What are the best practices for handling user input parameters like $_GET in PHP to ensure security and maintainability?

When handling user input parameters like $_GET in PHP, it is important to validate and sanitize the input to prevent security vulnerabilities such as SQL injection and cross-site scripting attacks. One way to do this is by using filter_input() function along with filter_var() function to validate and sanitize the input data. Additionally, it is recommended to use prepared statements when interacting with a database to prevent SQL injection attacks. 

// Validate and sanitize user input from $_GET
$user_id = filter_input(INPUT_GET, 'user_id', FILTER_VALIDATE_INT);

if ($user_id === false) {
    // Handle invalid input
    die("Invalid user ID");
}

// Use prepared statements to interact with the database
$stmt = $pdo->prepare("SELECT * FROM users WHERE id = :user_id");
$stmt->bindParam(':user_id', $user_id, PDO::PARAM_INT);
$stmt->execute();
$user = $stmt->fetch();

Keywords

input validation sanitization prepared statements cross-site scripting (XSS) data filtering

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