Added support for transferring players

api/src/main/java/org/geysermc/floodgate/api/FloodgateApi.java

@@ -95,6 +95,8 @@ public interface FloodgateApi {
 
     boolean sendForm(UUID uuid, FormBuilder<?, ?> formBuilder);
 
+    boolean transferPlayer(UUID uuid, String address, int port);
+
     /**
      * Get the xuid of the user that has the given gamertag.
      *

api/src/main/java/org/geysermc/floodgate/api/player/FloodgatePlayer.java

@@ -119,6 +119,10 @@ public interface FloodgatePlayer {
         return sendForm(formBuilder.build());
     }
 
+    default boolean transfer(String address, int port) {
+        return FloodgateApi.getInstance().transferPlayer(getCorrectUniqueId(), address, port);
+    }
+
     boolean hasProperty(PropertyKey key);
 
     boolean hasProperty(String key);

bungee/src/main/java/org/geysermc/floodgate/pluginmessage/BungeePluginMessageUtils.java

@@ -28,6 +28,7 @@ package org.geysermc.floodgate.pluginmessage;
 import java.util.UUID;
 import lombok.RequiredArgsConstructor;
 import net.md_5.bungee.ServerConnection;
+import net.md_5.bungee.api.ProxyServer;
 import net.md_5.bungee.api.chat.TextComponent;
 import net.md_5.bungee.api.connection.Connection;
 import net.md_5.bungee.api.connection.ProxiedPlayer;
@@ -96,4 +97,19 @@ public final class BungeePluginMessageUtils extends PluginMessageUtils implement
         logger.error(reason + " Closing connection");
         source.disconnect(new TextComponent(reason));
     }
+
+    @Override
+    public boolean sendMessage(UUID player, boolean toServer, String channel, byte[] data) {
+        ProxiedPlayer proxiedPlayer = ProxyServer.getInstance().getPlayer(player);
+        if (proxiedPlayer == null) {
+            return false;
+        }
+
+        if (toServer) {
+            proxiedPlayer.getServer().sendData(channel, data);
+        } else {
+            proxiedPlayer.sendData(channel, data);
+        }
+        return true;
+    }
 }

common/src/main/java/org/geysermc/floodgate/api/SimpleFloodgateApi.java

@@ -41,6 +41,7 @@ import org.geysermc.floodgate.config.FloodgateConfigHolder;
 import org.geysermc.floodgate.player.FloodgatePlayerImpl;
 import org.geysermc.floodgate.pluginmessage.PluginMessageManager;
 import org.geysermc.floodgate.pluginmessage.channel.FormChannel;
+import org.geysermc.floodgate.pluginmessage.channel.TransferChannel;
 import org.geysermc.floodgate.util.Constants;
 import org.geysermc.floodgate.util.HttpUtils;
 import org.geysermc.floodgate.util.Utils;
@@ -109,6 +110,13 @@ public class SimpleFloodgateApi implements FloodgateApi {
         return sendForm(uuid, formBuilder.build());
     }
 
+    @Override
+    public boolean transferPlayer(UUID uuid, String address, int port) {
+        return pluginMessageManager
+                .getChannel(TransferChannel.class)
+                .sendTransfer(uuid, address, port);
+    }
+
     @Override
     public CompletableFuture<Long> getXuidFor(String gamertag) {
         if (gamertag == null || gamertag.isEmpty() || gamertag.length() > 16) {

common/src/main/java/org/geysermc/floodgate/module/PluginMessageModule.java

@@ -31,6 +31,7 @@ import com.google.inject.multibindings.ProvidesIntoSet;
 import org.geysermc.floodgate.pluginmessage.PluginMessageChannel;
 import org.geysermc.floodgate.pluginmessage.channel.FormChannel;
 import org.geysermc.floodgate.pluginmessage.channel.SkinChannel;
+import org.geysermc.floodgate.pluginmessage.channel.TransferChannel;
 import org.geysermc.floodgate.register.PluginMessageRegister;
 
 public final class PluginMessageModule extends AbstractModule {
@@ -50,4 +51,10 @@ public final class PluginMessageModule extends AbstractModule {
     public PluginMessageChannel skinChannel() {
         return new SkinChannel();
     }
+
+    @Singleton
+    @ProvidesIntoSet
+    public PluginMessageChannel transferChannel() {
+        return new TransferChannel();
+    }
 }

common/src/main/java/org/geysermc/floodgate/pluginmessage/channel/TransferChannel.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.pluginmessage.channel;
+
+import com.google.inject.Inject;
+import java.nio.charset.StandardCharsets;
+import java.util.UUID;
+import org.geysermc.floodgate.platform.pluginmessage.PluginMessageUtils;
+import org.geysermc.floodgate.pluginmessage.PluginMessageChannel;
+
+public class TransferChannel implements PluginMessageChannel {
+    @Inject private PluginMessageUtils pluginMessageUtils;
+
+    @Override
+    public String getIdentifier() {
+        return "floodgate:transfer";
+    }
+
+    @Override
+    public Result handleProxyCall(
+            byte[] data,
+            UUID targetUuid,
+            String targetUsername,
+            Identity targetIdentity,
+            UUID sourceUuid,
+            String sourceUsername,
+            Identity sourceIdentity) {
+
+        if (sourceIdentity == Identity.SERVER) {
+            // send it to the client
+            return Result.forward();
+        }
+
+        if (sourceIdentity == Identity.PLAYER) {
+            handleServerCall(data, targetUuid, targetUsername);
+        }
+
+        return Result.handled();
+    }
+
+    @Override
+    public Result handleServerCall(byte[] data, UUID targetUuid, String targetUsername) {
+        return Result.kick("I'm sorry, I'm unable to transfer a server :(");
+    }
+
+    public boolean sendTransfer(UUID player, String address, int port) {
+        byte[] addressBytes = address.getBytes(StandardCharsets.UTF_8);
+        byte[] data = new byte[addressBytes.length + 4];
+
+        data[0] = (byte) (port >> 24);
+        data[1] = (byte) (port >> 16);
+        data[2] = (byte) (port >> 8);
+        data[3] = (byte) (port);
+        System.arraycopy(addressBytes, 0, data, 4, addressBytes.length);
+
+        return pluginMessageUtils.sendMessage(player, false, getIdentifier(), data);
+    }
+}