[SOLVED] [1.21] Packets Registering

[lusty patrol]

So, shortly, I have two packets:

1. Client To Server
2. Server To Client

I understand how packets looks like in 1.21, but their registering is very weird thing

For example I have this packets

public class TestS2CPacket implements CustomPayload {

    public static final Identifier PACKET_ID = IdentifierUtils.id("test_packet_s2c");
    
    public static final Id<TestS2CPacket> TYPE = new Id<>(PACKET_ID);
    public static final PacketCodec<RegistryByteBuf, TestS2CPacket> CODEC = CustomPayload.codecOf(TestS2CPacket::write, TestS2CPacket::new);

    private final String message;

    public TestS2CPacket(String message) {
        this.message = message;
    }

    public TestS2CPacket(RegistryByteBuf buf) {
        this.message = buf.readString();
    }
    
    public void write(RegistryByteBuf buf) {
        buf.writeString(this.message);
    }
    
    @Override
    public Id<? extends CustomPayload> getId() {
        return TYPE;
    }
}

public class TestC2SPacket implements CustomPayload {

    public static final Identifier PACKET_ID = IdentifierUtils.id("test_packet_c2s");
    
    public static final Id<TestC2SPacket> TYPE = new Id<>(PACKET_ID);
    public static final PacketCodec<RegistryByteBuf, TestC2SPacket> CODEC = CustomPayload.codecOf(TestC2SPacket::write, TestC2SPacket::new);

    private final String message;

    public TestC2SPacket(String message) {
        this.message = message;
    }

    public TestC2SPacket(RegistryByteBuf buf) {
        this.message = buf.readString();
    }
    
    public void write(RegistryByteBuf buf) {
        buf.writeString(this.message);
    }
    
    @Override
    public Id<? extends CustomPayload> getId() {
        return TYPE;
    }
}

Read messages below

And I have two manager classes for their registering at client and server side

public class ClientPacketManager {
    // This method invokes only at client initializing (ClientModInitializer)
    public static void register() {
        // Firstly, I need to register TestS2CPacket here, but I really don't know how to
        // do that right

        ClientPlayNetworking.registerGlobalReceiver(TestS2CPacket.TYPE, ((payload, context) -> {
            // handling here
        }));
    }
}

public class ServerPacketManager {
    // This method invokes only at common initializing (ModInitializer)
    public static void register() {
        // Firstly, I need to register TestC2SPacket here, but I really don't know how to
        // do that right

        ServerPlayNetworking.registerGlobalReceiver(TestC2SPacket.TYPE, ((payload, context) -> {
            // handling here
        }));
    }
}

My mod can be installed on the server, and that means that server will only invoke ServerPacketManager.register();, but the client will invoke and ServerPacketManager.register();, and ClientPacketManager.register();

[west musk]

What exactly is the issue?

[lusty patrol]

And I'm not sure that's right, because when I do that, client-side throws when trying to decode TestS2CPacket 🤔

[west musk]

That is right, you register packets for the logical sides, not the physical sides

Also kind of weird to have packets with buffers when you should be doing packet codecs on pojos

Have you read the 1.20.5 blog's networking changes?

https://fabricmc.net/2024/04/19/1205.html

[lusty patrol]

Yes, I read, but I still don’t understand how I should register packets and on which sides via PayloadTypeRegistry

[west musk]

You first register the payload on both sides

and only after that you register the handlers

[west musk]

(ie from the common mod initializer)

[lusty patrol]

Should I do something like that?

public class ServerPacketManager {
    // This method invokes only at common initializing (ModInitializer)
    public static void register() {
        // Firstly, I need to register TestS2CPacket here, but I really don't know how to
        // do that right
        PayloadTypeRegistry.playS2C().register(TestS2CPacket.TYPE, TestS2CPacket.CODEC);
        PayloadTypeRegistry.playC2S().register(TestC2SPacket.TYPE, TestC2SPacket.CODEC);

        ServerPlayNetworking.registerGlobalReceiver(TestC2SPacket.TYPE, ((payload, context) -> {
            // handling here
        }));
    }
}

[west musk]

What you did there was register TestS2CPacket and TestC2SPacket payloads (like two separate packet payloads and then registered the server side handler for TestC2SPacket

Yes that looks correct to me

[lusty patrol]

It means that registering TestS2CPacket at ClientPacketManager.register(); will be wrong?

[west musk]

Why would it be wrong?

You are registering the receiver on the side that's bound to receive the packet

If the packet is S2C, it means it's clientbound

Meaning the client is the one handling it coming in

[lusty patrol]

Hmm, then it's strange because I gets this error

Here is their registration and my packets

Sorry for so many stonecutter comments

[regal bluff]

let me repeat it: you must register the payload type on BOTH logical sides, regardless of where you receive it. Then, you register the listener only on the receiving logical side

[lusty patrol]

Okay, looks like I got it

Let me check

Yeah, now it works

[lusty patrol]

I did it like that

A lot of thanks @west musk ❤️ and @regal bluff ❤️

I think this post will be useful to others in the future