IndexArrayOutOfBoundsException on packet send

[Insane96MCP]

As I try to send a test packet (PacketHandler.SendToServer(new TestMessage(10))) to server I get this huge exception:

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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) ~[MessageToMessageEncoder.class:4.1.9.Final]
	at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116) ~[MessageToMessageCodec.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:801) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:814) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:794) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:831) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1032) ~[DefaultChannelPipeline.class:4.1.9.Final]
	at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:296) ~[AbstractChannel.class:4.1.9.Final]
	at net.minecraftforge.fml.common.network.simpleimpl.SimpleNetworkWrapper.sendToServer(SimpleNetworkWrapper.java:289) [SimpleNetworkWrapper.class:?]
	at net.insane96mcp.iguanatweaks.network.PacketHandler.SendToServer(PacketHandler.java:19) [PacketHandler.class:?]
	at net.insane96mcp.iguanatweaks.modules.ModuleDrops.PlayerToss(ModuleDrops.java:76) [ModuleDrops.class:?]
	at net.insane96mcp.iguanatweaks.events.ItemToss.EventItemToss(ItemToss.java:11) [ItemToss.class:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_33_ItemToss_EventItemToss_ItemTossEvent.invoke(.dynamic) [?:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) [ASMEventHandler.class:?]
	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:179) [EventBus.class:?]
	at net.minecraftforge.common.ForgeHooks.onPlayerTossEvent(ForgeHooks.java:681) [ForgeHooks.class:?]
	at net.minecraft.entity.player.EntityPlayer.dropItem(EntityPlayer.java:780) [EntityPlayer.class:?]
	at net.minecraft.network.NetHandlerPlayServer.processPlayerDigging(NetHandlerPlayServer.java:679) [NetHandlerPlayServer.class:?]
	at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:56) [CPacketPlayerDigging.class:?]
	at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:12) [CPacketPlayerDigging.class:?]
	at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:21) [PacketThreadUtil$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_161]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_161]
	at net.minecraft.util.Util.runTask(Util.java:53) [Util.class:?]
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:796) [MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:741) [MinecraftServer.class:?]
	at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:192) [IntegratedServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:590) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_161]
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) ~[AbstractByteBuf.class:4.1.9.Final]
	at io.netty.buffer.AbstractByteBuf.readInt(AbstractByteBuf.java:766) ~[AbstractByteBuf.class:4.1.9.Final]
	at net.minecraft.network.PacketBuffer.readInt(PacketBuffer.java:953) ~[PacketBuffer.class:?]
	at net.insane96mcp.iguanatweaks.network.TestMessage.toBytes(TestMessage.java:20) ~[TestMessage.class:?]
	at net.minecraftforge.fml.common.network.simpleimpl.SimpleIndexedCodec.encodeInto(SimpleIndexedCodec.java:30) ~[SimpleIndexedCodec.class:?]
	at net.minecraftforge.fml.common.network.simpleimpl.SimpleIndexedCodec.encodeInto(SimpleIndexedCodec.java:26) ~[SimpleIndexedCodec.class:?]
	at net.minecraftforge.fml.common.network.FMLIndexedMessageToMessageCodec.encode(FMLIndexedMessageToMessageCodec.java:71) ~[FMLIndexedMessageToMessageCodec.class:?]
	at io.netty.handler.codec.MessageToMessageCodec$1.encode(MessageToMessageCodec.java:67) ~[MessageToMessageCodec$1.class:4.1.9.Final]
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88) ~[MessageToMessageEncoder.class:4.1.9.Final]
	... 29 more
Mar 26, 2018 12:03:38 PM io.netty.channel.embedded.EmbeddedChannel recordException
WARNING: More than one exception was raised. Will report only the first one and log others.
io.netty.handler.codec.EncoderException: java.lang.IndexOutOfBoundsException: readerIndex(0) + length(4) exceeds writerIndex(1): UnpooledByteBufAllocator$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:289)
	at net.insane96mcp.iguanatweaks.network.PacketHandler.SendToServer(PacketHandler.java:19)
	at net.insane96mcp.iguanatweaks.modules.ModuleDrops.PlayerToss(ModuleDrops.java:76)
	at net.insane96mcp.iguanatweaks.events.ItemToss.EventItemToss(ItemToss.java:11)
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_33_ItemToss_EventItemToss_ItemTossEvent.invoke(.dynamic)
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90)
	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:179)
	at net.minecraftforge.common.ForgeHooks.onPlayerTossEvent(ForgeHooks.java:681)
	at net.minecraft.entity.player.EntityPlayer.dropItem(EntityPlayer.java:780)
	at net.minecraft.network.NetHandlerPlayServer.processPlayerDigging(NetHandlerPlayServer.java:679)
	at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:56)
	at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:12)
	at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:21)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at net.minecraft.util.Util.runTask(Util.java:53)
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:796)
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:741)
	at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:192)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:590)
	at java.lang.Thread.run(Thread.java:748)
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 net.insane96mcp.iguanatweaks.network.TestMessage.toBytes(TestMessage.java:20)
	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:71)
	at io.netty.handler.codec.MessageToMessageCodec$1.encode(MessageToMessageCodec.java:67)
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88)
	... 29 more

 

 

PacketHandler

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package net.insane96mcp.iguanatweaks.network;

import net.insane96mcp.iguanatweaks.IguanaTweaks;
import net.minecraftforge.fml.common.network.NetworkRegistry;
import net.minecraftforge.fml.common.network.simpleimpl.SimpleNetworkWrapper;
import net.minecraftforge.fml.relauncher.Side;

public class PacketHandler {
	public static final SimpleNetworkWrapper INSTANCE = NetworkRegistry.INSTANCE.newSimpleChannel(IguanaTweaks.MOD_ID);
	private static int discriminator = 0;
	
	public static void Init() {
		INSTANCE.registerMessage(TestMessageHandler.class, TestMessage.class, discriminator++, Side.SERVER);
	}
	
	public static void SendToServer(TestMessage message) {
		INSTANCE.sendToServer(message);
	}
}

 

 

IMessage implementation

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package net.insane96mcp.iguanatweaks.network;

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

public class TestMessage implements IMessage {

	public int toSend;
	public TestMessage(int toSend) {
		this.toSend = toSend;
	}
	
	@Override
	public void fromBytes(ByteBuf buf) {
		buf.writeInt(toSend);
	}

	@Override
	public void toBytes(ByteBuf buf) {
		this.toSend = buf.readInt();
	}

}

 

 

IMessageHandler implementation

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package net.insane96mcp.iguanatweaks.network;

import net.minecraft.entity.player.EntityPlayerMP;
import net.minecraft.init.Items;
import net.minecraft.item.ItemStack;
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 TestMessageHandler implements IMessageHandler<TestMessage, IMessage> {

	@Override
	public IMessage onMessage(TestMessage message, MessageContext ctx) {
		EntityPlayerMP serverPlayer = ctx.getServerHandler().player;
		int amount = message.toSend;
		serverPlayer.getServerWorld().addScheduledTask(() -> {
			serverPlayer.inventory.addItemStackToInventory(new ItemStack(Items.DIAMOND, amount));
	    });
		return null;
	}

}

 

 

The Packet handler has been registered in the PreInit of the CommonProxy with PacketHandler.Init()
I really don't know what I'm doing wrong since I've followed the docs of SimpleImpl

Edited March 26, 2018 by Insane96MCP

[Choonster]

You've got your fromBytes and toBytes implementations around the wrong way. fromBytes needs to read the data from the byte buffer into the fields of the packet; toBytes needs to write the data from the fields of the packet into the byte buffer.

[Insane96MCP]

How do I handle messages from server to client?

I can use ctx.getServerHandler().player to get the PlayerMP, but how do I get the client one?