Undefined Array in "login_attempts"-CodePudding

Im trying to set a limited number of unlock/login attempts for my web app. Here is my code:

<?PHP
session_start();

if (isset($_SESSION["locked"])) {
    $difference = time() - $_SESSION["locked"];
    if ($difference > 10) {
        unset($_SESSION["locked"]);
        unset($_SESSION["login_attempts"]);
    }
}

if (isset($_POST["user"]) && !isset($_SESSION["user"])) {
    $users = ["admin" => "123456",];
 
    if (isset($users[$_POST["user"]])) {
        if ($users[$_POST["user"]] == $_POST["password"]) {
            $_SESSION["user"] = $_POST["user"];
        }
    }

    if (!isset($_SESSION["user"])) { 
        if (empty ($_POST["user"]) || empty ($_POST['password'])) {  
            $userErr= '<div  role="alert">
                    MISSING INPUT! Please make sure to input both username and password.</div>';  
            $failed = true;     
        } else {  

            $_SESSION["login_attempts"]  = 1;
            $_SESSION["error"] = "It doesn't match!";

            $userErr= '<div  role="alert">
                    INVALID CREDENTIALS! Entered username and password doesnt match any user accounts.</div>';  
            $failed = true; 
        }  
    }
}

if (isset($_SESSION["user"])) {
    header("Location: index.php");
    exit();
}
?>

<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial- 
    scale=1.0">
<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-1BmE4kWBq78iYhFldvKuhfTAU6auU8tT94WrHftjDbrCEXSU1oBoqyl2QvZ6jIW3" crossorigin="anonymous">
<title>Unlock Message</title>
<style>
    body{
        background-color: #85FFBD;
        background-image: linear-gradient(45deg, #85FFBD 0%, 
#FFFB7D 100%);
        background-size: cover;
        display: grid;
        align-items: center;
        justify-content: center;
        height: 100vh;
    }
    .container{
        width: 35rem;
        height: 25rem;
        box-shadow: 0 0 1rem 0 rgba(0, 0, 0, .2); 
        border-radius: 20px;
        background-color: rgba(255, 255, 255, .15);
        backdrop-filter: blur(20px);
    }
</style>
</head>
<body>

<?PHP
   if (isset($failed)) {
   echo $userErr;
   }
?>

<div  >
<h3 >Unlock Quote of the Day!</h3>
<p>In order to view the quote, please enter the user credentials.</p>
   <div >

<?php 
    if(isset($_SESSION["error"])) { 
?>
        <p style="color: red;"><?=$_SESSION["error"]; ?></p>
<?php 
        unset($_SESSION["error"]); } 
?>

    <form id="login-form" method="post" target="_self">
        <div >
            <label for="user" >Username</label>
            <input type="text"  name="user" value="admin">
    </div>
    <div >
        <label for="password" >Password</label>
        <input type="password"  name="password" value="123456">
    </div>
    
    <!-- <button type="submit"  value="Sign In" >Unlock</button> -->

<?php
    **if ($_SESSION["login_attempts"]> 2)**
    {
        $_SESSION["locked"] = time();
        echo "Please wait for 10 seconds";
    }
    else
    {
     
    ?>
        <button type="submit"  value="login_attempts">Unlock</button>
     
    <?php
     
    }
     
    ?>
    </form>
</div>

However, I am returning the error:

Warning: Undefined array key "login_attempts" in C:\xampp\htdocs\login.php on line 114 (I turned this line bold to see)

How can I fix this? I feel like I should define login_attempts but how? Thank you!

CodePudding user response：

Try this next line to $users = [...]

if (! isset ($_SESSION["login_attempts"])) {
   $_SESSION["login_attempts"] = 0;
}