How can PHP developers securely handle user input data, such as $_GET parameters, to prevent manipulation and unauthorized access?

To securely handle user input data in PHP, developers should sanitize and validate all incoming data, especially $_GET parameters, to prevent manipulation and unauthorized access. This can be achieved by using functions like filter_input() or filter_var() to sanitize input data and validating it against expected formats or values. 

// Sanitize and validate user input from $_GET parameter
$user_id = filter_input(INPUT_GET, 'user_id', FILTER_VALIDATE_INT);

if($user_id === false) {
    // Invalid input, handle error
} else {
    // Proceed with sanitized and validated user_id
}

Keywords

filter_input htmlspecialchars prepared statements validation CSRF protection

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