java.lang.IndexOutOfBoundsException when sending message via simpleimpl

[PlanetTeamSpeak]

I am trying to create a way to extend reach, I've managed to get it to work, but I would like to use packets to make it work on both the server and the client and to transmit other data in the future; however, whenever I try to send a packet when a PlayerInteractEvent.LeftClickAir event is fired, it throws an exception.

Edit: version is 1.12.2

Exception thrown:

io.netty.handler.codec.EncoderException: java.lang.IndexOutOfBoundsException: readerIndex(0) + length(4) exceeds writerIndex(1): UnpooledByteBufAllocator$InstrumentedUnpooledUnsafeHeapByteBuf(ridx: 0, widx: 1, cap: 256)
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:106)
	at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:801)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:814)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:794)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:831)
	at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1032)
	at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:296)
	at net.minecraftforge.fml.common.network.simpleimpl.SimpleNetworkWrapper.sendToServer(SimpleNetworkWrapper.java:321)
	at com.ptsmods.morecommands.miscellaneous.ClientEventHandler.onPlayerLeftClickAir(ClientEventHandler.java:78)
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_16_ClientEventHandler_onPlayerLeftClickAir_LeftClickEmpty.invoke(.dynamic)
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90)
	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182)
	at net.minecraftforge.common.ForgeHooks.onEmptyLeftClick(ForgeHooks.java:1135)
	at net.minecraft.client.Minecraft.clickMouse(Minecraft.java:1641)
	at net.minecraft.client.Minecraft.processKeyBinds(Minecraft.java:2375)
	at net.minecraft.client.Minecraft.runTickKeyboard(Minecraft.java:2146)
	at net.minecraft.client.Minecraft.runTick(Minecraft.java:1934)
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1187)
	at net.minecraft.client.Minecraft.run(Minecraft.java:441)
	at net.minecraft.client.main.Main.main(Main.java:118)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:97)
	at GradleStart.main(GradleStart.java:25)
Caused by: java.lang.IndexOutOfBoundsException: readerIndex(0) + length(4) exceeds writerIndex(1): UnpooledByteBufAllocator$InstrumentedUnpooledUnsafeHeapByteBuf(ridx: 0, widx: 1, cap: 256)
	at io.netty.buffer.AbstractByteBuf.checkReadableBytes0(AbstractByteBuf.java:1396)
	at io.netty.buffer.AbstractByteBuf.readInt(AbstractByteBuf.java:766)
	at net.minecraft.network.PacketBuffer.readInt(PacketBuffer.java:953)
	at com.ptsmods.morecommands.net.ClientLeftClickEventPacket.toBytes(ClientLeftClickEventPacket.java:59)
	at net.minecraftforge.fml.common.network.simpleimpl.SimpleIndexedCodec.encodeInto(SimpleIndexedCodec.java:30)
	at net.minecraftforge.fml.common.network.simpleimpl.SimpleIndexedCodec.encodeInto(SimpleIndexedCodec.java:26)
	at net.minecraftforge.fml.common.network.FMLIndexedMessageToMessageCodec.encode(FMLIndexedMessageToMessageCodec.java:81)
	at io.netty.handler.codec.MessageToMessageCodec$1.encode(MessageToMessageCodec.java:67)
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88)
	... 33 more

PlayerInteractEvent.LeftClickEmpty listener (ignore first line of the method, that's of another feature):

	@SubscribeEvent
	public void onPlayerLeftClickAir(PlayerInteractEvent.LeftClickEmpty event) throws CommandException {
		Reference.powerToolCommand(event.getEntityPlayer(), event.getHand(), event, true);
		int blockReachDistance = Reference.getBlockReach();
		Vec3d vec3d = event.getEntityPlayer().getPositionEyes(1F);
        Vec3d vec3d1 = event.getEntityPlayer().getLook(1F);
        Vec3d vec3d2 = vec3d.addVector(vec3d1.x * blockReachDistance, vec3d1.y * blockReachDistance, vec3d1.z * blockReachDistance);
        RayTraceResult result = event.getWorld().rayTraceBlocks(vec3d, vec3d2, false, false, true);
		BlockPos pos = result == null ? null : result.getBlockPos();
		result = Reference.getObjectMouseOver(blockReachDistance, 1F) == null ? result : Reference.getObjectMouseOver(blockReachDistance, 1F);
		Reference.print(LogType.INFO, pos, event.isCanceled(), event.getEntityPlayer().capabilities.isCreativeMode, FMLCommonHandler.instance().getSide(), blockReachDistance);
		if (pos != null && !event.isCanceled() && event.getEntityPlayer().capabilities.isCreativeMode);
			Reference.netWrapper.sendToServer(new ClientLeftClickEventPacket(result, event.getEntityPlayer().dimension));
	}

Packet/message registering (called in preinit, netWrapper is an instance of SimpleNetworkWrapper):

	public static void loadPackets() {
		int i = 0;
		for (Class clazz : new Reflections("com.ptsmods.morecommands.net").getSubTypesOf(AbstractPacket.class)) {
			try {
				Reference.print(LogType.INFO, "Registering packet", clazz.getName(), "of handler class", clazz.getDeclaredMethod("getHandler").invoke(null).getClass().getName(), "with a discriminator of", i++ + ".");
				netWrapper.registerMessage((IMessageHandler) clazz.getDeclaredMethod("getHandler").invoke(null), clazz, i, clazz.getName().startsWith("Server") ? Side.CLIENT : Side.SERVER);
			} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException
					| NoSuchMethodException | SecurityException e) {
				e.printStackTrace();
			}
		}
	}

ClientLeftClickEventPacket.java:

package com.ptsmods.morecommands.net;

import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

import com.google.gson.Gson;
import com.ptsmods.morecommands.miscellaneous.Reference;
import com.ptsmods.morecommands.miscellaneous.Reference.LogType;

import io.netty.buffer.ByteBuf;
import net.minecraft.server.MinecraftServer;
import net.minecraft.util.DamageSource;
import net.minecraft.util.EnumFacing;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.RayTraceResult;
import net.minecraft.util.math.Vec3d;
import net.minecraftforge.fml.common.FMLCommonHandler;
import net.minecraftforge.fml.common.network.simpleimpl.IMessage;
import net.minecraftforge.fml.common.network.simpleimpl.IMessageHandler;
import net.minecraftforge.fml.common.network.simpleimpl.MessageContext;

public class ClientLeftClickEventPacket extends AbstractPacket {

	private static final IMessageHandler handler = new ClientLeftClickEventHandler();
	private int jsonLength;
	private String jsonResult;
	private int dimension;
	
	public ClientLeftClickEventPacket() { }
	
	public ClientLeftClickEventPacket(RayTraceResult result, int dimension) {
		if (result != null) {
			Map<String, String> s = new HashMap();
			s.put("subHit", "" + result.subHit);
			s.put("hitInfo", result.hitInfo == null ? "" : result.hitInfo.toString());
			s.put("blockPos", result.getBlockPos() == null ? ";;" : result.getBlockPos().getX() + ";" + result.getBlockPos().getY() + ";" + result.getBlockPos().getZ());
			s.put("type", result.typeOfHit == null ? "" : result.typeOfHit.name());
			s.put("sideHit", result.sideHit == null ? "" : result.sideHit.name());
			s.put("hitVec", result.hitVec == null ? ";;" : result.hitVec.x + ";" + result.hitVec.y + ";" + result.hitVec.z);
			s.put("entity", result.entityHit == null ? "" : result.entityHit.getUniqueID().toString());
			this.dimension = dimension;
			Gson gson = new Gson();
			jsonResult = gson.toJson(s);
		}
	}

	@Override
	public void fromBytes(ByteBuf buf) {
		buf.writeInt(jsonLength);
		buf.writeCharSequence(jsonResult, StandardCharsets.UTF_8);
		buf.writeInt(dimension);
	}

	@Override
	public void toBytes(ByteBuf buf) {
		jsonLength = buf.readInt();
		jsonResult = buf.readCharSequence(jsonLength, StandardCharsets.UTF_8).toString();
		dimension = buf.readInt();
	}
	
	public static IMessageHandler<? extends AbstractPacket, ?> getHandler() {
		return handler;
	}

	public static class ClientLeftClickEventHandler implements IMessageHandler<ClientLeftClickEventPacket, IMessage> {

		@Override
		public IMessage onMessage(ClientLeftClickEventPacket message, MessageContext ctx) {
			Reference.print(LogType.INFO, "Received message ClientLeftClickEventPacket");
			Map<String, String> s = new Gson().fromJson(message.jsonResult, Map.class);
			MinecraftServer server = FMLCommonHandler.instance().getMinecraftServerInstance();
			Vec3d hitVec = new Vec3d(Double.parseDouble(s.get("hitVec").split(";")[0]), Double.parseDouble(s.get("hitVec").split(";")[1]), Double.parseDouble(s.get("hitVec").split(";")[2]));
			RayTraceResult result;
			if (s.get("entity").equals("")) {
				result = new RayTraceResult(RayTraceResult.Type.valueOf(s.get("type")), hitVec, EnumFacing.valueOf(s.get("sideHit")), new BlockPos(Double.parseDouble(s.get("blockPos").split(";")[0]), Double.parseDouble(s.get("blockPos").split(";")[1]), Double.parseDouble(s.get("blockPos").split(";")[2])));
				server.getWorld(message.dimension).destroyBlock(result.getBlockPos(), false);
			} else {
				result = new RayTraceResult(server.getEntityFromUuid(UUID.fromString(s.get("entity"))), hitVec);
				result.entityHit.attackEntityFrom(DamageSource.GENERIC, 4);
			}
			return null;
		}
	}

}

AbstractPacket.java:

package com.ptsmods.morecommands.net;

import io.netty.buffer.ByteBuf;
import net.minecraftforge.fml.common.network.simpleimpl.IMessage;
import net.minecraftforge.fml.common.network.simpleimpl.IMessageHandler;

public abstract class AbstractPacket implements IMessage {

	@Override
	public abstract void fromBytes(ByteBuf buf);

	@Override
	public abstract void toBytes(ByteBuf buf);
	
	public static IMessageHandler<? extends AbstractPacket, ?> getHandler() {
		return null;
	}

}

And when sending a different packet, ServerBlockReachUpdate, from the server, the same exception is thrown.

ServerBlockReachUpdate.java:

package com.ptsmods.morecommands.net;

import com.ptsmods.morecommands.miscellaneous.Reference;
import com.ptsmods.morecommands.miscellaneous.Reference.LogType;

import io.netty.buffer.ByteBuf;
import net.minecraftforge.fml.common.network.simpleimpl.IMessage;
import net.minecraftforge.fml.common.network.simpleimpl.IMessageHandler;
import net.minecraftforge.fml.common.network.simpleimpl.MessageContext;

public class ServerBlockReachUpdatePacket extends AbstractPacket {

	public int blockReach;
	private static final IMessageHandler handler = new ServerBlockReachUpdateHandler();
	
	public ServerBlockReachUpdatePacket(int blockReach) {
		this.blockReach = blockReach;
	}

	@Override
	public void fromBytes(ByteBuf buf) {
		Reference.print(LogType.INFO, buf.capacity());
		buf.writeInt(blockReach);
	}

	@Override
	public void toBytes(ByteBuf buf) {
		blockReach = buf.readInt();
	}
	
	public static IMessageHandler<? extends AbstractPacket, ?> getHandler() {
		return handler;
	}

	public static class ServerBlockReachUpdateHandler implements IMessageHandler<ServerBlockReachUpdatePacket, IMessage> {

		@Override
		public IMessage onMessage(ServerBlockReachUpdatePacket message, MessageContext ctx) {
			Reference.setBlockReach(message.blockReach);
			return null;
		}
	}
	
}

 

Edited April 14, 2019 by PlanetTeamSpeak

[V0idWa1k3r]

You are writing in the read function and reading in the write function.

 

Quote

@Override
    public void fromBytes(ByteBuf buf) {
        buf.writeInt(jsonLength);
        buf.writeCharSequence(jsonResult, StandardCharsets.UTF_8);
        buf.writeInt(dimension);
    }

    @Override
    public void toBytes(ByteBuf buf) {
        jsonLength = buf.readInt();
        jsonResult = buf.readCharSequence(jsonLength, StandardCharsets.UTF_8).toString();
        dimension = buf.readInt();
    }

 

[PlanetTeamSpeak]

1 minute ago, V0idWa1k3r said:

You are writing in the read function and reading in the write function.

 

 

Omg wow, thanks for pointing that out. I cannot believe how obvious it was, but I totally overlooked it. Thank you! I'll try it asap and return if I have any problems.