accesso utente

[imperor]

accesso utente

salve non riesco a capire perchè se un utente non registrato prova a effettuare l'accesso da pagina bianca come posso risolvere? chiedo aiuto posto i codici

<form method="post" 
			action="app/http/auth.php">
            <div class="d-flex
			justify-content-center
			align-items-center
			flex-column">
			<h3 class="display-4 fs-1 
			text-center">
			</h3>   

			</div>
			<?php if (isset($_GET['error'])) { ?>
			<div class="alert alert-warning" role="alert">
			<?php echo htmlspecialchars($_GET['error']);?>
			</div>
			<?php } ?>
										
			<?php if (isset($_GET['success'])) { ?>
			<div class="alert alert-success" role="alert">
			<?php echo htmlspecialchars($_GET['success']);?>
			</div>
			<?php } ?>
			<div class="mb-3">
			<label class="form-label">
			Nome utente</label>
			<input type="text" 
			class="form-login"
			name="username">
			</div>

			<div class="mb-3">
			<label class="form-label">
			Password</label>
			<input type="password" 
			class="form-login"
			name="password">
			</div>
									  
			 <button type="submit" 
			 class="btn btn-outline-secondary">
			 Accedi</button>
			 <a class="btn btn-outline-secondary" href="signup.php" role="button">Registrati</a>
			 <hr>
			 <br>
			 <a class="btn btn-outline-secondary" href="recupero.php" role="button">Password dimenticata?</a>
			 </form>  
----------------------------------------------

<?php  
session_start();

# check if username & password  submitted
if(isset($_POST['username']) &&
   isset($_POST['password'])){

   # database connection file
   include '../db.conn.php';
   
   # get data from POST request and store them in var
   $password = $_POST['password'];
   $username = $_POST['username'];
   
   $data = "username=".$username;
   
   #simple form Validation
   if(empty($username)){
      # error message
      $em = "inserisci il nome utente";

      # redirect to 'index.php' and passing error message
      header("Location: ../../index.php?error=$em&$data");
   }else if(empty($password)){
      # error message
      $em = "inserisci la password";

      # redirect to 'index.php' and passing error message
      header("Location: ../../index.php?error=$em&$data");
   }else {
      $sql  = "SELECT * FROM 
               users WHERE username=?";
      $stmt = $conn->prepare($sql);
      $stmt->execute([$username]);

      # if the username is exist
      if($stmt->rowCount() === 1){
        # fetching user data
        $user = $stmt->fetch();
		
        # if both username's are strictly equal
        if ($user['username'] === $username) {
           
           # verifying the encrypted password
          if (password_verify($password, $user['password'])) {
			  

            # successfully logged in
            # creating the SESSION
            $_SESSION['username'] = $user['username'];
            $_SESSION['name'] = $user['name'];
            $_SESSION['user_id'] = $user['user_id'];

            # redirect to 'home.php'
            header("Location: ../../home.php");

          }else {
            # error message
            $em = "Nome utente o password errati";

            # redirect to 'index.php' and passing error message
            header("Location: ../../index.php?error=$em&$data");
          }
        }else {
          # error message
          $em = "Nome utente o password errati";

          # redirect to 'index.php' and passing error message
          header("Location: ../../index.php?error=$em&$data");
        }
      }
   }
}else {
  header("Location: ../../index.php");
  exit;
}

[imperor]

Buongiorno sono riuscito a risolvere certo non è un gran che ma va bene e funziona posto il codice

<?php
    session_start();
    include('../db.conn.php');
    if (isset($_POST['username'])) {
        $username = $_POST['username'];
        $password = $_POST['password'];
        $query = $conn->prepare("SELECT * FROM users WHERE username=:username");
        $query->bindParam("username", $username, PDO::PARAM_STR);
        $query->execute();
        $result = $query->fetch(PDO::FETCH_ASSOC);
        if (!$result) {
           
		$em = "Il nome utente non risulta registrato!";
    	header("Location: ../../index.php?error=$em");
			
        } else {
            if (password_verify($password, $result['password'])) {
                $_SESSION['user_id'] = $result['user_id'];
				$_SESSION['username'] = $result['username'];
				$_SESSION['name'] = $result['name'];
				
				header("Location: ../../home.php");
				
                echo '<p class="success">Accesso eseguito con successo!</p>';
            } else {
                $em = "Nome utente o password errata!";
    	    header("Location: ../../index.php?error=$em");
            }
        }
    }
?>