What best practices should be followed when handling 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 common best practice is to use functions like htmlspecialchars() to escape special characters and prevent script injection. Additionally, input validation functions like filter_var() can be used to ensure that the input meets certain criteria, such as being a valid email address or numeric value. 

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

// Validate user input using filter_var()
if (filter_var($userInput, FILTER_VALIDATE_EMAIL)) {
    echo "Valid email address";
} else {
    echo "Invalid email address";
}

Keywords

filter_var htmlspecialchars prepared statements validation sanitization

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