What are the steps for validating and sanitizing user input data in PHP to prevent security vulnerabilities like SQL injections?

To prevent security vulnerabilities like SQL injections, it is crucial to validate and sanitize user input data in PHP. This can be done by using functions like filter_var() to validate input data and functions like mysqli_real_escape_string() to sanitize input data before using it in SQL queries. 

// Validate input data
$username = filter_var($_POST['username'], FILTER_SANITIZE_STRING);
$email = filter_var($_POST['email'], FILTER_VALIDATE_EMAIL);

// Sanitize input data
$username = mysqli_real_escape_string($conn, $username);
$email = mysqli_real_escape_string($conn, $email);

// Use the sanitized input data in SQL queries
$query = "INSERT INTO users (username, email) VALUES ('$username', '$email')";
mysqli_query($conn, $query);

Keywords

Validation Sanitization User Input Security Vulnerabilities SQL Injection

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