How can I securely handle user input in PHP?

When handling user input in PHP, it is important to sanitize and validate the input to prevent security vulnerabilities such as SQL injection and cross-site scripting attacks. One way to securely handle user input is to use functions like htmlspecialchars() to escape special characters and filter_var() to validate input against a specific filter. 

// Sanitize user input using htmlspecialchars()
$userInput = htmlspecialchars($_POST['user_input']);

// Validate user input using filter_var()
if (filter_var($userInput, FILTER_VALIDATE_EMAIL)) {
    // Input is a valid email address
} else {
    // Input is not a valid email address
}

Keywords

filter_input htmlspecialchars prepared statements validation CSRF protection

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