What are some best practices for restricting font sizes and font types when parsing BB-Codes in PHP?

When parsing BB-Codes in PHP, it is important to restrict font sizes and font types to maintain consistency and prevent potential security vulnerabilities. One way to achieve this is by using regular expressions to validate and sanitize the input before processing it. By defining a whitelist of allowed font sizes and font types, you can ensure that only safe and acceptable values are used in the parsed output. 

// Define a whitelist of allowed font sizes and font types
$allowedFontSizes = ['small', 'medium', 'large'];
$allowedFontTypes = ['Arial', 'Verdana', 'Helvetica'];

// Parse BB-Codes and restrict font sizes and font types
$bbCode = "[font size='medium' color='red']Hello World[/font]";
$pattern = "/\[font size='(" . implode('|', $allowedFontSizes) . ")' color='(" . implode('|', $allowedFontTypes) . ")'\](.*?)\[\/font\]/";
$replacement = "<span style='font-size: $1; font-family: $2;'>$3</span>";
$parsedOutput = preg_replace($pattern, $replacement, $bbCode);

echo $parsedOutput;

Keywords

BB-Codes font sizes font types parsing restrictions

Related Questions