to handle the loggedin column,
but I hope it gives you an idea

[Alley Cat]

This is the code that I use to welcome a member to each page that they view.

if (!isset($_SESSION['first_name'])) {

	$url = 'http://' . $_SERVER['HTTP_HOST'] . dirname($_SERVER['PHP_SELF']);
	if ((substr($url, -1) == '/') OR (substr($url, -1) == '\\') ) {
		$url = substr ($url, 0, -1);
	}
	$url .= '/login.php';
	
	ob_end_clean();
	header("Location: $url");
	exit();
	
} else {
	};

echo '<h1>Welcome';
if (isset($_SESSION['first_name'])) {
	echo ", {$_SESSION['first_name']}!";
};
echo '</h1>';