What are some best practices for writing secure PHP code?

One best practice for writing secure PHP code is to validate and sanitize user input to prevent SQL injection and cross-site scripting attacks. This can be done by using functions like mysqli_real_escape_string() and htmlspecialchars() before using user input in database queries or outputting it to the browser. 

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

// Validate and sanitize user input
$clean_input = mysqli_real_escape_string($connection, $user_input);
$clean_input = htmlspecialchars($clean_input);

// Use the sanitized input in database query
$query = "INSERT INTO users (name) VALUES ('$clean_input')";
mysqli_query($connection, $query);

// Output the sanitized input to the browser
echo "Hello, " . $clean_input;

Keywords

SQL injection cross-site scripting password hashing input validation secure file handling

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