What are the key considerations for structuring PHP classes to ensure effective form validation and data sanitization?

When structuring PHP classes for form validation and data sanitization, it is important to separate concerns by creating separate classes or methods for validation and sanitization. This helps maintain a clean and organized codebase, making it easier to debug and maintain. Additionally, using PHP's built-in filter functions and validation libraries can help streamline the process and ensure secure data handling.

class FormValidator {
    public function validateForm($formData) {
        // Validation logic here
    }
}

class DataSanitizer {
    public function sanitizeData($data) {
        // Sanitization logic here
    }
}

// Implementation example
$formData = $_POST;

$validator = new FormValidator();
$sanitizer = new DataSanitizer();

$validatedData = $validator->validateForm($formData);
$sanitizedData = $sanitizer->sanitizeData($validatedData);

// Process sanitized data