io.getlime.security.powerauth.lib.util.http.PowerAuthRequestCanonizationUtils Maven / Gradle / Ivy

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PowerAuth 2.0 utility module for HTTP support

There is a newer version: 1.9.0

package io.getlime.security.powerauth.lib.util.http;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class PowerAuthRequestCanonizationUtils {
	
	/**
	 * Utility variable, used for the purpose of GET query attribute sorting (query attribute key).
	 */
	private static final String KEY = "key";
	
	/**
	 * Utility variable, used for the purpose of GET query attribute sorting (query attribute value).
	 */
	private static final String VAL = "val";
	
	/**
	 * Take the GET request query string (for example, "param1=key1¶m2=key2") and convert it to the
	 * canonized form by sorting the key value pairs primarily by keys and by values in case the keys are
	 * equal.
	 * @param queryString The original get query string, obtained for example by 'request.getQueryString();'. 
	 * @return Canonized query string.
	 * @throws UnsupportedEncodingException In case UTF-8 is not supported.
	 */
	public static String canonizeGetParameters(String queryString) throws UnsupportedEncodingException {
		List> items = new ArrayList<>();
		String[] keyValuePairs = queryString.split("&"); // ... get the key value pairs
		for (String keyValue : keyValuePairs) {
			String[] tmp = keyValue.split("=", 1);
			if (tmp.length != 2) { // ... skip invalid values (this will likely fail signature verification)
				continue;
			}
			String key = URLDecoder.decode(tmp[0], "UTF-8"); // decoded GET query attribute key
			String val = URLDecoder.decode(tmp[1], "UTF-8"); // decoded GET query attribute value
			Map pair = new HashMap<>();
			pair.put(KEY, key);
			pair.put(VAL, val);
			items.add(pair);
		}
		
		// Sort the query key pair collection
		Collections.sort(items, new Comparator>() {
			@Override
			public int compare(Map left, Map right) {
				String leftKey = left.get(KEY);
				String leftVal = left.get(VAL);
				String rightKey = right.get(KEY);
				String rightVal = right.get(VAL);
				if (leftKey != null && leftKey.equals(rightKey)) {
					return leftVal != null ? leftVal.compareTo(rightVal) : -1;
				} else {
					return leftKey != null ? leftKey.compareTo(rightKey) : -1;
				}
			}
		});
		
		// Serialize the sorted items back to the signature base string
		String signatureBaseString = "";
		boolean firstSkipped = false;
		for (Map pair : items) {
			String key = pair.get(KEY);
			String val = pair.get(VAL);
			if (firstSkipped) { // ... for all items except for the first one, prepend "&"
				signatureBaseString += "&";
			} else {
				firstSkipped = true;
			}
			signatureBaseString += URLEncoder.encode(key, "UTF-8");
			signatureBaseString += "=";
			signatureBaseString += URLEncoder.encode(val, "UTF-8");
		}
		
		return signatureBaseString.length() > 0 ? signatureBaseString : null;
	}

}