What are the best practices for handling user input in PHP to prevent vulnerabilities and errors?

User input in PHP should always be sanitized and validated to prevent vulnerabilities such as SQL injection, cross-site scripting (XSS), and other types of attacks. One way to handle user input securely is to use functions like `filter_input()` and `htmlspecialchars()` to sanitize and validate input data before using it in your application. 

// Sanitize and validate user input using filter_input()
$username = filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING);
$email = filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL);

// Sanitize user input to prevent XSS attacks
$comment = htmlspecialchars($_POST['comment']);

// Use prepared statements to prevent SQL injection
$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");
$stmt->bindParam(':username', $username);
$stmt->execute();

Keywords

input validation data sanitization SQL injection cross-site scripting error handling

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