Update Version I accidentally deployed debug version - 0.5.1

Some README.md fixes.

ISSUE_TEMPLATE.md

@@ -0,0 +1,10 @@
+### What version of ViaVersion are you using? Type /ver viaversion
+
+### What version of Spigot are you using? Type /ver
+
+### What plugins are you using? /plugins
+
+### How does this error happen? login? using an item? 
+
+### Is there an error in the console? Use pastebin.com. Is there a kick message?
+

README.md

@@ -1,17 +1,9 @@
-# ViaVersion 0.4.3
-**Allows the connection of 1.8 clients to 1.9**
+# ViaVersion 0.5.1
+**Allows the connection of 1.9 clients to 1.8**
 
 This plugin modifies netty to allow connection of 1.9 clients to 1.8,
 
-**Don't use late bind*
-
-**As of this point it doesn't have everything, I need to fix:**
-
-Attempt to make boats nicer when they don't work
-
-Remap spawn eggs
-
-If you have a bug with entities, please report the full stack trace
+###**Don't use late bind*
 
 
 This took hours of work, so if you enjoy this consider looking into contacting me and supporting my projects.
@@ -24,6 +16,10 @@ Sources:
 
 **MCProtocolLib** (used for chunk reading & some of writing.)
 
+**OpenNBT** (used for slot rewriting)
+
+
+
 Contributors:
 --------
 
@@ -35,10 +31,22 @@ Contributors:
 
 **SanderGielisse**
 
+**Paulomart**
+
+**gigosaurus**
+
+**fillefilip8**
+
+**Chat: ** https://gitter.im/MylesIsCool/ViaVersion
+
+We use it to collaborate and solve errors, sign in with github.
+
 License:
 --------
 
 You may modify this work, all rights are still owned by myself excluding any files in the spacebase package as they belong to the respected contributors. Please credit the original author (myself) when forking etc. (or if it helped you understand the new protocol or netty!)
 
 
-Thanks!
+Thanks!
+
+

pom.xml

@@ -1,14 +1,30 @@
 <?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">
+<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">
     <modelVersion>4.0.0</modelVersion>
 
     <groupId>us.myles</groupId>
     <artifactId>ViaVersion</artifactId>
-    <version>1.0-SNAPSHOT</version>
+    <version>0.5.1</version>
     <build>
+        <finalName>ViaVersion-${version}</finalName>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>1.4</version>
+                <configuration>
+                    <createDependencyReducedPom>false</createDependencyReducedPom>
+                </configuration>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
@@ -18,8 +34,19 @@
                 </configuration>
             </plugin>
         </plugins>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
     </build>
     <dependencies>
+        <dependency>
+            <groupId>org.spacehq</groupId>
+            <artifactId>opennbt</artifactId>
+            <version>1.0</version>
+        </dependency>
         <dependency>
             <groupId>org.bukkit</groupId>
             <artifactId>bukkit</artifactId>
@@ -50,5 +77,9 @@
             <id>spigot-repo</id>
             <url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
         </repository>
-   </repositories>
+        <repository>
+            <id>spacehq-repo</id>
+            <url>https://repo.spacehq.org/content/repositories/releases/</url>
+        </repository>
+    </repositories>
 </project>

src/main/java/us/myles/ViaVersion/ConnectionInfo.java

@@ -1,5 +1,7 @@
 package us.myles.ViaVersion;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandler;
 import io.netty.channel.socket.SocketChannel;
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
@@ -75,4 +77,14 @@ public class ConnectionInfo {
     public void setActive(boolean active) {
         this.active = active;
     }
+
+    public void sendRawPacket(final ByteBuf packet) {
+        final ChannelHandler handler = channel.pipeline().get("encoder");
+        channel.eventLoop().submit(new Runnable() {
+            @Override
+            public void run() {
+                channel.pipeline().context(handler).writeAndFlush(packet);
+            }
+        });
+    }
 }

src/main/java/us/myles/ViaVersion/ViaVersionPlugin.java

@@ -1,5 +1,6 @@
 package us.myles.ViaVersion;
 
+import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelInitializer;
@@ -12,15 +13,16 @@ import org.bukkit.event.Listener;
 import org.bukkit.event.player.PlayerQuitEvent;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.plugin.java.JavaPlugin;
-
 import us.myles.ViaVersion.api.ViaVersion;
 import us.myles.ViaVersion.api.ViaVersionAPI;
+import us.myles.ViaVersion.armor.ArmorListener;
+import us.myles.ViaVersion.commands.ViaVersionCommand;
 import us.myles.ViaVersion.handlers.ViaVersionInitializer;
 import us.myles.ViaVersion.util.ReflectionUtil;
 
-import java.util.Collections;
+import java.lang.reflect.Field;
 import java.util.List;
-import java.util.Set;
+import java.util.Map;
 import java.util.UUID;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ConcurrentHashMap;
@@ -28,17 +30,17 @@ import java.util.concurrent.TimeUnit;
 
 public class ViaVersionPlugin extends JavaPlugin implements ViaVersionAPI {
 
-    private final Set<UUID> portedPlayers = Collections.newSetFromMap(new ConcurrentHashMap<UUID, Boolean>());
+    private final Map<UUID, ConnectionInfo> portedPlayers = new ConcurrentHashMap<UUID, ConnectionInfo>();
 
     @Override
     public void onEnable() {
         ViaVersion.setInstance(this);
-        if(System.getProperty("ViaVersion") != null){
+        if (System.getProperty("ViaVersion") != null) {
             getLogger().severe("ViaVersion is already loaded, we don't support reloads. Please reboot if you wish to update.");
             return;
         }
 
-        getLogger().info("ViaVersion enabled, injecting. (Allows 1.8 to be accessed via 1.9)");
+        getLogger().info("ViaVersion " + getDescription().getVersion() + " is now enabled, injecting. (Allows 1.8 to be accessed via 1.9)");
         try {
             injectPacketHandler();
             System.setProperty("ViaVersion", getDescription().getVersion());
@@ -46,44 +48,71 @@ public class ViaVersionPlugin extends JavaPlugin implements ViaVersionAPI {
             getLogger().severe("Unable to inject handlers, are you on 1.8? ");
             e.printStackTrace();
         }
+
         Bukkit.getPluginManager().registerEvents(new Listener() {
             @EventHandler
             public void onPlayerQuit(PlayerQuitEvent e) {
-                setPorted(e.getPlayer().getUniqueId(), false);
+                removePortedClient(e.getPlayer().getUniqueId());
             }
         }, this);
+
+        Bukkit.getPluginManager().registerEvents(new ArmorListener(this), this);
+
+        getCommand("viaversion").setExecutor(new ViaVersionCommand());
     }
 
     public void injectPacketHandler() throws Exception {
         Class<?> serverClazz = ReflectionUtil.nms("MinecraftServer");
         Object server = ReflectionUtil.invokeStatic(serverClazz, "getServer");
         Object connection = serverClazz.getDeclaredMethod("getServerConnection").invoke(server);
-
-        List<ChannelFuture> futures = ReflectionUtil.get(connection, "g", List.class);
-        if (futures.size() == 0) {
-            throw new Exception("Could not find server to inject (Please ensure late-bind in your spigot.yml is false)");
+        // loop through all fields checking if list
+        boolean injected = false;
+        for (Field field : connection.getClass().getDeclaredFields()) {
+            field.setAccessible(true);
+            Object value = field.get(connection);
+            if (value instanceof List) {
+                for (Object o : (List) value) {
+                    if (o instanceof ChannelFuture) {
+                        ChannelFuture future = (ChannelFuture) o;
+                        ChannelPipeline pipeline = future.channel().pipeline();
+                        ChannelHandler bootstrapAcceptor = pipeline.first();
+                        ChannelInitializer<SocketChannel> oldInit = ReflectionUtil.get(bootstrapAcceptor, "childHandler", ChannelInitializer.class);
+                        ChannelInitializer newInit = new ViaVersionInitializer(oldInit);
+                        ReflectionUtil.set(bootstrapAcceptor, "childHandler", newInit);
+                        injected = true;
+                    } else {
+                        break; // not the right list.
+                    }
+                }
+            }
         }
-
-        for (ChannelFuture future : futures) {
-            ChannelPipeline pipeline = future.channel().pipeline();
-            ChannelHandler bootstrapAcceptor = pipeline.first();
-            ChannelInitializer<SocketChannel> oldInit = ReflectionUtil.get(bootstrapAcceptor, "childHandler", ChannelInitializer.class);
-            ChannelInitializer newInit = new ViaVersionInitializer(oldInit);
-            ReflectionUtil.set(bootstrapAcceptor, "childHandler", newInit);
+        if (!injected) {
+            throw new Exception("Could not find server to inject (Please ensure late-bind in your spigot.yml is false)");
         }
     }
 
     @Override
     public boolean isPorted(Player player) {
-        return portedPlayers.contains(player.getUniqueId());
+        return portedPlayers.containsKey(player.getUniqueId());
     }
 
-    public void setPorted(UUID id, boolean value) {
-        if (value) {
-            portedPlayers.add(id);
-        } else {
-            portedPlayers.remove(id);
-        }
+    @Override
+    public String getVersion() {
+        return getDescription().getVersion();
+    }
+
+    public void sendRawPacket(Player player, ByteBuf packet) throws IllegalArgumentException {
+        if (!isPorted(player)) throw new IllegalArgumentException("This player is not on 1.9");
+        ConnectionInfo ci = portedPlayers.get(player.getUniqueId());
+        ci.sendRawPacket(packet);
+    }
+
+    public void addPortedClient(ConnectionInfo info) {
+        portedPlayers.put(info.getUUID(), info);
+    }
+
+    public void removePortedClient(UUID clientID) {
+        portedPlayers.remove(clientID);
     }
 
     public static ItemStack getHandItem(final ConnectionInfo info) {

src/main/java/us/myles/ViaVersion/api/ViaVersionAPI.java

@@ -1,8 +1,27 @@
 package us.myles.ViaVersion.api;
 
+import io.netty.buffer.ByteBuf;
 import org.bukkit.entity.Player;
 
 public interface ViaVersionAPI {
-
+    /**
+     * Is player using 1.9?
+     * @param player
+     * @return True if the client is on 1.9
+     */
     boolean isPorted(Player player);
+
+    /**
+     * Get the version of the plugin
+     * @return Plugin version
+     */
+    String getVersion();
+
+    /**
+     * Send a raw packet to the player (Use new IDs)
+     * @param player The player to send packet
+     * @param packet The packet, you need a VarInt ID then the packet contents.
+     * @throws IllegalArgumentException If not on 1.9 throws IllegalArg
+     */
+    void sendRawPacket(Player player, ByteBuf packet) throws IllegalArgumentException;
 }

src/main/java/us/myles/ViaVersion/armor/ArmorListener.java

@@ -0,0 +1,106 @@
+package us.myles.ViaVersion.armor;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.block.Action;
+import org.bukkit.event.inventory.InventoryClickEvent;
+import org.bukkit.event.player.PlayerInteractEvent;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.inventory.CraftingInventory;
+import us.myles.ViaVersion.ViaVersionPlugin;
+import us.myles.ViaVersion.api.ViaVersion;
+import us.myles.ViaVersion.packets.PacketType;
+
+import java.util.UUID;
+
+import static us.myles.ViaVersion.util.PacketUtil.*;
+
+public class ArmorListener implements Listener {
+
+    private final ViaVersionPlugin plugin;
+
+    private static UUID armorAttribute = UUID.fromString("2AD3F246-FEE1-4E67-B886-69FD380BB150");
+
+    public ArmorListener(ViaVersionPlugin plugin) {
+        this.plugin = plugin;
+    }
+
+    @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
+    public void onInventoryClick(InventoryClickEvent e) {
+        HumanEntity human = e.getWhoClicked();
+        if (human instanceof Player && e.getInventory() instanceof CraftingInventory) {
+            final Player player = (Player) human;
+            if (ViaVersion.getInstance().isPorted(player)) {
+                if (e.getCurrentItem() != null) {
+                    if (ArmorType.isArmor(e.getCurrentItem().getType())) {
+                        sendDelayedArmorUpdate(player);
+                        return;
+                    }
+                }
+                if (e.getRawSlot() >= 5 && e.getRawSlot() <= 8) {
+                    sendDelayedArmorUpdate(player);
+                    return;
+                }
+            }
+        }
+    }
+
+    @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
+    public void onInteract(PlayerInteractEvent e) {
+        if (e.getItem() != null) {
+            if (e.getAction() == Action.RIGHT_CLICK_AIR || e.getAction() == Action.RIGHT_CLICK_BLOCK) {
+                if (ArmorType.isArmor(e.getMaterial())) {
+                    final Player player = e.getPlayer();
+                    // Due to odd bugs it's 3 ticks later
+                    Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
+                        @Override
+                        public void run() {
+                            if (ViaVersion.getInstance().isPorted(player)) {
+                                sendArmorUpdate(player);
+                            }
+                        }
+                    }, 3L);
+                }
+            }
+        }
+    }
+
+    @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
+    public void onJoin(PlayerJoinEvent e) {
+        sendDelayedArmorUpdate(e.getPlayer());
+    }
+
+    public void sendDelayedArmorUpdate(final Player player) {
+        Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
+            @Override
+            public void run() {
+                if (ViaVersion.getInstance().isPorted(player)) {
+                    sendArmorUpdate(player);
+                }
+            }
+        });
+    }
+
+    public static void sendArmorUpdate(Player player) {
+        int armor = ArmorType.calculateArmorPoints(player.getInventory().getArmorContents());
+
+        ByteBuf buf = Unpooled.buffer();
+        writeVarInt(PacketType.PLAY_ENTITY_PROPERTIES.getNewPacketID(), buf);
+        writeVarInt(player.getEntityId(), buf);
+        buf.writeInt(1); // only 1 property
+        writeString("generic.armor", buf);
+        buf.writeDouble(0); //default 0 armor
+        writeVarInt(1, buf); // 1 modifier
+        writeUUID(armorAttribute, buf); // armor modifier uuid
+        buf.writeDouble((double) armor); // the modifier value
+        buf.writeByte(0); // the modifier operation, 0 is add number
+
+        ViaVersion.getInstance().sendRawPacket(player, buf);
+    }
+}

src/main/java/us/myles/ViaVersion/armor/ArmorType.java

@@ -0,0 +1,91 @@
+package us.myles.ViaVersion.armor;
+
+import org.bukkit.Material;
+import org.bukkit.inventory.ItemStack;
+
+public enum ArmorType {
+
+    LEATHER_HELMET(1, 298, Material.LEATHER_HELMET),
+    LEATHER_CHESTPLATE(3, 299, Material.LEATHER_CHESTPLATE),
+    LEATHER_LEGGINGS(2, 300, Material.LEATHER_LEGGINGS),
+    LEATHER_BOOTS(1, 301, Material.LEATHER_BOOTS),
+    CHAINMAIL_HELMET(2, 302, Material.CHAINMAIL_HELMET),
+    CHAINMAIL_CHESTPLATE(5, 303, Material.CHAINMAIL_CHESTPLATE),
+    CHAINMAIL_LEGGINGS(4, 304, Material.CHAINMAIL_LEGGINGS),
+    CHAINMAIL_BOOTS(1, 305, Material.CHAINMAIL_BOOTS),
+    IRON_HELMET(2, 306, Material.IRON_HELMET),
+    IRON_CHESTPLATE(6, 307, Material.IRON_CHESTPLATE),
+    IRON_LEGGINGS(5, 308, Material.IRON_LEGGINGS),
+    IRON_BOOTS(2, 309, Material.IRON_BOOTS),
+    DIAMOND_HELMET(3, 310, Material.DIAMOND_HELMET),
+    DIAMOND_CHESTPLATE(8, 311, Material.DIAMOND_CHESTPLATE),
+    DIAMOND_LEGGINGS(6, 312, Material.DIAMOND_LEGGINGS),
+    DIAMOND_BOOTS(3, 313, Material.DIAMOND_BOOTS),
+    GOLD_HELMET(2, 314, Material.GOLD_HELMET),
+    GOLD_CHESTPLATE(5, 315, Material.GOLD_CHESTPLATE),
+    GOLD_LEGGINGS(3, 316, Material.GOLD_LEGGINGS),
+    GOLD_BOOTS(1, 317, Material.GOLD_BOOTS),
+    NONE(0, 0, Material.AIR);
+
+    private int armorpoints;
+    private int id;
+    private Material type;
+
+    ArmorType(int armor, int id, Material type) {
+        this.armorpoints = armor;
+        this.id = id;
+        this.type = type;
+    }
+
+    public int getArmorPoints() {
+        return this.armorpoints;
+    }
+
+    public int getId() {
+        return this.id;
+    }
+
+    public Material getType() {
+        return this.type;
+    }
+
+    public static ArmorType findByType(Material type) {
+        for(ArmorType a : ArmorType.values())
+            if(a.getType() == type)
+                return a;
+        return ArmorType.NONE;
+    }
+
+    public static int calculateArmorPoints(ItemStack[] armor) {
+        int total = 0;
+        for(int i = 0; i < armor.length; i++) {
+            if(armor[i] != null)
+                total += findByType(armor[i].getType()).getArmorPoints();
+        }
+        return total;
+    }
+
+    public static ArmorType findById(int id) {
+        for(ArmorType a : ArmorType.values())
+            if(a.getId() == id)
+                return a;
+        return ArmorType.NONE;
+    }
+
+    public static boolean isArmor(Material material){
+        for(ArmorType a : ArmorType.values())
+            if(a.getType() == material)
+                return true;
+        return false;
+    }
+
+    public static int calculateArmorPoints(int[] armor) {
+        int total = 0;
+        for(int i = 0; i < armor.length; i++) {
+            if(armor[i] != -1)
+                total += findById(armor[i]).getArmorPoints();
+        }
+        return total;
+    }
+
+}

src/main/java/us/myles/ViaVersion/commands/ViaVersionCommand.java

@@ -0,0 +1,48 @@
+package us.myles.ViaVersion.commands;
+
+import org.bukkit.Bukkit;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import us.myles.ViaVersion.api.ViaVersion;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by fillefilip8 on 2016-03-03.
+ */
+public class ViaVersionCommand implements CommandExecutor {
+
+    @Override
+    public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
+        if (sender.hasPermission("viaversion.admin")) {
+            if (args.length == 0) {
+                sender.sendMessage(color("&aViaVersion &c" + ViaVersion.getInstance().getVersion()));
+                sender.sendMessage(color("&6Commands:"));
+                sender.sendMessage(color("&2/viaversion list &7- &6Shows lists of all 1.9 clients and 1.8 clients."));
+            } else if (args.length == 1) {
+                if (args[0].equalsIgnoreCase("list")) {
+                    List<String> portedPlayers = new ArrayList<String>();
+                    List<String> normalPlayers = new ArrayList<String>();
+                    for (Player p : Bukkit.getOnlinePlayers()) {
+                        if (ViaVersion.getInstance().isPorted(p)) {
+                            portedPlayers.add(p.getName());
+                        } else {
+                            normalPlayers.add(p.getName());
+                        }
+                    }
+
+                    sender.sendMessage(color("&8[&61.9&8]: &b" + portedPlayers.toString()));
+                    sender.sendMessage(color("&8[&61.8&8]: &b" + normalPlayers.toString()));
+                }
+            }
+
+        }
+        return false;
+    }
+    public String color(String string){
+        return string.replace("&", "§");
+    }
+}

src/main/java/us/myles/ViaVersion/handlers/ViaDecodeHandler.java

@@ -31,6 +31,7 @@ public class ViaDecodeHandler extends ByteToMessageDecoder {
                 ByteBuf newPacket = ctx.alloc().buffer();
                 try {
                     incomingTransformer.transform(id, bytebuf, newPacket);
+                    bytebuf.readBytes(bytebuf.readableBytes());
                     bytebuf = newPacket;
                 } catch (CancelException e) {
                     bytebuf.readBytes(bytebuf.readableBytes());
@@ -44,15 +45,7 @@ public class ViaDecodeHandler extends ByteToMessageDecoder {
 
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
-        if (!(cause.getCause().getCause() instanceof CancelException)) {
-            if (!(cause.getCause() instanceof CancelException)) {
-                if (!(cause instanceof CancelException)) {
-                    System.out.println("throwing");
-                    if (cause instanceof Exception)
-                        throw (Exception) cause;
-                }
-            }
-        }
+        if (PacketUtil.containsCause(cause, CancelException.class)) return;
+        super.exceptionCaught(ctx, cause);
     }
-
 }

src/main/java/us/myles/ViaVersion/handlers/ViaEncodeHandler.java

@@ -10,6 +10,7 @@ import us.myles.ViaVersion.util.PacketUtil;
 import us.myles.ViaVersion.util.ReflectionUtil;
 
 import java.lang.reflect.Constructor;
+import java.nio.channels.ClosedChannelException;
 
 public class ViaEncodeHandler extends MessageToByteEncoder {
     private final ConnectionInfo info;
@@ -71,14 +72,7 @@ public class ViaEncodeHandler extends MessageToByteEncoder {
 
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
-        if (!(cause.getCause().getCause() instanceof CancelException)) {
-            if (!(cause.getCause() instanceof CancelException)) {
-                if (!(cause instanceof CancelException)) {
-                    System.out.println("throwing");
-                    if (cause instanceof Exception)
-                        throw (Exception) cause;
-                }
-            }
-        }
+        if (PacketUtil.containsCause(cause, CancelException.class)) return;
+        super.exceptionCaught(ctx, cause);
     }
 }

src/main/java/us/myles/ViaVersion/metadata/MetaIndex.java

@@ -27,10 +27,10 @@ public enum MetaIndex {
     STAND_LL_POS(ArmorStand.class, 15, Type.Rotation, NewType.Vector3F),
     STAND_RL_POS(ArmorStand.class, 16, Type.Rotation, NewType.Vector3F),
     // human, discountined?
-    PLAYER_SKIN_FLAGS(HumanEntity.class, 10, Type.Byte, NewType.Discontinued), // unsigned on 1.8
+    PLAYER_SKIN_FLAGS(HumanEntity.class, 10, Type.Byte, 12, NewType.Byte), // unsigned on 1.8
     PLAYER_HUMAN_BYTE(HumanEntity.class, 16, Type.Byte, NewType.Discontinued), // unused on 1.8
-    PLAYER_ADDITIONAL_HEARTS(HumanEntity.class, 17, Type.Float, NewType.Discontinued),
-    PLAYER_SCORE(HumanEntity.class, 18, Type.Int, NewType.Discontinued),
+    PLAYER_ADDITIONAL_HEARTS(HumanEntity.class, 17, Type.Float, 10, NewType.Float),
+    PLAYER_SCORE(HumanEntity.class, 18, Type.Int, 11, NewType.VarInt),
     // horse
     HORSE_INFO(Horse.class, 16, Type.Int, 12, NewType.Byte),
     HORSE_TYPE(Horse.class, 19, Type.Byte, 13, NewType.VarInt),
@@ -88,6 +88,8 @@ public enum MetaIndex {
     WITHER_TARGET2(Wither.class, 18, Type.Int, 12, NewType.VarInt),
     WITHER_TARGET3(Wither.class, 19, Type.Int, 13, NewType.VarInt),
     WITHER_INVULN_TIME(Wither.class, 20, Type.Int, 14, NewType.VarInt),
+    // wither skull
+    WITHERSKULL_INVULN(WitherSkull.class, 10, Type.Byte, 5, NewType.Boolean),
     // guardian
     GUARDIAN_INFO(Guardian.class, 16, Type.Int, 11, NewType.Byte),
     GUARDIAN_TARGET(Guardian.class, 17, Type.Int, 12, NewType.VarInt),

src/main/java/us/myles/ViaVersion/metadata/MetadataRewriter.java

@@ -0,0 +1,195 @@
+package us.myles.ViaVersion.metadata;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.UUID;
+
+import org.bukkit.entity.EntityType;
+import org.bukkit.util.EulerAngle;
+import org.bukkit.util.Vector;
+
+import io.netty.buffer.ByteBuf;
+
+import us.myles.ViaVersion.slot.ItemSlotRewriter;
+import us.myles.ViaVersion.slot.ItemSlotRewriter.ItemStack;
+import us.myles.ViaVersion.util.PacketUtil;
+
+public class MetadataRewriter {
+
+    public static void writeMetadata1_9(EntityType type, List<Entry> list, ByteBuf output) {
+        short id = -1;
+        int data = -1;
+        Iterator<Entry> iterator = list.iterator();
+        while (iterator.hasNext()) {
+            Entry entry = iterator.next(); //
+            MetaIndex metaIndex = entry.index;
+            try {
+                if (metaIndex.getNewType() != NewType.Discontinued) {
+                    if (metaIndex.getNewType() != NewType.BlockID || id != -1 && data == -1 || id == -1 && data != -1) { // block ID is only written if we have both parts
+                        output.writeByte(metaIndex.getNewIndex());
+                        output.writeByte(metaIndex.getNewType().getTypeID());
+                    }
+                    Object value = entry.value;
+                    switch (metaIndex.getNewType()) {
+                        case Byte:
+                            // convert from int, byte
+                            if (metaIndex.getOldType() == Type.Byte) {
+                                output.writeByte(((Byte) value).byteValue());
+                            }
+                            if (metaIndex.getOldType() == Type.Int) {
+                                output.writeByte(((Integer) value).byteValue());
+                            }
+                            break;
+                        case OptUUID:
+                            String owner = (String) value;
+                            UUID toWrite = null;
+                            if (owner.length() != 0) {
+                                try {
+                                    toWrite = UUID.fromString(owner);
+                                } catch (Exception ignored) {
+                                }
+                            }
+                            output.writeBoolean(toWrite != null);
+                            if (toWrite != null)
+                                PacketUtil.writeUUID((UUID) toWrite, output);
+                            break;
+                        case BlockID:
+                            // if we have both sources :))
+                            if (metaIndex.getOldType() == Type.Byte) {
+                                data = ((Byte) value).byteValue();
+                            }
+                            if (metaIndex.getOldType() == Type.Short) {
+                                id = ((Short) value).shortValue();
+                            }
+                            if (id != -1 && data != -1) {
+                                int combined = id << 4 | data;
+                                data = -1;
+                                id = -1;
+                                PacketUtil.writeVarInt(combined, output);
+                            }
+                            break;
+                        case VarInt:
+                            // convert from int, short, byte
+                            if (metaIndex.getOldType() == Type.Byte) {
+                                PacketUtil.writeVarInt(((Byte) value).intValue(), output);
+                            }
+                            if (metaIndex.getOldType() == Type.Short) {
+                                PacketUtil.writeVarInt(((Short) value).intValue(), output);
+                            }
+                            if (metaIndex.getOldType() == Type.Int) {
+                                PacketUtil.writeVarInt(((Integer) value).intValue(), output);
+                            }
+                            break;
+                        case Float:
+                            output.writeFloat(((Float) value).floatValue());
+                            break;
+                        case String:
+                            PacketUtil.writeString((String) value, output);
+                            break;
+                        case Boolean:
+                            if(metaIndex == MetaIndex.AGEABLE_AGE)
+                                output.writeBoolean(((Byte) value).byteValue() < 0);
+                            else
+                                output.writeBoolean(((Byte) value).byteValue() != 0);
+                            break;
+                        case Slot:
+                            ItemStack item = (ItemStack) value;
+                            ItemSlotRewriter.fixIdsFrom1_8To1_9(item);
+                            ItemSlotRewriter.writeItemStack(item, output);
+                            break;
+                        case Position:
+                            Vector vector = (Vector) value;
+                            output.writeInt((int) vector.getX());
+                            output.writeInt((int) vector.getY());
+                            output.writeInt((int) vector.getZ());
+                            break;
+                        case Vector3F:
+                            EulerAngle angle = (EulerAngle) value;
+                            output.writeFloat((float) angle.getX());
+                            output.writeFloat((float) angle.getY());
+                            output.writeFloat((float) angle.getZ());
+                            break;
+                        default:
+                            System.out.println("[Out] Unhandled MetaDataType: " + metaIndex.getNewType());
+                            break;
+                    }
+                }
+            } catch (Exception e) {
+                if (type != null) {
+                    System.out.println("An error occurred with entity meta data for " + type);
+                    if (metaIndex != null) {
+                        System.out.println("Old ID: " + metaIndex.getIndex() + " New ID: " + metaIndex.getNewIndex());
+                        System.out.println("Old Type: " + metaIndex.getOldType() + " New Type: " + metaIndex.getNewType());
+                    }
+                }
+                e.printStackTrace();
+            }
+        }
+        output.writeByte(255);
+    }
+
+    public static List<Entry> readMetadata1_8(EntityType entityType, ByteBuf buf) {
+        List<Entry> entries = new ArrayList<>();
+        byte item;
+        while ((item = buf.readByte()) != 127) {
+            Type type = Type.byId((item & 0xE0) >> 5);
+            int id = item & 0x1F;
+            MetaIndex index = MetaIndex.getIndex(entityType, id);
+            switch (type) {
+                case Byte:
+                    entries.add(new Entry(index, buf.readByte()));
+                    break;
+                case Short:
+                    entries.add(new Entry(index, buf.readShort()));
+                    break;
+                case Int:
+                    entries.add(new Entry(index, buf.readInt()));
+                    break;
+                case Float:
+                    entries.add(new Entry(index, buf.readFloat()));
+                    break;
+                case String:
+                    entries.add(new Entry(index, PacketUtil.readString(buf)));
+                    break;
+                case Slot: {
+                    try {
+                        entries.add(new Entry(index, ItemSlotRewriter.readItemStack(buf)));
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    }
+                }
+                    break;
+                case Position: {
+                    int x = buf.readInt();
+                    int y = buf.readInt();
+                    int z = buf.readInt();
+                    entries.add(new Entry(index, new Vector(x, y, z)));
+                    break;
+                }
+                case Rotation: {
+                    float x = buf.readFloat();
+                    float y = buf.readFloat();
+                    float z = buf.readFloat();
+                    entries.add(new Entry(index, new EulerAngle(x, y, z)));
+                    break;
+                }
+                default:
+                    System.out.println("[Out] Unhandled MetaDataType: " + type);
+                    break;
+            }
+        }
+        return entries;
+    }
+
+    public static class Entry {
+
+        private MetaIndex index;
+        private Object value;
+
+        private Entry(MetaIndex index, Object value) {
+            this.index = index;
+            this.value = value;
+        }
+    }
+}

src/main/java/us/myles/ViaVersion/metadata/Type.java

@@ -18,4 +18,8 @@ public enum Type {
     public int getTypeID() {
         return typeID;
     }
+
+    public static Type byId(int id) {
+        return values()[id];
+    }
 }

src/main/java/us/myles/ViaVersion/packets/PacketType.java

@@ -96,7 +96,7 @@ public enum PacketType {
     PLAY_COMBAT_EVENT(State.PLAY, Direction.OUTGOING, 0x42, 0x2C),
     PLAY_PLAYER_LIST_ITEM(State.PLAY, Direction.OUTGOING, 0x38, 0x2D),
     PLAY_PLAYER_POSITION_LOOK(State.PLAY, Direction.OUTGOING, 0x08, 0x2E),
-    PLAY_USE_BED(State.PLAY, Direction.OUTGOING, 0x2F, 0x2F),
+    PLAY_USE_BED(State.PLAY, Direction.OUTGOING, 0x0A, 0x2F),
     PLAY_DESTROY_ENTITIES(State.PLAY, Direction.OUTGOING, 0x13, 0x30),
     PLAY_REMOVE_ENTITY_EFFECT(State.PLAY, Direction.OUTGOING, 0x1E, 0x31),
     PLAY_RESOURCE_PACK_SEND(State.PLAY, Direction.OUTGOING, 0x48, 0x32),
@@ -170,7 +170,7 @@ public enum PacketType {
     	if(id == -1)
     		return null;
         for (PacketType pt : values()) {
-            if (pt.getNewPacketID() == id && id != -1
+            if (pt.getNewPacketID() == id
                     && pt.getState() == state
                     && pt.getDirection() == direction)
                 return pt;
@@ -182,7 +182,7 @@ public enum PacketType {
     	if(id == -1)
     		return null;
         for (PacketType pt : values()) {
-            if (pt.getPacketID() == id && id != -1
+            if (pt.getPacketID() == id
                     && pt.getState() == state
                     && pt.getDirection() == direction)
                 return pt;

src/main/java/us/myles/ViaVersion/slot/ItemSlotRewriter.java

@@ -0,0 +1,297 @@
+package us.myles.ViaVersion.slot;
+
+import io.netty.buffer.ByteBuf;
+import org.bukkit.Material;
+import org.spacehq.opennbt.tag.builtin.CompoundTag;
+import org.spacehq.opennbt.tag.builtin.StringTag;
+import us.myles.ViaVersion.CancelException;
+import us.myles.ViaVersion.util.PacketUtil;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class ItemSlotRewriter {
+
+    public static void rewrite1_9To1_8(ByteBuf input, ByteBuf output) throws CancelException {
+        try {
+            ItemStack item = readItemStack(input);
+            fixIdsFrom1_9To1_8(item);
+            writeItemStack(item, output);
+        } catch (Exception e) {
+            System.out.println("Error while rewriting an item slot.");
+            e.printStackTrace();
+            throw new CancelException();
+        }
+    }
+
+    public static void rewrite1_8To1_9(ByteBuf input, ByteBuf output) throws CancelException {
+        try {
+            ItemStack item = readItemStack(input);
+            fixIdsFrom1_8To1_9(item);
+            writeItemStack(item, output);
+        } catch (Exception e) {
+            System.out.println("Error while rewriting an item slot.");
+            e.printStackTrace();
+            throw new CancelException();
+        }
+    }
+
+    public static void fixIdsFrom1_9To1_8(ItemStack item) {
+        if (item != null) {
+            if (item.id == Material.MONSTER_EGG.getId() && item.data == 0) {
+                CompoundTag tag = item.tag;
+                int data = 0;
+                if (tag != null && tag.get("EntityTag") instanceof CompoundTag) {
+                    CompoundTag entityTag = tag.get("EntityTag");
+                    if (entityTag.get("id") instanceof StringTag) {
+                        StringTag id = entityTag.get("id");
+                        if (ENTTIY_NAME_TO_ID.containsKey(id.getValue()))
+                            data = ENTTIY_NAME_TO_ID.get(id.getValue());
+                    }
+                }
+                item.tag = null;
+                item.data = (short) data;
+            }
+            if (item.id == Material.POTION.getId()) {
+                CompoundTag tag = item.tag;
+                int data = 0;
+                if (tag != null && tag.get("Potion") instanceof StringTag) {
+                    StringTag potion = tag.get("Potion");
+                    String potionName = potion.getValue().replace("minecraft:", "");
+                    if (POTION_NAME_TO_ID.containsKey(potionName)) {
+                        data = POTION_NAME_TO_ID.get(potionName);
+                    }
+                }
+                item.tag = null;
+                item.data = (short) data;
+            }
+            if (item.id == 438) {
+                CompoundTag tag = item.tag;
+                int data = 0;
+                item.id = (short) Material.POTION.getId();
+                if (tag != null && tag.get("Potion") instanceof StringTag) {
+                    StringTag potion = tag.get("Potion");
+                    String potionName = potion.getValue().replace("minecraft:", "");
+                    if (POTION_NAME_TO_ID.containsKey(potionName)) {
+                        data = POTION_NAME_TO_ID.get(potionName) + 8192;
+                    }
+                }
+                item.tag = null;
+                item.data = (short) data;
+            }
+        }
+    }
+
+    public static void fixIdsFrom1_8To1_9(ItemStack item) {
+        if (item != null) {
+            if (item.id == Material.MONSTER_EGG.getId() && item.data != 0) {
+                CompoundTag tag = item.tag;
+                if (tag == null) {
+                    tag = new CompoundTag("tag");
+                }
+                CompoundTag entityTag = new CompoundTag("EntityTag");
+                if (ENTTIY_ID_TO_NAME.containsKey(Integer.valueOf(item.data))) {
+                    StringTag id = new StringTag("id", ENTTIY_ID_TO_NAME.get(Integer.valueOf(item.data)));
+                    entityTag.put(id);
+                    tag.put(entityTag);
+                }
+                item.tag = tag;
+                item.data = 0;
+            }
+            if (item.id == Material.POTION.getId()) {
+                CompoundTag tag = item.tag;
+                if (tag == null) {
+                    tag = new CompoundTag("tag");
+                }
+                if(item.data >= 16384){
+                    item.id = 438; // splash id
+                    item.data = (short) (item.data - 8192);
+                }
+                if (POTION_ID_TO_NAME.containsKey(Integer.valueOf(item.data))) {
+                    String name = POTION_ID_TO_NAME.get(Integer.valueOf(item.data));
+                    StringTag potion = new StringTag("Potion", "minecraft:" + name);
+                    tag.put(potion);
+                }
+                item.tag = tag;
+                item.data = 0;
+            }
+        }
+    }
+
+    public static ItemStack readItemStack(ByteBuf input) throws IOException {
+        short id = input.readShort();
+        if (id < 0) {
+
+            return null;
+        } else {
+            ItemStack item = new ItemStack();
+            item.id = id;
+            item.amount = input.readByte();
+            item.data = input.readShort();
+            item.tag = PacketUtil.readNBT(input);
+            return item;
+        }
+    }
+
+    public static void writeItemStack(ItemStack item, ByteBuf output) throws IOException {
+        if (item == null) {
+            output.writeShort(-1);
+        } else {
+            output.writeShort(item.id);
+            output.writeByte(item.amount);
+            output.writeShort(item.data);
+            PacketUtil.writeNBT(output, item.tag);
+        }
+    }
+
+    public static class ItemStack {
+
+        public short id;
+        public byte amount;
+        public short data;
+        public CompoundTag tag;
+
+        public static ItemStack fromBukkit(org.bukkit.inventory.ItemStack stack) {
+            ItemStack item = new ItemStack();
+            item.id = (short) stack.getTypeId();
+            item.amount = (byte) stack.getAmount();
+            item.data = stack.getData().getData();
+            // TODO: nbt
+            return item;
+        }
+    }
+
+    private static Map<String, Integer> ENTTIY_NAME_TO_ID = new HashMap<>();
+    private static Map<Integer, String> ENTTIY_ID_TO_NAME = new HashMap<>();
+
+    private static Map<String, Integer> POTION_NAME_TO_ID = new HashMap<>();
+    private static Map<Integer, String> POTION_ID_TO_NAME = new HashMap<>();
+
+    static {
+        /* Entities */
+        registerEntity(1, "Item");
+        registerEntity(2, "XPOrb");
+        registerEntity(7, "ThrownEgg");
+        registerEntity(8, "LeashKnot");
+        registerEntity(9, "Painting");
+        registerEntity(10, "Arrow");
+        registerEntity(11, "Snowball");
+        registerEntity(12, "Fireball");
+        registerEntity(13, "SmallFireball");
+        registerEntity(14, "ThrownEnderpearl");
+        registerEntity(15, "EyeOfEnderSignal");
+        registerEntity(16, "ThrownPotion");
+        registerEntity(17, "ThrownExpBottle");
+        registerEntity(18, "ItemFrame");
+        registerEntity(19, "WitherSkull");
+        registerEntity(20, "PrimedTnt");
+        registerEntity(21, "FallingSand");
+        registerEntity(22, "FireworksRocketEntity");
+        registerEntity(30, "ArmorStand");
+        registerEntity(40, "MinecartCommandBlock");
+        registerEntity(41, "Boat");
+        registerEntity(42, "MinecartRideable");
+        registerEntity(43, "MinecartChest");
+        registerEntity(44, "MinecartFurnace");
+        registerEntity(45, "MinecartTNT");
+        registerEntity(46, "MinecartHopper");
+        registerEntity(47, "MinecartSpawner");
+        registerEntity(48, "Mob");
+        registerEntity(49, "Monster");
+        registerEntity(50, "Creeper");
+        registerEntity(51, "Skeleton");
+        registerEntity(52, "Spider");
+        registerEntity(53, "Giant");
+        registerEntity(54, "Zombie");
+        registerEntity(55, "Slime");
+        registerEntity(56, "Ghast");
+        registerEntity(57, "PigZombie");
+        registerEntity(58, "Enderman");
+        registerEntity(59, "CaveSpider");
+        registerEntity(60, "Silverfish");
+        registerEntity(61, "Blaze");
+        registerEntity(62, "LavaSlime");
+        registerEntity(63, "EnderDragon");
+        registerEntity(64, "WitherBoss");
+        registerEntity(65, "Bat");
+        registerEntity(66, "Witch");
+        registerEntity(67, "Endermite");
+        registerEntity(68, "Guardian");
+        registerEntity(90, "Pig");
+        registerEntity(91, "Sheep");
+        registerEntity(92, "Cow");
+        registerEntity(93, "Chicken");
+        registerEntity(94, "Squid");
+        registerEntity(95, "Wolf");
+        registerEntity(96, "MushroomCow");
+        registerEntity(97, "SnowMan");
+        registerEntity(98, "Ozelot");
+        registerEntity(99, "VillagerGolem");
+        registerEntity(100, "EntityHorse");
+        registerEntity(101, "Rabbit");
+        registerEntity(120, "Villager");
+        registerEntity(200, "EnderCrystal");
+
+        /* Potions */
+        registerPotion(0, "water");
+        registerPotion(64, "mundane");
+        registerPotion(32, "thick");
+        registerPotion(16, "awkward");
+
+        registerPotion(8198, "night_vision");
+        registerPotion(8262, "long_night_vision");
+
+        registerPotion(8206, "invisibility");
+        registerPotion(8270, "long_invisibility");
+
+        registerPotion(8203, "leaping");
+        registerPotion(8267, "long_leaping");
+        registerPotion(8235, "strong_leaping");
+
+        registerPotion(8195, "fire_resistance");
+        registerPotion(8259, "long_fire_resistance");
+
+        registerPotion(8194, "swiftness");
+        registerPotion(8258, "long_swiftness");
+        registerPotion(8226, "strong_swiftness");
+
+        registerPotion(8202, "slowness");
+        registerPotion(8266, "long_slowness");
+
+        registerPotion(8205, "water_breathing");
+        registerPotion(8269, "long_water_breathing");
+
+        registerPotion(8197, "healing");
+        registerPotion(8229, "strong_healing");
+
+        registerPotion(8204, "harming");
+        registerPotion(8236, "strong_harming");
+
+        registerPotion(8196, "poison");
+        registerPotion(8260, "long_poison");
+        registerPotion(8228, "strong_poison");
+
+        registerPotion(8193, "regeneration");
+        registerPotion(8257, "long_regeneration");
+        registerPotion(8225, "strong_regeneration");
+
+        registerPotion(8201, "strength");
+        registerPotion(8265, "long_strength");
+        registerPotion(8233, "strong_strength");
+
+        registerPotion(8200, "weakness");
+        registerPotion(8264, "long_weakness");
+
+    }
+
+    private static void registerEntity(Integer id, String name) {
+        ENTTIY_ID_TO_NAME.put(id, name);
+        ENTTIY_NAME_TO_ID.put(name, id);
+    }
+
+    private static void registerPotion(Integer id, String name) {
+        POTION_ID_TO_NAME.put(id, name);
+        POTION_NAME_TO_ID.put(name, id);
+    }
+}

src/main/java/us/myles/ViaVersion/sounds/SoundEffect.java

@@ -252,11 +252,13 @@ public enum SoundEffect {
     private String name;
     private String newname;
     private SoundCategory cat;
+    private boolean breaksound;
 
     SoundEffect(String name, String newname, SoundCategory cat) {
         this.cat = cat;
         this.newname = newname;
         this.name = name;
+        this.breaksound = name.startsWith("dig.");
     }
 
     public static SoundEffect getByName(String name) {
@@ -279,5 +281,9 @@ public enum SoundEffect {
     public SoundCategory getCategory() {
         return cat;
     }
+    
+    public boolean isBreakPlaceSound() {
+    	return breaksound;
+    }
 
 }

src/main/java/us/myles/ViaVersion/transformers/IncomingTransformer.java

@@ -1,17 +1,21 @@
 package us.myles.ViaVersion.transformers;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import org.bukkit.Material;
 import org.bukkit.inventory.ItemStack;
 import us.myles.ViaVersion.CancelException;
 import us.myles.ViaVersion.ConnectionInfo;
 import us.myles.ViaVersion.ViaVersionPlugin;
 import us.myles.ViaVersion.packets.PacketType;
 import us.myles.ViaVersion.packets.State;
+import us.myles.ViaVersion.slot.ItemSlotRewriter;
 import us.myles.ViaVersion.util.PacketUtil;
 import us.myles.ViaVersion.util.ReflectionUtil;
 
+import java.io.IOException;
+import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 
 public class IncomingTransformer {
     private final ConnectionInfo info;
@@ -82,7 +86,7 @@ public class IncomingTransformer {
             return;
         }
         if (packet == PacketType.PLAY_PLAYER_DIGGING) {
-            byte status = input.readByte();
+            int status = input.readByte() & 0xFF; // unsign
             if (status == 6) { // item swap
                 throw new CancelException();
             }
@@ -99,10 +103,13 @@ public class IncomingTransformer {
             byte button = input.readByte();
             short action = input.readShort();
             byte mode = input.readByte();
+            // if the action is on an elytra armour slot
             if (slot == 45 && windowID == 0) {
                 try {
                     Class<?> setSlot = ReflectionUtil.nms("PacketPlayOutSetSlot");
-                    Object setSlotPacket = setSlot.getConstructors()[1].newInstance(windowID, slot, null);
+                    Constructor setSlotConstruct = setSlot.getDeclaredConstructor(int.class, int.class, ReflectionUtil.nms("ItemStack"));
+                    // properly construct
+                    Object setSlotPacket = setSlotConstruct.newInstance(windowID, slot, null);
                     info.getChannel().pipeline().writeAndFlush(setSlotPacket); // slot is empty
                     slot = -999; // we're evil, they'll throw item on the ground
                 } catch (ClassNotFoundException e) {
@@ -113,6 +120,8 @@ public class IncomingTransformer {
                     e.printStackTrace();
                 } catch (InvocationTargetException e) {
                     e.printStackTrace();
+                } catch (NoSuchMethodException e) {
+                    e.printStackTrace();
                 }
 
             }
@@ -121,7 +130,7 @@ public class IncomingTransformer {
             output.writeByte(button);
             output.writeShort(action);
             output.writeByte(mode);
-            output.writeBytes(input);
+            ItemSlotRewriter.rewrite1_9To1_8(input, output);
             return;
         }
         if (packet == PacketType.PLAY_CLIENT_SETTINGS) {
@@ -166,6 +175,26 @@ public class IncomingTransformer {
             }
             return;
         }
+        if(packet == PacketType.PLAY_PLUGIN_MESSAGE_REQUEST) {
+            String name = PacketUtil.readString(input);
+            PacketUtil.writeString(name, output);
+            byte[] b = new byte[input.readableBytes()];
+            input.readBytes(b);
+            // patch books
+            if(name.equals("MC|BSign")){
+                ByteBuf in = Unpooled.wrappedBuffer(b);
+                try {
+                    ItemSlotRewriter.ItemStack stack = ItemSlotRewriter.readItemStack(in);
+                    stack.id = (short) Material.WRITTEN_BOOK.getId();
+                    // write
+                    ItemSlotRewriter.writeItemStack(stack, output);
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+                return;
+            }
+            output.writeBytes(b);
+        }
         if (packet == PacketType.PLAY_PLAYER_BLOCK_PLACEMENT) {
             Long position = input.readLong();
             output.writeLong(position);
@@ -174,22 +203,14 @@ public class IncomingTransformer {
             int hand = PacketUtil.readVarInt(input);
 
             ItemStack inHand = ViaVersionPlugin.getHandItem(info);
-            Object item = null;
             try {
-                Method m = ReflectionUtil.obc("inventory.CraftItemStack").getDeclaredMethod("asNMSCopy", ItemStack.class);
-                item = m.invoke(null, inHand);
-            } catch (NoSuchMethodException e) {
-                e.printStackTrace();
-            } catch (ClassNotFoundException e) {
-                e.printStackTrace();
-            } catch (InvocationTargetException e) {
-                e.printStackTrace();
-            } catch (IllegalAccessException e) {
+                ItemSlotRewriter.ItemStack item = ItemSlotRewriter.ItemStack.fromBukkit(inHand);
+                ItemSlotRewriter.fixIdsFrom1_9To1_8(item);
+                ItemSlotRewriter.writeItemStack(item, output);
+            } catch (Exception e) {
                 e.printStackTrace();
             }
 
-            PacketUtil.writeItem(item, output);
-
             short curX = input.readUnsignedByte();
             output.writeByte(curX);
             short curY = input.readUnsignedByte();
@@ -206,26 +227,25 @@ public class IncomingTransformer {
             output.writeByte(255);
             // write item in hand
             ItemStack inHand = ViaVersionPlugin.getHandItem(info);
-            Object item = null;
             try {
-                Method m = ReflectionUtil.obc("inventory.CraftItemStack").getDeclaredMethod("asNMSCopy", ItemStack.class);
-                item = m.invoke(null, inHand);
-            } catch (NoSuchMethodException e) {
-                e.printStackTrace();
-            } catch (ClassNotFoundException e) {
-                e.printStackTrace();
-            } catch (InvocationTargetException e) {
-                e.printStackTrace();
-            } catch (IllegalAccessException e) {
+                ItemSlotRewriter.ItemStack item = ItemSlotRewriter.ItemStack.fromBukkit(inHand);
+                ItemSlotRewriter.fixIdsFrom1_9To1_8(item);
+                ItemSlotRewriter.writeItemStack(item, output);
+            } catch (Exception e) {
                 e.printStackTrace();
             }
-            PacketUtil.writeItem(item, output);
 
             output.writeByte(-1);
             output.writeByte(-1);
             output.writeByte(-1);
             return;
         }
+        if (packet == PacketType.PLAY_CREATIVE_INVENTORY_ACTION) {
+            short slot = input.readShort();
+            output.writeShort(slot);
+
+            ItemSlotRewriter.rewrite1_9To1_8(input, output);
+        }
         output.writeBytes(input);
     }
 }

src/main/java/us/myles/ViaVersion/transformers/OutgoingTransformer.java

@@ -1,38 +1,38 @@
 package us.myles.ViaVersion.transformers;
 
-import com.google.gson.Gson;
-import com.google.gson.JsonObject;
 import io.netty.buffer.ByteBuf;
 import org.bukkit.entity.EntityType;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
 import org.spacehq.mc.protocol.data.game.chunk.Column;
 import org.spacehq.mc.protocol.util.NetUtil;
 import us.myles.ViaVersion.CancelException;
 import us.myles.ViaVersion.ConnectionInfo;
 import us.myles.ViaVersion.ViaVersionPlugin;
 import us.myles.ViaVersion.api.ViaVersion;
-import us.myles.ViaVersion.metadata.MetaIndex;
-import us.myles.ViaVersion.metadata.NewType;
-import us.myles.ViaVersion.metadata.Type;
+import us.myles.ViaVersion.metadata.MetadataRewriter;
 import us.myles.ViaVersion.packets.PacketType;
 import us.myles.ViaVersion.packets.State;
+import us.myles.ViaVersion.slot.ItemSlotRewriter;
 import us.myles.ViaVersion.sounds.SoundEffect;
 import us.myles.ViaVersion.util.EntityUtil;
 import us.myles.ViaVersion.util.PacketUtil;
 import us.myles.ViaVersion.util.ReflectionUtil;
 
 import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
 import java.util.*;
 
 import static us.myles.ViaVersion.util.PacketUtil.*;
 
 public class OutgoingTransformer {
-    private static Gson gson = new Gson();
     private final ConnectionInfo info;
     private final ViaVersionPlugin plugin = (ViaVersionPlugin) ViaVersion.getInstance();
     private boolean cancel = false;
+
     private Map<Integer, UUID> uuidMap = new HashMap<Integer, UUID>();
     private Map<Integer, EntityType> clientEntityTypes = new HashMap<Integer, EntityType>();
+    private Map<Integer, Integer> vehicleMap = new HashMap<>();
 
     public OutgoingTransformer(ConnectionInfo info) {
         this.info = info;
@@ -48,7 +48,7 @@ public class OutgoingTransformer {
         if (packet == null) {
             throw new RuntimeException("Outgoing Packet not found? " + packetID + " State: " + info.getState() + " Version: " + info.getProtocol());
         }
-//        if (packet != PacketType.PLAY_CHUNK_DATA && packet != PacketType.PLAY_KEEP_ALIVE && packet != PacketType.PLAY_TIME_UPDATE && (!packet.name().toLowerCase().contains("move") && !packet.name().contains("look")))
+//        if (packet != PacketType.PLAY_CHUNK_DATA && packet != PacketType.PLAY_KEEP_ALIVE && packet != PacketType.PLAY_TIME_UPDATE && (!packet.name().toLowerCase().contains("move") && !packet.name().toLowerCase().contains("look")))
 //            System.out.println("Packet Type: " + packet + " Original ID: " + packetID + " State:" + info.getState());
         if (packet.getPacketID() != -1) {
             packetID = packet.getNewPacketID();
@@ -58,10 +58,14 @@ public class OutgoingTransformer {
         PacketUtil.writeVarInt(packetID, output);
         if (packet == PacketType.PLAY_NAMED_SOUND_EFFECT) {
             String name = PacketUtil.readString(input);
+
             SoundEffect effect = SoundEffect.getByName(name);
             int catid = 0;
             String newname = name;
             if (effect != null) {
+                if (effect.isBreakPlaceSound()) {
+                    throw new CancelException();
+                }
                 catid = effect.getCategory().getId();
                 newname = effect.getNewName();
             }
@@ -76,14 +80,34 @@ public class OutgoingTransformer {
             if (!lead) {
                 output.clear();
                 writeVarInt(PacketType.PLAY_SET_PASSENGERS.getNewPacketID(), output);
-                writeVarInt(vehicle, output);
-                writeVarIntArray(Collections.singletonList(passenger), output);
+                if (vehicle == -1) {
+                    if (!vehicleMap.containsKey(passenger))
+                        throw new CancelException();
+                    vehicle = vehicleMap.remove(passenger);
+                    writeVarInt(vehicle, output);
+                    writeVarIntArray(Collections.<Integer>emptyList(), output);
+                } else {
+                    writeVarInt(vehicle, output);
+                    writeVarIntArray(Collections.singletonList(passenger), output);
+                    vehicleMap.put(passenger, vehicle);
+                }
                 return;
             }
             output.writeInt(passenger);
             output.writeInt(vehicle);
             return;
         }
+        if (packet == PacketType.PLAY_PLUGIN_MESSAGE) {
+            String name = PacketUtil.readString(input);
+            PacketUtil.writeString(name, output);
+            byte[] b = new byte[input.readableBytes()];
+            input.readBytes(b);
+            // patch books
+            if (name.equals("MC|BOpen")) {
+                PacketUtil.writeVarInt(0, output);
+            }
+            output.writeBytes(b);
+        }
         if (packet == PacketType.PLAY_DISCONNECT) {
             String reason = readString(input);
             writeString(fixJson(reason), output);
@@ -99,6 +123,55 @@ public class OutgoingTransformer {
             output.writeBytes(input);
             return;
         }
+        if (packet == PacketType.PLAY_PLAYER_LIST_ITEM) {
+            int action = readVarInt(input);
+            writeVarInt(action, output);
+            int players = readVarInt(input);
+            writeVarInt(players, output);
+
+            // loop through players
+            for (int i = 0; i < players; i++) {
+                UUID uuid = readUUID(input);
+                writeUUID(uuid, output);
+                if (action == 0) { // add player
+                    writeString(readString(input), output); // name
+
+                    int properties = readVarInt(input);
+                    writeVarInt(properties, output);
+
+                    // loop through properties
+                    for (int j = 0; j < properties; j++) {
+                        writeString(readString(input), output); // name
+                        writeString(readString(input), output); // value
+                        boolean isSigned = input.readBoolean();
+                        output.writeBoolean(isSigned);
+                        if (isSigned) {
+                            writeString(readString(input), output); // signature
+                        }
+                    }
+
+                    writeVarInt(readVarInt(input), output); // gamemode
+                    writeVarInt(readVarInt(input), output); // ping
+                    boolean hasDisplayName = input.readBoolean();
+                    output.writeBoolean(hasDisplayName);
+                    if (hasDisplayName) {
+                        writeString(fixJson(readString(input)), output); // display name
+                    }
+                } else if ((action == 1) || (action == 2)) { // update gamemode || update latency
+                    writeVarInt(readVarInt(input), output);
+                } else if (action == 3) { // update display name
+                    boolean hasDisplayName = input.readBoolean();
+                    output.writeBoolean(hasDisplayName);
+                    if (hasDisplayName) {
+                        writeString(fixJson(readString(input)), output); // display name
+                    }
+                } else if (action == 4) { // remove player
+                    // no fields
+                }
+            }
+
+            return;
+        }
         if (packet == PacketType.PLAY_PLAYER_LIST_HEADER_FOOTER) {
             String header = readString(input);
             String footer = readString(input);
@@ -176,9 +249,14 @@ public class OutgoingTransformer {
 
         if (packet == PacketType.STATUS_RESPONSE) {
             String original = PacketUtil.readString(input);
-            JsonObject object = gson.fromJson(original, JsonObject.class);
-            object.get("version").getAsJsonObject().addProperty("protocol", info.getProtocol());
-            PacketUtil.writeString(gson.toJson(object), output);
+            try {
+                JSONObject json = (JSONObject) new JSONParser().parse(original);
+                JSONObject version = (JSONObject) json.get("version");
+                version.put("protocol", info.getProtocol());
+                PacketUtil.writeString(json.toJSONString(), output);
+            } catch (ParseException e) {
+                e.printStackTrace();
+            }
             return;
         }
         if (packet == PacketType.LOGIN_SUCCESS) {
@@ -186,7 +264,7 @@ public class OutgoingTransformer {
             PacketUtil.writeString(uu, output);
             UUID uniqueId = UUID.fromString(uu);
             info.setUUID(uniqueId);
-            plugin.setPorted(uniqueId, true);
+            plugin.addPortedClient(info);
             output.writeBytes(input);
             return;
         }
@@ -205,21 +283,15 @@ public class OutgoingTransformer {
                 slot += 1; // add 1 so it's now 2-5
             }
             PacketUtil.writeVarInt(slot, output);
-            output.writeBytes(input);
+
+            ItemSlotRewriter.rewrite1_8To1_9(input, output);
+            return;
         }
         if (packet == PacketType.PLAY_ENTITY_METADATA) {
             int id = PacketUtil.readVarInt(input);
             PacketUtil.writeVarInt(id, output);
 
-            try {
-                List dw = ReflectionUtil.get(info.getLastPacket(), "b", List.class);
-                // get entity via entityID, not preferred but we need it.
-                transformMetadata(id, dw, output);
-            } catch (NoSuchFieldException e) {
-                e.printStackTrace();
-            } catch (IllegalAccessException e) {
-                e.printStackTrace();
-            }
+            transformMetadata(id, input, output);
             return;
         }
 
@@ -330,6 +402,27 @@ public class OutgoingTransformer {
             output.writeBytes(input);
             return;
         }
+        if (packet == PacketType.PLAY_SET_SLOT) {
+            int windowId = input.readUnsignedByte();
+            output.writeByte(windowId);
+
+            short slot = input.readShort();
+            output.writeShort(slot);
+            ItemSlotRewriter.rewrite1_8To1_9(input, output);
+            return;
+        }
+        if (packet == PacketType.PLAY_WINDOW_ITEMS) {
+            int windowId = input.readUnsignedByte();
+            output.writeByte(windowId);
+
+            short count = input.readShort();
+            output.writeShort(count);
+
+            for (int i = 0; i < count; i++) {
+                ItemSlotRewriter.rewrite1_8To1_9(input, output);
+            }
+            return;
+        }
         if (packet == PacketType.PLAY_SPAWN_MOB) {
             int id = PacketUtil.readVarInt(input);
             PacketUtil.writeVarInt(id, output);
@@ -358,16 +451,8 @@ public class OutgoingTransformer {
             output.writeShort(vY);
             short vZ = input.readShort();
             output.writeShort(vZ);
-            try {
-                Object dataWatcher = ReflectionUtil.get(info.getLastPacket(), "l", ReflectionUtil.nms("DataWatcher"));
-                transformMetadata(id, dataWatcher, output);
-            } catch (NoSuchFieldException e) {
-                e.printStackTrace();
-            } catch (IllegalAccessException e) {
-                e.printStackTrace();
-            } catch (ClassNotFoundException e) {
-                e.printStackTrace();
-            }
+
+            transformMetadata(id, input, output);
             return;
         }
         if (packet == PacketType.PLAY_UPDATE_SIGN) {
@@ -411,16 +496,11 @@ public class OutgoingTransformer {
             output.writeByte(pitch);
             byte yaw = input.readByte();
             output.writeByte(yaw);
-            try {
-                Object dataWatcher = ReflectionUtil.get(info.getLastPacket(), "i", ReflectionUtil.nms("DataWatcher"));
-                transformMetadata(id, dataWatcher, output);
-            } catch (NoSuchFieldException e) {
-                e.printStackTrace();
-            } catch (IllegalAccessException e) {
-                e.printStackTrace();
-            } catch (ClassNotFoundException e) {
-                e.printStackTrace();
-            }
+
+            // next field is Current Item, this was removed in 1.9 so we'll ignore it
+            input.readShort();
+
+            transformMetadata(id, input, output);
 
             return;
         }
@@ -433,6 +513,20 @@ public class OutgoingTransformer {
             output.writeBytes(input);
             return;
         }
+        if (packet == PacketType.PLAY_ENTITY_EFFECT) {
+            int id = PacketUtil.readVarInt(input);
+            PacketUtil.writeVarInt(id, output);
+            byte effectID = input.readByte();
+            output.writeByte(effectID);
+            byte amplifier = input.readByte();
+            output.writeByte(amplifier);
+            int duration = PacketUtil.readVarInt(input);
+            PacketUtil.writeVarInt(duration, output);
+            // we need to write as a byte instead of boolean
+            boolean hideParticles = input.readBoolean();
+            output.writeByte(hideParticles ? 1 : 0);
+            return;
+        }
         if (packet == PacketType.PLAY_TEAM) {
             String teamName = PacketUtil.readString(input);
             PacketUtil.writeString(teamName, output);
@@ -464,18 +558,18 @@ public class OutgoingTransformer {
             output.writeBoolean(groundUp);
 
             int bitMask = input.readUnsignedShort();
-
-            if (bitMask == 0) {
-                output.clear();
-                PacketUtil.writeVarInt(PacketType.PLAY_UNLOAD_CHUNK.getNewPacketID(), output);
-                output.writeInt(chunkX);
-                output.writeInt(chunkZ);
-                return;
-            }
             int size = PacketUtil.readVarInt(input);
-
             byte[] data = new byte[size];
             input.readBytes(data);
+//            if (bitMask == 0 && groundUp) {
+//                // if 256
+//                output.clear();
+//                PacketUtil.writeVarInt(PacketType.PLAY_UNLOAD_CHUNK.getNewPacketID(), output);
+//                output.writeInt(chunkX);
+//                output.writeInt(chunkZ);
+//                System.out.println("Sending unload chunk " + chunkX + " " + chunkZ + " - " + size + " bulk: " + bulk);
+//                return;
+//            }
             boolean sk = false;
             if (info.getLastPacket().getClass().getName().endsWith("PacketPlayOutMapChunkBulk")) {
                 try {
@@ -502,7 +596,7 @@ public class OutgoingTransformer {
         output.writeBytes(input);
     }
 
-    private String fixJson(String line) {
+    public static String fixJson(String line) {
         if (line == null || line.equalsIgnoreCase("null")) {
             line = "{\"text\":\"\"}";
         } else {
@@ -511,140 +605,24 @@ public class OutgoingTransformer {
             if (line.startsWith("\""))
                 line = "{\"text\":" + line + "}";
         }
+        try {
+            new JSONParser().parse(line);
+        } catch (Exception e) {
+            System.out.println("Invalid JSON String: \"" + line + "\" Please report this issue to the ViaVersion Github: " + e.getMessage());
+            return "{\"text\":\"\"}";
+        }
         return line;
     }
 
-    private void transformMetadata(int entityID, Object dw, ByteBuf output) throws CancelException {
-        // get entity
-        try {
-            transformMetadata(entityID, (List) ReflectionUtil.invoke(dw, "b"), output);
-        } catch (IllegalAccessException e) {
-            e.printStackTrace();
-        } catch (NoSuchMethodException e) {
-            e.printStackTrace();
-        } catch (InvocationTargetException e) {
-            e.printStackTrace();
-        }
-    }
-
-    private void transformMetadata(int entityID, List dw, ByteBuf output) throws CancelException {
+    private void transformMetadata(int entityID, ByteBuf input, ByteBuf output) throws CancelException {
         EntityType type = clientEntityTypes.get(entityID);
         if (type == null) {
             System.out.println("Unable to get entity for ID: " + entityID);
             output.writeByte(255);
             return;
         }
-        if (dw != null) {
-            short id = -1;
-            int data = -1;
-
-            Iterator iterator = dw.iterator();
-            while (iterator.hasNext()) {
-                Object watchableObj = iterator.next(); //
-                MetaIndex metaIndex = null;
-                try {
-                    metaIndex = MetaIndex.getIndex(type, (int) ReflectionUtil.invoke(watchableObj, "a"));
-                } catch (NoSuchMethodException e) {
-                    e.printStackTrace();
-                } catch (InvocationTargetException e) {
-                    e.printStackTrace();
-                } catch (IllegalAccessException e) {
-                    e.printStackTrace();
-                }
-                try {
-                    if (metaIndex.getNewType() != NewType.Discontinued) {
-                        if (metaIndex.getNewType() != NewType.BlockID || id != -1 && data == -1 || id == -1 && data != -1) { // block ID is only written if we have both parts
-                            output.writeByte(metaIndex.getNewIndex());
-                            output.writeByte(metaIndex.getNewType().getTypeID());
-                        }
-                        Object value = ReflectionUtil.invoke(watchableObj, "b");
-                        switch (metaIndex.getNewType()) {
-                            case Byte:
-                                // convert from int, byte
-                                if (metaIndex.getOldType() == Type.Byte) {
-                                    output.writeByte(((Byte) value).byteValue());
-                                }
-                                if (metaIndex.getOldType() == Type.Int) {
-                                    output.writeByte(((Integer) value).byteValue());
-                                }
-                                break;
-                            case OptUUID:
-                                String owner = (String) value;
-                                UUID toWrite = null;
-                                if (owner.length() != 0) {
-                                    try {
-                                        toWrite = UUID.fromString(owner);
-                                    } catch (Exception ignored) {
-                                    }
-                                }
-                                output.writeBoolean(toWrite != null);
-                                if (toWrite != null)
-                                    PacketUtil.writeUUID((UUID) toWrite, output);
-                                break;
-                            case BlockID:
-                                // if we have both sources :))
-                                if (metaIndex.getOldType() == Type.Byte) {
-                                    data = ((Byte) value).byteValue();
-                                }
-                                if (metaIndex.getOldType() == Type.Short) {
-                                    id = ((Short) value).shortValue();
-                                }
-                                if (id != -1 && data != -1) {
-                                    int combined = id << 4 | data;
-                                    data = -1;
-                                    id = -1;
-                                    PacketUtil.writeVarInt(combined, output);
-                                }
-                                break;
-                            case VarInt:
-                                // convert from int, short, byte
-                                if (metaIndex.getOldType() == Type.Byte) {
-                                    PacketUtil.writeVarInt(((Byte) value).intValue(), output);
-                                }
-                                if (metaIndex.getOldType() == Type.Short) {
-                                    PacketUtil.writeVarInt(((Short) value).intValue(), output);
-                                }
-                                if (metaIndex.getOldType() == Type.Int) {
-                                    PacketUtil.writeVarInt(((Integer) value).intValue(), output);
-                                }
-                                break;
-                            case Float:
-                                output.writeFloat(((Float) value).floatValue());
-                                break;
-                            case String:
-                                PacketUtil.writeString((String) value, output);
-                                break;
-                            case Boolean:
-                                output.writeBoolean(((Byte) value).byteValue() != 0);
-                                break;
-                            case Slot:
-                                PacketUtil.writeItem(value, output);
-                                break;
-                            case Position:
-                                output.writeInt((int) ReflectionUtil.invoke(value, "getX"));
-                                output.writeInt((int) ReflectionUtil.invoke(value, "getY"));
-                                output.writeInt((int) ReflectionUtil.invoke(value, "getZ"));
-                                break;
-                            case Vector3F:
-                                output.writeFloat((float) ReflectionUtil.invoke(value, "getX"));
-                                output.writeFloat((float) ReflectionUtil.invoke(value, "getY"));
-                                output.writeFloat((float) ReflectionUtil.invoke(value, "getZ"));
-                        }
-
-                    }
-                } catch (Exception e) {
-                    if (type != null) {
-                        System.out.println("An error occurred with entity meta data for " + type);
-                        System.out.println("Old ID: " + metaIndex.getIndex() + " New ID: " + metaIndex.getNewIndex());
-                        System.out.println("Old Type: " + metaIndex.getOldType() + " New Type: " + metaIndex.getNewType());
-                    }
-                    e.printStackTrace();
-                }
-            }
-        }
-        output.writeByte(255);
-
-
+        List<MetadataRewriter.Entry> list = MetadataRewriter.readMetadata1_8(type, input);
+        MetadataRewriter.writeMetadata1_9(type, list, output);
     }
 
 

src/main/java/us/myles/ViaVersion/util/PacketUtil.java

@@ -3,6 +3,8 @@ package us.myles.ViaVersion.util;
 import com.google.common.base.Charsets;
 import com.google.common.base.Preconditions;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufInputStream;
+import io.netty.buffer.ByteBufOutputStream;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.handler.codec.MessageToByteEncoder;
@@ -11,6 +13,9 @@ import us.myles.ViaVersion.chunks.PacketChunk;
 import us.myles.ViaVersion.chunks.PacketChunkData;
 
 import java.io.ByteArrayOutputStream;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.nio.ByteBuffer;
@@ -21,6 +26,9 @@ import java.util.BitSet;
 import java.util.List;
 import java.util.UUID;
 
+import org.spacehq.opennbt.NBTIO;
+import org.spacehq.opennbt.tag.builtin.CompoundTag;
+
 public class PacketUtil {
     private static Method DECODE_METHOD;
     private static Method ENCODE_METHOD;
@@ -42,6 +50,25 @@ public class PacketUtil {
         }
     }
 
+    public static CompoundTag readNBT(ByteBuf input) throws IOException {
+        int readerIndex = input.readerIndex();
+        byte b = input.readByte();
+        if (b == 0) {
+            return null;
+        } else {
+            input.readerIndex(readerIndex);
+            return (CompoundTag) NBTIO.readTag(new DataInputStream(new ByteBufInputStream(input)));
+        }
+    }
+
+    public static void writeNBT(ByteBuf output, CompoundTag tag) throws IOException {
+        if (tag == null) {
+            output.writeByte(0);
+        } else {
+            NBTIO.writeTag(new DataOutputStream(new ByteBufOutputStream(output)), tag);
+        }
+    }
+
     public static List<Object> callDecode(ByteToMessageDecoder decoder, ChannelHandlerContext ctx, Object input) {
         List<Object> output = new ArrayList<Object>();
         try {
@@ -354,25 +381,6 @@ public class PacketUtil {
         return output;
     }
 
-    public static void writeItem(Object value, ByteBuf output) {
-        try {
-            Class<?> serializer = ReflectionUtil.nms("PacketDataSerializer");
-            Object init = serializer.getDeclaredConstructor(ByteBuf.class).newInstance(output);
-            Method toCall = init.getClass().getDeclaredMethod("a", ReflectionUtil.nms("ItemStack"));
-            toCall.invoke(init, value);
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
-        } catch (NoSuchMethodException e) {
-            e.printStackTrace();
-        } catch (InstantiationException e) {
-            e.printStackTrace();
-        } catch (IllegalAccessException e) {
-            e.printStackTrace();
-        } catch (InvocationTargetException e) {
-            e.printStackTrace();
-        }
-    }
-
     public static long[] readBlockPosition(ByteBuf buf) {
         long val = buf.readLong();
         long x = (val >> 38); // signed
@@ -394,4 +402,12 @@ public class PacketUtil {
 
         return data;
     }
+
+    public static boolean containsCause(Throwable t, Class<? extends Throwable> c) {
+        while (t != null) {
+            t = t.getCause();
+            if (c.isAssignableFrom(t.getClass())) return true;
+        }
+        return false;
+    }
 }

src/main/java/us/myles/ViaVersion/util/ReflectionUtil.java

@@ -27,6 +27,18 @@ public class ReflectionUtil {
         return m.invoke(o);
     }
 
+    public static <T> T getStatic(Class<?> clazz, String f, Class<T> t) throws NoSuchFieldException, IllegalAccessException {
+        Field field = clazz.getDeclaredField(f);
+        field.setAccessible(true);
+        return (T) field.get(null);
+    }
+
+    public static <T> T get(Object instance, Class<?> clazz, String f, Class<T> t) throws NoSuchFieldException, IllegalAccessException {
+        Field field = clazz.getDeclaredField(f);
+        field.setAccessible(true);
+        return (T) field.get(instance);
+    }
+
     public static <T> T get(Object o, String f, Class<T> t) throws NoSuchFieldException, IllegalAccessException {
         Field field = o.getClass().getDeclaredField(f);
         field.setAccessible(true);

src/main/resources/plugin.yml

@@ -1,6 +1,11 @@
 name: ViaVersion
 main: us.myles.ViaVersion.ViaVersionPlugin
 author: _MylesC
-version: 0.4.3
+version: ${version}
 load: startup
-loadbefore: [ProtocolLib, ProxyPipe]
+loadbefore: [ProtocolLib, ProxyPipe]
+commands:
+  viaversion:
+    description: Shows ViaVersion Version and more.
+    permission: viaversion.admin
+    aliases: [viaver]