What are the best practices for handling user input validation and sanitization in PHP applications?

User input validation and sanitization are essential in PHP applications to prevent security vulnerabilities such as SQL injection, cross-site scripting (XSS), and other forms of attacks. To handle user input validation, always validate and sanitize user input before using it in your application. Use PHP functions like filter_var() for validation and functions like htmlentities() or htmlspecialchars() for sanitization to prevent malicious input. 

// Example of validating and sanitizing user input in PHP
$userInput = $_POST['user_input'];

// Validate user input
if (filter_var($userInput, FILTER_VALIDATE_EMAIL)) {
    // Sanitize user input
    $sanitizedInput = htmlentities($userInput);

    // Use the sanitized input in your application
    echo "Sanitized input: " . $sanitizedInput;
} else {
    echo "Invalid input";
}

Keywords

filter_var htmlspecialchars validation sanitization input validation

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