What are common pitfalls when handling form data in PHP, specifically in relation to $_POST and $_SESSION variables?

One common pitfall when handling form data in PHP is not properly sanitizing and validating input from $_POST variables, which can lead to security vulnerabilities such as SQL injection or cross-site scripting attacks. To mitigate this, always sanitize and validate user input before using it in your application. 

// Example of sanitizing and validating form data from $_POST variables
$username = isset($_POST['username']) ? htmlspecialchars(trim($_POST['username'])) : '';
$password = isset($_POST['password']) ? trim($_POST['password']) : '';

// Validate input
if(empty($username) || empty($password)) {
    // Handle validation error
}

// Sanitize input
$username = filter_var($username, FILTER_SANITIZE_STRING);
$password = filter_var($password, FILTER_SANITIZE_STRING);

// Now you can safely use $username and $password in your application

Keywords

$_POST $_SESSION form data handling pitfalls

Related Questions