Added RegistryUpdater to broadcast server data to registries.

registry/src/main/java/nl/andrewl/aos2registryapi/ServerRegistry.java

@@ -73,7 +73,6 @@ public class ServerRegistry {
 
 	@Scheduled(fixedRate = 1, timeUnit = TimeUnit.MINUTES, initialDelay = 1)
 	public void purgeOldServers() {
-		log.info("Purging old servers.");
 		Queue<ServerIdentifier> removalQueue = new LinkedList<>();
 		final Instant cutoff = Instant.now().minus(SERVER_TIMEOUT);
 		for (var entry : servers.entrySet()) {

server/pom.xml

@@ -33,6 +33,12 @@
             <artifactId>jansi</artifactId>
             <version>2.4.0</version>
         </dependency>
+        <!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>2.9.1</version>
+        </dependency>
     </dependencies>
 
     <build>

server/src/main/java/nl/andrewl/aos2_server/ClientCommunicationHandler.java

@@ -107,6 +107,11 @@ public class ClientCommunicationHandler {
 						socket.close();
 						return;
 					}
+					if (server.getPlayerManager().getPlayers().size() >= server.getConfig().maxPlayers) {
+						Net.write(new ConnectRejectMessage("Server is full."), out);
+						socket.close();
+						return;
+					}
 
 					// Try to set the TCP timeout back to 0 now that we've got the correct request.
 					socket.setSoTimeout(0);

server/src/main/java/nl/andrewl/aos2_server/RegistryUpdater.java

@@ -0,0 +1,59 @@
+package nl.andrewl.aos2_server;
+
+import com.google.gson.Gson;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Component that sends regular updates to any configured server registries.
+ */
+public class RegistryUpdater {
+	private final Server server;
+	private final HttpClient httpClient;
+
+	public RegistryUpdater(Server server) {
+		this.server = server;
+		this.httpClient = HttpClient.newBuilder()
+				.connectTimeout(Duration.ofSeconds(3))
+				.build();
+	}
+
+	public void sendUpdates() {
+		var cfg = server.getConfig();
+		if (
+				cfg.registries != null &&
+				cfg.registries.length > 0 &&
+				cfg.name != null && !cfg.name.isBlank()
+		) {
+			Map<String, Object> data = new HashMap<>();
+			data.put("port", cfg.port);
+			data.put("name", cfg.name);
+			data.put("description", cfg.description);
+			data.put("maxPlayers", cfg.maxPlayers);
+			data.put("currentPlayers", server.getPlayerManager().getPlayers().size());
+			String json = new Gson().toJson(data);
+			for (String registryUrl : server.getConfig().registries) {
+				HttpRequest req = HttpRequest.newBuilder(URI.create(registryUrl + "/servers"))
+						.POST(HttpRequest.BodyPublishers.ofString(json))
+						.header("Content-Type", "application/json")
+						.timeout(Duration.ofSeconds(3))
+						.build();
+				try {
+					var resp = httpClient.send(req, HttpResponse.BodyHandlers.ofString());
+					if (resp.statusCode() != 200) {
+						System.err.println("Error response when sending registry update to " + registryUrl + ": " + resp.statusCode() + " " + resp.body());
+					}
+				} catch (IOException | InterruptedException e) {
+					System.err.println("An error occurred while sending registry update to " + registryUrl + ": " + e.getMessage());
+				}
+			}
+		}
+	}
+}

server/src/main/java/nl/andrewl/aos2_server/Server.java

@@ -24,7 +24,10 @@ import java.net.*;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.List;
+import java.util.concurrent.Executors;
 import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
 
 /**
  * The central server, which mainly contains all the different managers and
@@ -83,11 +86,15 @@ public class Server implements Runnable {
 		running = true;
 		new Thread(new UdpReceiver(datagramSocket, this::handleUdpMessage)).start();
 		new Thread(worldUpdater).start();
+		ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
+		var registryUpdater = new RegistryUpdater(this);
+		executorService.scheduleAtFixedRate(registryUpdater::sendUpdates, 0, 90, TimeUnit.SECONDS);
 		System.out.printf("Started AoS2 Server on TCP/UDP port %d; now accepting connections.%n", serverSocket.getLocalPort());
 		while (running) {
 			acceptClientConnection();
 		}
 		System.out.println("Shutting down the server.");
+		executorService.shutdown();
 		playerManager.deregisterAll();
 		worldUpdater.shutdown();
 		datagramSocket.close(); // Shuts down the UdpReceiver.

server/src/main/java/nl/andrewl/aos2_server/config/ServerConfig.java

@@ -2,6 +2,11 @@ package nl.andrewl.aos2_server.config;
 
 public class ServerConfig {
 	public int port = 25565;
+	public String name = "My Server";
+	public String description = "My server";
+	public String[] registries = new String[0];
+
+	public int maxPlayers = 32;
 	public int connectionBacklog = 5;
 	public float ticksPerSecond = 20.0f;
 	public String world = "worlds.redfort";

server/src/main/resources/default-config.yaml

@@ -1,5 +1,10 @@
 # Ace of Shades 2 Server Configuration
 port: 25565
+name: My Server
+description: This is my Ace of Shades server.
+registries:
+  - https://reg.aos2.net
+maxPlayers: 32
 connectionBacklog: 5
 ticksPerSecond: 20.0
 world: worlds.redfort