What are some best practices for handling user input validation in PHP scripts?

User input validation is crucial in PHP scripts to prevent security vulnerabilities such as SQL injection and cross-site scripting attacks. Best practices include sanitizing input data, validating input against expected formats, and using parameterized queries when interacting with databases. 

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

// Sanitize input data
$cleanInput = filter_var($userInput, FILTER_SANITIZE_STRING);

// Validate input against expected format
if (preg_match("/^[a-zA-Z0-9]+$/", $cleanInput)) {
    // Input is valid, proceed with processing
} else {
    // Input is invalid, handle error
}

Keywords

filter_var htmlspecialchars validation sanitize input validation

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