Added catalog discovery server, readmes and improved some server channel logic.

catalog/README.md

@@ -0,0 +1,3 @@
+# Concord Catalog
+
+The catalog is an HTTP server that is used as a "discovery" server that connects clients to the concord servers they might want to join. Clients will request a list of servers from the catalog, and servers are responsible for regularly sending their metadata to any catalogs they wish to be publicly visible in.

catalog/pom.xml

@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>concord</artifactId>
+        <groupId>nl.andrewl</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>concord-catalog</artifactId>
+
+    <properties>
+        <maven.compiler.source>16</maven.compiler.source>
+        <maven.compiler.target>16</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.undertow</groupId>
+            <artifactId>undertow-core</artifactId>
+            <version>2.2.8.Final</version>
+        </dependency>
+        <dependency>
+            <groupId>io.undertow</groupId>
+            <artifactId>undertow-servlet</artifactId>
+            <version>2.2.8.Final</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.12.4</version>
+        </dependency>
+    </dependencies>
+</project>

catalog/src/main/java/module-info.java

@@ -0,0 +1,10 @@
+module concord_catalog {
+	requires com.fasterxml.jackson.databind;
+	requires undertow.core;
+	requires undertow.servlet;
+	requires java.servlet;
+	requires jdk.unsupported;
+
+	exports nl.andrewl.concord_catalog.servlet to undertow.servlet;
+	opens nl.andrewl.concord_catalog.servlet to com.fasterxml.jackson.databind;
+}

catalog/src/main/java/nl/andrewl/concord_catalog/CatalogServer.java

@@ -0,0 +1,65 @@
+package nl.andrewl.concord_catalog;
+
+import io.undertow.Undertow;
+import io.undertow.server.HttpHandler;
+import io.undertow.servlet.Servlets;
+import io.undertow.servlet.api.DeploymentInfo;
+import io.undertow.servlet.api.DeploymentManager;
+import nl.andrewl.concord_catalog.servlet.ServersServlet;
+
+import javax.servlet.ServletException;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Properties;
+
+public class CatalogServer {
+	private static final String SETTINGS_FILE = "concord-catalog.properties";
+
+	public static void main(String[] args) throws ServletException, IOException {
+		var props = loadProperties();
+		startServer(Integer.parseInt(props.getProperty("port")));
+	}
+
+	/**
+	 * Starts the Undertow HTTP servlet container.
+	 * @param port The port to bind to.
+	 * @throws ServletException If the server could not be started.
+	 */
+	private static void startServer(int port) throws ServletException {
+		System.out.println("Starting server on port " + port + ".");
+		DeploymentInfo servletBuilder = Servlets.deployment()
+				.setClassLoader(CatalogServer.class.getClassLoader())
+				.setContextPath("/")
+				.setDeploymentName("Concord Catalog")
+				.addServlets(
+						Servlets.servlet("ServersServlet", ServersServlet.class)
+								.addMapping("/servers")
+				);
+		DeploymentManager manager = Servlets.defaultContainer().addDeployment(servletBuilder);
+		manager.deploy();
+		HttpHandler servletHandler = manager.start();
+		Undertow server = Undertow.builder()
+				.addHttpListener(port, "0.0.0.0")
+				.setHandler(servletHandler)
+				.build();
+		server.start();
+	}
+
+	/**
+	 * Loads properties from all necessary locations.
+	 * @return The properties that were loaded.
+	 * @throws IOException If an error occurs while reading properties.
+	 */
+	private static Properties loadProperties() throws IOException {
+		Properties props = new Properties();
+		props.load(CatalogServer.class.getResourceAsStream("/nl/andrewl/concord_catalog/defaults.properties"));
+		Path settingsPath = Path.of(SETTINGS_FILE);
+		if (Files.exists(settingsPath)) {
+			props.load(Files.newBufferedReader(settingsPath));
+		} else {
+			System.out.println("Using built-in default settings. Create a concord-catalog.properties file to configure.");
+		}
+		return props;
+	}
+}

catalog/src/main/java/nl/andrewl/concord_catalog/servlet/Page.java

@@ -0,0 +1,57 @@
+package nl.andrewl.concord_catalog.servlet;
+
+import java.util.List;
+
+public class Page<T> {
+	private final List<T> contents;
+	private final int elementCount;
+	private final int pageSize;
+	private final int currentPage;
+	private final boolean firstPage;
+	private final boolean lastPage;
+	private final String order;
+	private final String orderDirection;
+
+	public Page(List<T> contents, int currentPage, int pageSize, String order, String orderDirection) {
+		this.contents = contents;
+		this.elementCount = contents.size();
+		this.pageSize = pageSize;
+		this.currentPage = currentPage;
+		this.firstPage = currentPage == 0;
+		this.lastPage = this.elementCount < this.pageSize;
+		this.order = order;
+		this.orderDirection = orderDirection;
+	}
+
+	public List<T> getContents() {
+		return contents;
+	}
+
+	public int getElementCount() {
+		return elementCount;
+	}
+
+	public int getPageSize() {
+		return pageSize;
+	}
+
+	public int getCurrentPage() {
+		return currentPage;
+	}
+
+	public boolean isFirstPage() {
+		return firstPage;
+	}
+
+	public boolean isLastPage() {
+		return lastPage;
+	}
+
+	public String getOrder() {
+		return order;
+	}
+
+	public String getOrderDirection() {
+		return orderDirection;
+	}
+}

catalog/src/main/java/nl/andrewl/concord_catalog/servlet/ServerMetaData.java

@@ -0,0 +1,82 @@
+package nl.andrewl.concord_catalog.servlet;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+import java.util.Objects;
+
+public class ServerMetaData implements Comparable<ServerMetaData> {
+	private String name;
+	private String description;
+	private String host;
+	private int port;
+
+	@JsonIgnore
+	private long lastUpdatedAt;
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getDescription() {
+		return description;
+	}
+
+	public void setDescription(String description) {
+		this.description = description;
+	}
+
+	public String getHost() {
+		return host;
+	}
+
+	public void setHost(String host) {
+		this.host = host;
+	}
+
+	public int getPort() {
+		return port;
+	}
+
+	public void setPort(int port) {
+		this.port = port;
+	}
+
+	public String getAddress() {
+		return this.host + ":" + this.port;
+	}
+
+	public long getLastUpdatedAt() {
+		return lastUpdatedAt;
+	}
+
+	public void setLastUpdatedAt(long lastUpdatedAt) {
+		this.lastUpdatedAt = lastUpdatedAt;
+	}
+
+	@Override
+	public int compareTo(ServerMetaData o) {
+		int result = this.name.compareTo(o.getName());
+		if (result == 0) {
+			result = this.getAddress().compareTo(o.getAddress());
+		}
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (o.getClass().equals(this.getClass())) {
+			ServerMetaData other = (ServerMetaData) o;
+			return this.name.equals(other.getName()) && this.getAddress().equals(other.getAddress());
+		}
+		return false;
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash(getName(), getAddress());
+	}
+}

catalog/src/main/java/nl/andrewl/concord_catalog/servlet/ServersServlet.java

@@ -0,0 +1,57 @@
+package nl.andrewl.concord_catalog.servlet;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.Map;
+import java.util.SortedSet;
+import java.util.TreeSet;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * This servlet is the main HTTP endpoint for getting the list of servers and
+ * also uploading one's own server data.
+ */
+public class ServersServlet extends HttpServlet {
+	private static final SortedSet<ServerMetaData> servers = new TreeSet<>();
+	private static final ObjectMapper mapper = new ObjectMapper();
+	private static final ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
+	static {
+		executorService.scheduleAtFixedRate(() -> {
+			long now = System.currentTimeMillis();
+			servers.removeIf(server -> server.getLastUpdatedAt() < now - (5 * 60000));
+		}, 1, 1, TimeUnit.MINUTES);
+	}
+
+	@Override
+	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+		resp.setStatus(HttpServletResponse.SC_OK);
+		resp.setContentType("application/json");
+		mapper.writeValue(resp.getWriter(), servers);
+	}
+
+	@Override
+	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+		if (servers.size() > 10000) {
+			resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
+			resp.setContentType("application/json");
+			mapper.writeValue(resp.getWriter(), Map.of("message", "Too many servers registered at this time."));
+			return;
+		}
+		ServerMetaData data = mapper.readValue(req.getReader(), ServerMetaData.class);
+		data.setHost(req.getRemoteHost());
+		data.setLastUpdatedAt(System.currentTimeMillis());
+		synchronized (servers) {
+			servers.remove(data);
+			servers.add(data);
+		}
+		resp.setStatus(HttpServletResponse.SC_OK);
+		resp.setContentType("application/json");
+		mapper.writeValue(resp.getWriter(), data);
+	}
+}

catalog/src/main/resources/nl/andrewl/concord_catalog/defaults.properties

@@ -0,0 +1 @@
+port=25566

client/README.md

@@ -0,0 +1,3 @@
+# Concord Client
+
+The concord client is the application which users will run to connect to and interact with various servers. It displays a GUI in the terminal that shows recent chat messages, channels, and the list of users in a channel.

client/src/main/java/nl/andrewl/concord_client/gui/ChatRenderer.java

@@ -22,7 +22,7 @@ public class ChatRenderer extends AbstractListBox.ListItemRenderer<Chat, ChatLis
 		}
 		graphics.putString(0, 0, chat.getSenderNickname());
 		Instant timestamp = Instant.ofEpochMilli(chat.getTimestamp());
-		String timeStr = timestamp.atZone(ZoneId.systemDefault()).format(DateTimeFormatter.ofPattern("HH:mm:ss"));
+		String timeStr = timestamp.atZone(ZoneId.systemDefault()).format(DateTimeFormatter.ofPattern("HH:mm"));
 		String label = chat.getSenderNickname() + "@" + timeStr + " : " + chat.getMessage();
 		label = TerminalTextUtils.fitString(label, graphics.getSize().getColumns());
 		while(TerminalTextUtils.getColumnWidth(label) < graphics.getSize().getColumns()) {

core/README.md

@@ -0,0 +1,3 @@
+# Concord Core
+
+This module contains the core resources that both the client and server depend on.

pom.xml

@@ -12,6 +12,7 @@
         <module>server</module>
         <module>core</module>
         <module>client</module>
+        <module>catalog</module>
     </modules>
 
     <properties>

server/src/main/java/module-info.java

@@ -7,6 +7,7 @@ module concord_server {
 
 	requires java.base;
 	requires java.logging;
+	requires java.net.http;
 
 	requires concord_core;
 

server/src/main/java/nl/andrewl/concord_server/ChannelManager.java

@@ -23,6 +23,17 @@ public class ChannelManager {
 		return Set.copyOf(this.channelIdMap.values());
 	}
 
+	public Optional<Channel> getDefaultChannel() {
+		var optionalGeneral = this.getChannelByName("general");
+		if (optionalGeneral.isPresent()) {
+			return optionalGeneral;
+		}
+		for (var channel : this.getChannels()) {
+			return Optional.of(channel);
+		}
+		return Optional.empty();
+	}
+
 	public void addChannel(Channel channel) {
 		this.channelNameMap.put(channel.getName(), channel);
 		this.channelIdMap.put(channel.getId(), channel);

server/src/main/java/nl/andrewl/concord_server/ConcordServer.java

@@ -1,5 +1,8 @@
 package nl.andrewl.concord_server;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import lombok.Getter;
 import nl.andrewl.concord_core.msg.Message;
 import nl.andrewl.concord_core.msg.Serializer;
@@ -12,18 +15,21 @@ import nl.andrewl.concord_server.config.ServerConfig;
 import org.dizitart.no2.Nitrite;
 
 import java.io.ByteArrayOutputStream;
-import java.io.DataOutputStream;
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.net.ServerSocket;
 import java.net.Socket;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
 import java.nio.file.Path;
+import java.time.Duration;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.*;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
 import java.util.stream.Collectors;
 
 /**
@@ -46,6 +52,11 @@ public class ConcordServer implements Runnable {
 	@Getter
 	private final ChannelManager channelManager;
 
+	// Components for communicating with discovery servers.
+	private final ScheduledExecutorService scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
+	private final HttpClient httpClient = HttpClient.newHttpClient();
+	private final ObjectMapper mapper = new ObjectMapper();
+
 	public ConcordServer() {
 		this.idProvider = new UUIDProvider();
 		this.config = ServerConfig.loadOrCreate(Path.of("server-config.json"), idProvider);
@@ -53,7 +64,6 @@ public class ConcordServer implements Runnable {
 				.filePath("concord-server.db")
 				.openOrCreate();
 		this.clients = new ConcurrentHashMap<>(32);
-
 		this.executorService = Executors.newCachedThreadPool();
 		this.eventManager = new EventManager(this);
 		this.channelManager = new ChannelManager(this);
@@ -83,7 +93,7 @@ public class ConcordServer implements Runnable {
 		clientThread.setClientId(id);
 		clientThread.setClientNickname(identification.getNickname());
 		// Immediately add the client to the default channel and send the initial welcome message.
-		var defaultChannel = this.channelManager.getChannelByName("general").orElseThrow();
+		var defaultChannel = this.channelManager.getDefaultChannel().orElseThrow();
 		clientThread.sendToClient(new ServerWelcome(id, defaultChannel.getId(), this.getMetaData()));
 		// It is important that we send the welcome message first. The client expects this as the initial response to their identification message.
 		defaultChannel.addClient(clientThread);
@@ -143,9 +153,38 @@ public class ConcordServer implements Runnable {
 		}
 	}
 
+	private void publishMetaDataToDiscoveryServers() {
+		if (this.config.getDiscoveryServers().isEmpty()) return;
+		ObjectNode node = this.mapper.createObjectNode();
+		node.put("name", this.config.getName());
+		node.put("description", this.config.getDescription());
+		node.put("port", this.config.getPort());
+		String json;
+		try {
+			json = this.mapper.writeValueAsString(node);
+		} catch (JsonProcessingException e) {
+			throw new UncheckedIOException(e);
+		}
+		var discoveryServers = List.copyOf(this.config.getDiscoveryServers());
+		for (var discoveryServer : discoveryServers) {
+			System.out.println("Publishing this server's metadata to discovery server at " + discoveryServer);
+			var request = HttpRequest.newBuilder(URI.create(discoveryServer))
+					.POST(HttpRequest.BodyPublishers.ofString(json))
+					.header("Content-Type", "application/json")
+					.timeout(Duration.ofSeconds(3))
+					.build();
+			try {
+				this.httpClient.send(request, HttpResponse.BodyHandlers.discarding());
+			} catch (IOException | InterruptedException e) {
+				e.printStackTrace();
+			}
+		}
+	}
+
 	@Override
 	public void run() {
 		this.running = true;
+		this.scheduledExecutorService.scheduleAtFixedRate(this::publishMetaDataToDiscoveryServers, 1, 1, TimeUnit.MINUTES);
 		ServerSocket serverSocket;
 		try {
 			serverSocket = new ServerSocket(this.config.getPort());
@@ -163,6 +202,7 @@ public class ConcordServer implements Runnable {
 		} catch (IOException e) {
 			e.printStackTrace();
 		}
+		this.scheduledExecutorService.shutdown();
 	}
 
 	public static void main(String[] args) {

server/src/main/java/nl/andrewl/concord_server/cli/command/RemoveChannelCommand.java

@@ -39,5 +39,6 @@ public class RemoveChannelCommand implements ServerCliCommand {
 		server.getConfig().getChannels().removeIf(channelConfig -> channelConfig.getName().equals(channelToRemove.getName()));
 		server.getConfig().save();
 		server.broadcast(server.getMetaData());
+		System.out.println("Removed the channel " + channelToRemove);
 	}
 }

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

@@ -18,12 +18,15 @@ import java.util.List;
 @AllArgsConstructor
 public final class ServerConfig {
 	private String name;
+	private String description;
 	private int port;
 	private int chatHistoryMaxCount;
 	private int chatHistoryDefaultCount;
 	private int maxMessageLength;
 	private List<ChannelConfig> channels;
 
+	private List<String> discoveryServers;
+
 	/**
 	 * The path at which this config is stored.
 	 */
@@ -45,11 +48,13 @@ public final class ServerConfig {
 		if (Files.notExists(filePath)) {
 			config = new ServerConfig(
 					"My Concord Server",
+					"A concord server for my friends and I.",
 					8123,
 					100,
 					50,
 					8192,
 					List.of(new ChannelConfig(idProvider.newId().toString(), "general", "Default channel for general discussion.")),
+					List.of(),
 					filePath
 			);
 			try (var out = Files.newOutputStream(filePath)) {