What are some best practices for handling URL parameters in PHP?

When handling URL parameters in PHP, it is important to sanitize and validate the input to prevent security vulnerabilities such as SQL injection or cross-site scripting attacks. One best practice is to use PHP's filter_input() function to retrieve and sanitize URL parameters. Additionally, always validate the input against expected values to ensure data integrity. 

// Retrieve and sanitize URL parameter using filter_input()
$param = filter_input(INPUT_GET, 'param', FILTER_SANITIZE_STRING);

// Validate the input against expected values
$allowed_values = ['value1', 'value2', 'value3'];
if (!in_array($param, $allowed_values)) {
    // Handle invalid input
    echo "Invalid parameter value";
} else {
    // Process the parameter
    echo "Parameter: " . $param;
}

Keywords

URL parameters PHP security validation sanitization

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