Simple SSDP Java Client

SSDP.java

import static java.nio.charset.StandardCharsets.*;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.SocketTimeoutException;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Consumer;

public class SSDP {

	public static final String MULTICAST_ADDRESS = "239.255.255.250";
	public static final int PORT = 1900;

	public static final String SERVICE_TYPE_ALL = "ssdp:all";
	public static final String SERVICE_TYPE_DLNA_MEDIA_SERVER = "urn:schemas-upnp-org:device:MediaServer:1";

	public static final int MAX_WAIT_TIME_SECONDS = 5;

	private static DatagramPacket createRequest(String address, int port, String serviceType, int maxWaitTimeSeconds) throws IOException {
		StringBuilder m = new StringBuilder("M-SEARCH * HTTP/1.1\r\n");
		m.append("HOST: " + address + ":" + port + "\r\n");
		m.append("MAN: \"ssdp:discover\"\r\n");
		m.append("MX: " + maxWaitTimeSeconds + "\r\n");
		m.append("ST: " + serviceType + "\r\n");
		m.append("\r\n");

		byte[] content = m.toString().getBytes(UTF_8);
		return new DatagramPacket(content, content.length, InetAddress.getByName(address), port);
	}

	private static Map<String, String> parseResponse(byte[] bytes) {
		Map<String, String> headers = new HashMap<String, String>();

		String response = new String(bytes, UTF_8);
		for (String line : response.split("\r\n")) {
			String[] header = line.split(": ", 2);
			if (header.length == 2) {
				headers.put(header[0], header[1]);
			}
		}

		return headers;
	}

	public static void discover(String serviceType, Consumer<Map<String, String>> handler) throws IOException {
		discover(MULTICAST_ADDRESS, PORT, serviceType, MAX_WAIT_TIME_SECONDS, handler);
	}

	public static void discover(String serviceType, int maxWaitTimeSeconds, Consumer<Map<String, String>> handler) throws IOException {
		discover(MULTICAST_ADDRESS, PORT, serviceType, maxWaitTimeSeconds, handler);
	}

	public static void discover(String address, int port, String serviceType, int maxWaitTimeSeconds, Consumer<Map<String, String>> handler) throws IOException {
		DatagramPacket request = createRequest(address, port, serviceType, maxWaitTimeSeconds);

		try (MulticastSocket multicastSocket = new MulticastSocket(request.getPort())) {
			multicastSocket.setSoTimeout(maxWaitTimeSeconds * 1000);
			multicastSocket.send(request);

			byte[] buffer = new byte[2048];
			DatagramPacket packet = new DatagramPacket(buffer, buffer.length);

			try {
				while (true) {
					multicastSocket.receive(packet);
					handler.accept(parseResponse(packet.getData()));
				}
			} catch (SocketTimeoutException e) {
				// ignore;
			}
		}
	}

}