import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class ApiPayloadSanitizer {

/**

* Sanitizes an API payload string by removing potentially harmful characters and patterns.

* This is a basic sanitization for isolated environments. More robust sanitization may be needed for production.

* @param payload The input API payload string.

* @return The sanitized payload string.

*/

public static String sanitizePayload(String payload) {

if (payload == null) {

return ""; // Handle null input gracefully

}

// Remove HTML tags

String sanitized = removeHtmlTags(payload);

// Remove script tags

sanitized = removeScriptTags(sanitized);

// Remove potentially harmful characters (e.g., control characters)

sanitized = removeControlCharacters(sanitized);

// Remove extra whitespace

sanitized = sanitizeWhitespace(sanitized);

return sanitized;

}

private static String removeHtmlTags(String payload) {

// Regex to remove HTML tags

Pattern pattern = Pattern.compile("<[^>]*>");

Matcher matcher = pattern.matcher(payload);

return matcher.replaceAll("");

}

private static String removeScriptTags(String payload) {

// Regex to remove script tags

Pattern pattern = Pattern.compile("<script.*?>.*?</script>");

Matcher matcher = pattern.matcher(payload);

return matcher.replaceAll("");

}

private static String removeControlCharacters(String payload) {

// Remove control characters (ASCII 0-31)

return payload.replaceAll("[\\x00-\\x1F]", "");

}

private static String sanitizeWhitespace(String payload) {

//Replace multiple spaces with single space and trim leading/trailing spaces.

return payload.replaceAll("\\s+", " ").trim();

}

public static void main(String[] args) {

String testPayload = "<p>This is <b>test</b> payload with <script>alert('XSS')</script> some <binary data, 1 bytes><</binary> control characters.</p>";

String sanitizedPayload = sanitizePayload(testPayload);

System.out.println("Original Payload: " + testPayload);

System.out.println("Sanitized Payload: " + sanitizedPayload);

}

}