Bug fixes and Networking

*Changed how datapack is synced S2C:

Before, sent raw NBT through network. Now:
1. converts NBT to SNBT;
2. uses Java's Deflater to compress the SNBT;
3. converts the compressed SNBT to byte array;
4. sends the byte array over network;
5. Reverses this using java's Inflater on the client.

This reduces the raw NBT network packet from aprox. 4KB to ~0.9KB. This was done in attempt to fix packet size issue with Velocity plugin, but also in general the player connection packet has the potential to get really massive really quickly depending on the datapack.

-Removed version checking between client and server. This was done in an attempt to make this compatible with Velocity plugin, which tends to get upset if we use regular Minecraft's connection packets.

*Changed MutableIntFlag to be implemented further up in the hierarchy (MutableWorldProperties). Added relevant casting checks. This is an attempt to fix bugs caused when other mods want to make 'dummy world properties' that don't respect the world properties hierarchy nor the client/server divide.

+Incremented version.

gradle.properties

@@ -4,7 +4,7 @@ minecraft_version=1.19.2
 yarn_mappings=1.19.2+build.28
 loader_version=0.14.10
 
-mod_version = 1.4.0
+mod_version = 1.4.1
 maven_group = com.github.clevernucleus
 archives_base_name = dataattributes
 

src/main/java/com/github/clevernucleus/dataattributes/DataAttributes.java

@@ -24,12 +24,10 @@
 import net.minecraft.entity.attribute.EntityAttribute;
 import net.minecraft.entity.attribute.EntityAttributeModifier;
 import net.minecraft.entity.attribute.EntityAttributes;
-import net.minecraft.nbt.NbtCompound;
 import net.minecraft.network.PacketByteBuf;
 import net.minecraft.resource.ResourceType;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.network.ServerLoginNetworkHandler;
-import net.minecraft.text.Text;
 import net.minecraft.util.Identifier;
 
 public class DataAttributes implements ModInitializer {
@@ -42,22 +40,13 @@ public class DataAttributes implements ModInitializer {
 
 	private static void loginQueryStart(ServerLoginNetworkHandler handler, MinecraftServer server, PacketSender sender, ServerLoginNetworking.LoginSynchronizer synchronizer) {
 		PacketByteBuf buf = PacketByteBufs.create();
-		NbtCompound tag = new NbtCompound();
-		DataAttributes.MANAGER.toNbt(tag);
-		buf.writeNbt(tag);
+		final byte[] bytes = DataAttributes.MANAGER.getCurrentData();
+		buf.writeByteArray(bytes);
 		sender.sendPacket(HANDSHAKE, buf);
 	}
 
 	private static void loginQueryResponse(MinecraftServer server, ServerLoginNetworkHandler handler, boolean understood, PacketByteBuf buf, LoginSynchronizer synchronizer, PacketSender responseSender) {
-		if(understood) {
-			byte[] verClient = buf.readByteArray();
-
-			if(verClient[0] != DataAttributes.semVer[0] || verClient[1] != DataAttributes.semVer[1]) {
-				handler.disconnect(Text.literal("Disconnected: version mismatch. Client has version " + verClient + ". Server has version " + DataAttributes.version + "."));
-			}
-		} else {
-			handler.disconnect(Text.literal("Disconnected: network communication issue."));
-		}
+		// Does doing nothing here make us compatible with Velocity plugin?
 	}
 
 	private static void refreshAttributes(final Entity entity) {

src/main/java/com/github/clevernucleus/dataattributes/DataAttributesClient.java

@@ -16,18 +16,15 @@
 import net.minecraft.client.network.ClientLoginNetworkHandler;
 import net.minecraft.client.network.ClientPlayNetworkHandler;
 import net.minecraft.client.world.ClientWorld;
-import net.minecraft.nbt.NbtCompound;
 import net.minecraft.network.PacketByteBuf;
 
 public class DataAttributesClient implements ClientModInitializer {
 	private static CompletableFuture<PacketByteBuf> loginQueryReceived(MinecraftClient client, ClientLoginNetworkHandler handler, PacketByteBuf buf, Consumer<GenericFutureListener<? extends Future<? super Void>>> listenerAdder) {
-		NbtCompound tag = buf.readNbt();
+final byte[] bytes = buf.readByteArray();
 
 		client.execute(() -> {
-			if(tag != null) {
-				DataAttributes.MANAGER.fromNbt(tag);
-				DataAttributes.MANAGER.apply();
-			}
+			DataAttributes.MANAGER.readFromData(bytes);
+			DataAttributes.MANAGER.apply();
 		});
 
 		PacketByteBuf bufOut = PacketByteBufs.create();
@@ -37,14 +34,12 @@ private static CompletableFuture<PacketByteBuf> loginQueryReceived(MinecraftClie
 	}
 
 	private static void updateReceived(MinecraftClient client, ClientPlayNetworkHandler handler, PacketByteBuf buf, PacketSender responseSender) {
-		NbtCompound tag = buf.readNbt();
+		final byte[] bytes = buf.readByteArray();
 		final int updateFlag = buf.readInt();
 
 		client.execute(() -> {
-			if(tag != null) {
-				DataAttributes.MANAGER.fromNbt(tag);
-				DataAttributes.MANAGER.apply();
-			}
+			DataAttributes.MANAGER.readFromData(bytes);
+			DataAttributes.MANAGER.apply();
 
 			ClientWorld world = client.world;
 

src/main/java/com/github/clevernucleus/dataattributes/impl/AttributeManager.java

@@ -3,12 +3,17 @@
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.Reader;
+import java.io.UnsupportedEncodingException;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executor;
 import java.util.stream.Collectors;
+import java.util.zip.DataFormatException;
+import java.util.zip.Deflater;
+import java.util.zip.Inflater;
 
 import org.slf4j.Logger;
 
@@ -23,6 +28,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
+import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import com.mojang.logging.LogUtils;
 
 import net.fabricmc.fabric.api.resource.SimpleResourceReloadListener;
@@ -32,6 +38,8 @@
 import net.minecraft.entity.attribute.DefaultAttributeRegistry;
 import net.minecraft.entity.attribute.EntityAttribute;
 import net.minecraft.nbt.NbtCompound;
+import net.minecraft.nbt.StringNbtReader;
+import net.minecraft.nbt.visitor.StringNbtWriter;
 import net.minecraft.resource.Resource;
 import net.minecraft.resource.ResourceManager;
 import net.minecraft.util.Identifier;
@@ -49,6 +57,7 @@ public final class AttributeManager implements SimpleResourceReloadListener<Attr
 	private Map<Identifier, EntityAttributeData> entityAttributeData = ImmutableMap.of();
 	private Map<Identifier, EntityTypeData> entityTypeData = ImmutableMap.of();
 	public Map<EntityType<? extends LivingEntity>, DefaultAttributeContainer> containers = ImmutableMap.of();
+	private byte[] currentData;
 
 	protected static class Wrapper {
 		public final Map<Identifier, EntityAttributeData> entityAttributeData;
@@ -248,11 +257,9 @@ private static void loadEntityTypes(ResourceManager manager, Map<Identifier, Ent
 		}
 	}
 
-	public DefaultAttributeContainer getContainer(EntityType<? extends LivingEntity> entityType) {
-		return this.containers.getOrDefault(entityType, DefaultAttributeRegistry.get(entityType));
-	}
-
-	public void toNbt(NbtCompound tag) {
+	private void generateCurrentData() {
+		StringNbtWriter writer = new StringNbtWriter();
+		NbtCompound nbt = new NbtCompound();
 		NbtCompound entityAttributeNbt = new NbtCompound();
 		NbtCompound entityTypeNbt = new NbtCompound();
 
@@ -268,14 +275,60 @@ public void toNbt(NbtCompound tag) {
 			entityTypeNbt.put(key.toString(), entry);
 		});
 
-		tag.put("Attributes", entityAttributeNbt);
-		tag.put("EntityTypes", entityTypeNbt);
+		nbt.put("Attributes", entityAttributeNbt);
+		nbt.put("EntityTypes", entityTypeNbt);
+
+		String snbt = writer.apply(nbt);
+		byte[] bytes;
+
+		try {
+			bytes = snbt.getBytes("UTF-8");
+		} catch (UnsupportedEncodingException e) {
+			bytes = new byte[] {(byte)0};
+		}
+
+		Deflater deflater = new Deflater();
+		deflater.setInput(bytes);
+		deflater.finish();
+
+		byte[] compressed = new byte[8192];
+		int size = deflater.deflate(compressed);
+		deflater.end();
+		this.currentData = Arrays.copyOf(compressed, size);
+	}
+
+	public byte[] getCurrentData() {
+		if(this.currentData == null) return new byte[] {(byte)0};
+		return this.currentData;
 	}
 
-	public void fromNbt(NbtCompound tag) {
-		if(tag.contains("Attributes")) {
+
+	public void readFromData(byte[] data) {
+		Inflater inflater = new Inflater();
+		inflater.setInput(data);
+
+		byte[] cache = new byte[8192];
+		int size;
+		try {
+			size = inflater.inflate(cache);
+		} catch (DataFormatException e) {
+			size = 1;
+		}
+
+		inflater.end();
+		byte[] uncompressed = Arrays.copyOf(cache, size);
+		String snbt = new String(uncompressed);
+		NbtCompound nbt;
+
+		try {
+			nbt = StringNbtReader.parse(snbt);
+		} catch (CommandSyntaxException e) {
+			nbt = new NbtCompound();
+		}
+
+		if(nbt.contains("Attributes")) {
 			ImmutableMap.Builder<Identifier, EntityAttributeData> builder = ImmutableMap.builder();
-			NbtCompound nbtCompound = tag.getCompound("Attributes");
+			NbtCompound nbtCompound = nbt.getCompound("Attributes");
 			nbtCompound.getKeys().forEach(key -> {
 				NbtCompound entry = nbtCompound.getCompound(key);
 				EntityAttributeData entityAttributeData = new EntityAttributeData();
@@ -286,9 +339,9 @@ public void fromNbt(NbtCompound tag) {
 			this.entityAttributeData = builder.build();
 		}
 
-		if(tag.contains("EntityTypes")) {
+		if(nbt.contains("EntityTypes")) {
 			ImmutableMap.Builder<Identifier, EntityTypeData> builder = ImmutableMap.builder();
-			NbtCompound nbtCompound = tag.getCompound("EntityTypes");
+			NbtCompound nbtCompound = nbt.getCompound("EntityTypes");
 			nbtCompound.getKeys().forEach(key -> {
 				NbtCompound entry = nbtCompound.getCompound(key);
 				EntityTypeData entityTypeData = new EntityTypeData();
@@ -300,6 +353,10 @@ public void fromNbt(NbtCompound tag) {
 		}
 	}
 
+	public DefaultAttributeContainer getContainer(EntityType<? extends LivingEntity> entityType) {
+		return this.containers.getOrDefault(entityType, DefaultAttributeRegistry.get(entityType));
+	}
+
 	public void apply() {
 		MutableRegistryImpl.unregister(Registry.ATTRIBUTE);
 
@@ -370,6 +427,7 @@ public CompletableFuture<Void> apply(AttributeManager.Wrapper data, ResourceMana
 			data.entityTypeData.forEach(entityTypeData::put);
 			this.entityTypeData = entityTypeData.build();
 
+			this.generateCurrentData();
 			this.apply();
 		}, executor);
 	}

src/main/java/com/github/clevernucleus/dataattributes/mixin/LevelPropertiesMixin.java

@@ -22,7 +22,7 @@
 import net.minecraft.world.level.storage.SaveVersionInfo;
 
 @Mixin(LevelProperties.class)
-abstract class LevelPropertiesMixin implements MutableIntFlag {
+abstract class LevelPropertiesMixin implements MutableWorldPropertiesMixin {
 
 	@Unique
 	private int data_updateFlag;

src/main/java/com/github/clevernucleus/dataattributes/mixin/LivingEntityMixin.java

@@ -16,6 +16,7 @@
 import net.minecraft.entity.LivingEntity;
 import net.minecraft.entity.attribute.AttributeContainer;
 import net.minecraft.world.World;
+import net.minecraft.world.WorldProperties;
 
 @Mixin(value = LivingEntity.class, priority = 999)
 abstract class LivingEntityMixin {
@@ -27,10 +28,16 @@ abstract class LivingEntityMixin {
 	@Unique
 	private int data_updateFlag;
 
+	private int data_checkedUpdateFlag(World world) {
+		WorldProperties worldProperties = world.getLevelProperties();
+		if(!(worldProperties instanceof MutableIntFlag)) return 0;
+		return ((MutableIntFlag)worldProperties).getUpdateFlag();
+	}
+
 	@Inject(method = "<init>", at = @At("TAIL"))
 	private void data_init(EntityType<? extends LivingEntity> entityType, World world, CallbackInfo ci) {
 		this.attributes = new AttributeContainer(DataAttributes.MANAGER.getContainer(entityType));
-		this.data_updateFlag = ((MutableIntFlag)world.getLevelProperties()).getUpdateFlag();
+		this.data_updateFlag = this.data_checkedUpdateFlag(world);
 		LivingEntity livingEntity = (LivingEntity)(Object)this;
 		((MutableAttributeContainer)livingEntity.getAttributes()).setLivingEntity(livingEntity);
 		livingEntity.setHealth(livingEntity.getMaxHealth());
@@ -39,7 +46,7 @@ private void data_init(EntityType<? extends LivingEntity> entityType, World worl
 	@Inject(method = "tick", at = @At(value = "INVOKE", target = "Lnet/minecraft/entity/LivingEntity;tickActiveItemStack()V"))
 	private void data_tick(CallbackInfo ci) {
 		LivingEntity livingEntity = (LivingEntity)(Object)this;
-		final int updateFlag = ((MutableIntFlag)livingEntity.world.getLevelProperties()).getUpdateFlag();
+		final int updateFlag = this.data_checkedUpdateFlag(livingEntity.world);
 
 		if(this.data_updateFlag != updateFlag) {
 			AttributeContainer container = livingEntity.getAttributes();

src/main/java/com/github/clevernucleus/dataattributes/mixin/MutableWorldPropertiesMixin.java

@@ -0,0 +1,10 @@
+package com.github.clevernucleus.dataattributes.mixin;
+
+import org.spongepowered.asm.mixin.Mixin;
+
+import com.github.clevernucleus.dataattributes.mutable.MutableIntFlag;
+
+import net.minecraft.world.MutableWorldProperties;
+
+@Mixin(MutableWorldProperties.class)
+public interface MutableWorldPropertiesMixin extends MutableIntFlag {}

src/main/java/com/github/clevernucleus/dataattributes/mixin/ReloadCommandMixin.java

@@ -14,7 +14,6 @@
 import net.fabricmc.fabric.api.networking.v1.PacketByteBufs;
 import net.fabricmc.fabric.api.networking.v1.PlayerLookup;
 import net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking;
-import net.minecraft.nbt.NbtCompound;
 import net.minecraft.network.PacketByteBuf;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.command.ReloadCommand;
@@ -41,9 +40,8 @@ private static void data_tryReloadDataPacks(Collection<String> dataPacks, Server
 			mutableUpdateFlag.setUpdateFlag(updateFlag2);
 
 			PacketByteBuf buf = PacketByteBufs.create();
-			NbtCompound tag = new NbtCompound();
-			DataAttributes.MANAGER.toNbt(tag);
-			buf.writeNbt(tag);
+			final byte[] bytes = DataAttributes.MANAGER.getCurrentData();
+			buf.writeByteArray(bytes);
 			buf.writeInt(mutableUpdateFlag.getUpdateFlag());
 			PlayerLookup.all(server).forEach(player -> ServerPlayNetworking.send(player, DataAttributes.RELOAD, buf));
 		}

src/main/java/com/github/clevernucleus/dataattributes/mixin/UnmodifiableLevelPropertiesMixin.java

@@ -10,7 +10,7 @@
 import net.minecraft.world.level.UnmodifiableLevelProperties;
 
 @Mixin(UnmodifiableLevelProperties.class)
-abstract class UnmodifiableLevelPropertiesMixin implements MutableIntFlag {
+abstract class UnmodifiableLevelPropertiesMixin implements MutableWorldPropertiesMixin {
 
 	@Final
 	@Shadow

src/main/java/com/github/clevernucleus/dataattributes/mixin/client/ClientWorldPropertiesMixin.java

@@ -3,12 +3,12 @@
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Unique;
 
-import com.github.clevernucleus.dataattributes.mutable.MutableIntFlag;
+import com.github.clevernucleus.dataattributes.mixin.MutableWorldPropertiesMixin;
 
 import net.minecraft.client.world.ClientWorld;
 
 @Mixin(ClientWorld.Properties.class)
-abstract class ClientWorldPropertiesMixin implements MutableIntFlag {
+abstract class ClientWorldPropertiesMixin implements MutableWorldPropertiesMixin {
 
 	@Unique
 	private int data_updateFlag;

src/main/java/com/github/clevernucleus/dataattributes/mutable/MutableIntFlag.java

@@ -1,6 +1,6 @@
 package com.github.clevernucleus.dataattributes.mutable;
 
 public interface MutableIntFlag {
-	void setUpdateFlag(int flag);
-	int getUpdateFlag();
+	default void setUpdateFlag(int flag) {}
+	default int getUpdateFlag() { return 0; }
 }

src/main/resources/dataattributes.mixins.json

@@ -15,6 +15,7 @@
         "PlayerEntityMixin",
         "MobEntityMixin",
         "ServerPlayerEntityMixin",
+        "MutableWorldPropertiesMixin",
         "LevelPropertiesMixin",
         "UnmodifiableLevelPropertiesMixin",
         "GameJoinS2CPacketMixin",