Login and Logout using Sessions and Cookies

This is a very simple code and hardly requires any explanations. If you need any put the post here.

functions.php

PHP:

<?php

function createsessions($username,$password)
{
    //Add additional member to Session array as per requirement
    session_register();

    $_SESSION["gdusername"] = $username;
    $_SESSION["gdpassword"] = md5($password);
 
    if(isset($_POST['remme']))
    {
        //Add additional member to cookie array as per requirement
        setcookie("gdusername", $_SESSION['gdusername'], time()+60*60*24*100, "/");
        setcookie("gdpassword", $_SESSION['gdpassword'], time()+60*60*24*100, "/");
        return;
    }
}

function clearsessionscookies()
{
    unset($_SESSION['gdusername']);
    unset($_SESSION['gdpassword']);
 
    session_unset();
    session_destroy();

    setcookie ("gdusername", "",time()-60*60*24*100, "/");
    setcookie ("gdpassword", "",time()-60*60*24*100, "/");
}

function confirmUser($username,$password)
{
    // $md5pass = md5($password); // Not needed any more as pointed by ted_chou12

    /* Validate from the database but as for now just demo username and password */
    if($username == "demo" && $password = "demo")
        return true;
    else
        return false;
}

function checkLoggedin()
{
    if(isset($_SESSION['gdusername']) AND isset($_SESSION['gdpassword']))
        return true;
    elseif(isset($_COOKIE['gdusername']) && isset($_COOKIE['gdpassword']))
    {
        if(confirmUser($_COOKIE['gdusername'],$_COOKIE['gdpassword']))
        {
            createsessions($_COOKIE['gdusername'],$_COOKIE['gdpassword']);
            return true;
        }
        else
        {
            clearsessionscookies();
            return false;
        }
    }
    else
        return false;
}
?>


index.php

PHP:

<?php
ob_start();
session_start();

require_once ("functions.php");

if (checkLoggedin())
    echo "<H1>You are already logged in - <A href = \"login.php?do=logout\">logout</A></h1>";
else
    echo "<H1>You are not logged in - <A href = \"login.php\">login</A></h1></h1>";
?>

login.php

PHP:

<?php

ob_start();
session_start();

require_once ("functions.php");

$returnurl = urlencode(isset($_GET["returnurl"])?$_GET["returnurl"]:"");
if($returnurl == "")
    $returnurl = urlencode(isset($_POST["returnurl"])?$_POST["returnurl"]:"");

$do = isset($_GET["do"])?$_GET["do"]:"";

$do = strtolower($do);

switch($do)
{
case "":
    if (checkLoggedin())
    {
        echo "<H1>You are already logged in - <A href = \"login.php?do=logout\">logout</A></h1>";
    }
    else
    {
        ?>
        <form NAME="login1" ACTION="login.php?do=login" METHOD="POST" ONSUBMIT="return aValidator();">
        <input TYPE="hidden" name="returnurl" value="<?=$returnurl?>">
        <TABLE cellspacing="3">
        <TR>
            <TD>Username:</TD>
            <TD><input TYPE="TEXT" NAME="username"></TD>
            <TD>Password:</TD>
            <TD><input TYPE="PASSWORD" NAME="password"></TD>
        </TR>
        <TR>
            <TD colspan="4" ALIGN="center"><input TYPE="CHECKBOX" NAME="remme">&nbsp;Remember me for the next time I visit</TD>
        </TR>
        <TR>
            <TD ALIGN="CENTER" COLSPAN="4"><input TYPE="SUBMIT" name="submit" value="Login"></TD>
        </TR>
        </TABLE>
        </form>
    <?php
    }
    break;
case "login":
    $username = isset($_POST["username"])?$_POST["username"]:"";
    $password = isset($_POST["password"])?$_POST["password"]:"";

    if ($username=="" or $password=="" )
    {
        echo "<h1>Username or password is blank</h1>";
        clearsessionscookies();
        header("location: login.php?returnurl=$returnurl");
    }
    else
    {
        if(confirmuser($username,md5($password))) // As pointed out by asgard2005
        {
            createsessions($username,$password);
            if ($returnurl<>"")
                header("location: $returnurl");
            else
            {
                header("Location: index.php");
            }
        }
        else
        {
            echo "<h1>Invalid Username and/Or password</h1>";
            clearsessionscookies();
            header("location: login.php?returnurl=$returnurl");
        }
    }
    break;
case "logout":
    clearsessionscookies();
    header("location: index.php");
    break;
}
?>

Attachment also modified with a bug as pointed out by asgard2005 here

 

Sure. Just put your queries related to PHP in PHP forum and we will definitely help you master in PHP

 

For that probably you need to be clearing the cache because thats not the actual page but the cache version and applying some metas can even prevent that.