Separate the dispatch and game servers (pt. 1)

gacha is still broken, handbook still needs to be done

src/main/java/emu/grasscutter/server/dispatch/DispatchServer.java

@@ -0,0 +1,165 @@
+package emu.grasscutter.server.dispatch;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.database.DatabaseHelper;
+import emu.grasscutter.utils.Crypto;
+import lombok.Getter;
+import org.java_websocket.WebSocket;
+import org.java_websocket.handshake.ClientHandshake;
+import org.java_websocket.server.WebSocketServer;
+import org.slf4j.Logger;
+
+import java.net.InetSocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+
+import static emu.grasscutter.config.Configuration.DISPATCH_INFO;
+
+/* Internal communications server. */
+public final class DispatchServer extends WebSocketServer implements IDispatcher {
+    @Getter private final Logger logger
+        = Grasscutter.getLogger();
+    @Getter private final Map<Integer, BiConsumer<WebSocket, JsonElement>> handlers
+        = new HashMap<>();
+
+    @Getter private final Map<Integer, List<Consumer<JsonElement>>> callbacks
+        = new HashMap<>();
+
+    /**
+     * Constructs a new {@code DispatchServer} instance.
+     *
+     * @param address The address to bind to.
+     * @param port The port to bind to.
+     */
+    public DispatchServer(String address, int port) {
+        super(new InetSocketAddress(address, port));
+
+        this.registerHandler(PacketIds.LoginNotify, this::handleLogin);
+        this.registerHandler(PacketIds.TokenValidateReq, this::validateToken);
+    }
+
+    /**
+     * Handles the login packet sent by the client.
+     *
+     * @param socket The socket the packet was received from.
+     * @param object The packet data.
+     */
+    private void handleLogin(WebSocket socket, JsonElement object) {
+        var dispatchKey = object.getAsString()
+            .replaceAll("\"", "");
+
+        // Check if the dispatch key is valid.
+        if (!dispatchKey.equals(DISPATCH_INFO.dispatchKey)) {
+            this.getLogger().warn("Invalid dispatch key received from {}.",
+                socket.getRemoteSocketAddress());
+            this.getLogger().debug("Expected: {}, Received: {}",
+                DISPATCH_INFO.dispatchKey, dispatchKey);
+            socket.close();
+        } else {
+            socket.setAttachment(true);
+        }
+    }
+
+    /**
+     * Handles the token validation packet sent by the client.
+     *
+     * @param socket The socket the packet was received from.
+     * @param object The packet data.
+     */
+    private void validateToken(WebSocket socket, JsonElement object) {
+        var message = IDispatcher.decode(object);
+        var accountId = message.get("uid").getAsString();
+        var token = message.get("token").getAsString();
+
+        // Get the account from the database.
+        var account = DatabaseHelper.getAccountById(accountId);
+        var valid = account != null && account.getToken().equals(token);
+        // Create the response message.
+        var response = new JsonObject();
+        response.addProperty("valid", valid);
+        if (valid) response.add("account",
+            JSON.toJsonTree(account));
+
+        // Send the response.
+        this.sendMessage(socket, PacketIds.TokenValidateRsp, response);
+    }
+
+    /**
+     * Broadcasts an encrypted message to all connected clients.
+     *
+     * @param message The message to broadcast.
+     */
+    public void sendMessage(int packetId, Object message) {
+        var serverMessage = this.encodeMessage(packetId, message);
+        this.getConnections().forEach(
+            socket -> this.sendMessage(socket, serverMessage));
+    }
+
+    /**
+     * Sends a serialized encrypted message to the client.
+     *
+     * @param socket The socket to send the message to.
+     * @param message The message to send.
+     */
+    public void sendMessage(WebSocket socket, Object message) {
+        // Serialize the message into JSON.
+        var serialized = JSON.toJson(message)
+            .getBytes(StandardCharsets.UTF_8);
+        // Encrypt the message.
+        Crypto.xor(serialized, DISPATCH_INFO.encryptionKey);
+        // Send the message.
+        socket.send(serialized);
+    }
+
+    /**
+     * Sends a serialized encrypted message to the client.
+     *
+     * @param socket The socket to send the message to.
+     * @param packetId The packet ID to send.
+     * @param message The message to send.
+     */
+    public void sendMessage(WebSocket socket, int packetId, Object message) {
+        this.sendMessage(socket, this.encodeMessage(packetId, message));
+    }
+
+    @Override
+    public void onStart() {
+        this.getLogger().info("Dispatch server started on port {}.",
+            this.getPort());
+    }
+
+    @Override
+    public void onOpen(WebSocket conn, ClientHandshake handshake) {
+        this.getLogger().debug("Dispatch client connected from {}.",
+            conn.getRemoteSocketAddress());
+    }
+
+    @Override
+    public void onMessage(WebSocket conn, String message) {
+        this.getLogger().debug("Received dispatch message from {}:\n{}",
+            conn.getRemoteSocketAddress(), message);
+    }
+
+    @Override
+    public void onMessage(WebSocket conn, ByteBuffer message) {
+        this.handleMessage(conn, message.array());
+    }
+
+    @Override
+    public void onClose(WebSocket conn, int code, String reason, boolean remote) {
+        this.getLogger().debug("Dispatch client disconnected from {}.",
+            conn.getRemoteSocketAddress());
+    }
+
+    @Override
+    public void onError(WebSocket conn, Exception ex) {
+        this.getLogger().warn("Dispatch server error.", ex);
+    }
+}