What are some best practices for handling input validation and sanitization in PHP to prevent issues with user input?

Input validation and sanitization are crucial in preventing security vulnerabilities such as SQL injection and cross-site scripting attacks. To handle input validation in PHP, you should always validate user input against expected formats and ranges. Sanitization involves removing potentially harmful characters or escaping user input before using it in a query or output. 

// Example of input validation and sanitization in PHP
$user_input = $_POST['user_input'];

// Validate input
if (!filter_var($user_input, FILTER_VALIDATE_EMAIL)) {
    // Invalid email format
    // Handle error
}

// Sanitize input
$sanitized_input = filter_var($user_input, FILTER_SANITIZE_STRING);

// Use sanitized input in query or output
echo $sanitized_input;

Keywords

filter_var htmlspecialchars htmlentities validation sanitization

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