Client code running on server side?

[mcmodder1]

I'm having some trouble with getting event handlers to run only on the client. My mod has a number of them that but here I'll just give code for one of them as an example.

 

For example, I would like to print a chat message when a certain entity spawns. To do this I am subscribing to a Forge event like so:

 

// register the event listener
MinecraftForge.EVENT_BUS.register(this);

 

@ForgeSubscribe
@SideOnly(Side.CLIENT) // <-- shouldn't this prevent Forge from calling this on the server side?
public void onEntitySpawn(EntityJoinWorldEvent event) {
	// check for specific entity, print chat message here
}

 

What I expect to happen is to see exactly one chat message printed when the entity spawns. However, what actually happens is I see two messages printed. From examining the callstack, I can see that one call comes from net.minecraft.server.* and the other call comes from net.minecraft.client.*. (This is on a singleplayer world. If I join a server then code works fine and the message prints just once.)

 

So, my first question is: Does @SideOnly(Side.CLIENT) not work here? Shouldn't it make my method only be called on the client side?

 

I did some more research and read that I might need to use a "Proxy" to separate client/server behavior. I changed my code to the below:

 

@SidedProxy(clientSide = "com.example.MyMod$ClientEventProxy", serverSide = "com.example.MyMod$BaseEventProxy")
public static BaseEventProxy proxy;

public static class BaseEventProxy {
	public void registerForEvents() {}
}

public static class ClientEventProxy extends BaseEventProxy {
	public void registerForEvents() {
		MinecraftForge.EVENT_BUS.register(this);
	}

	@ForgeSubscribe
	@SideOnly(Side.CLIENT) // This probably does nothing, but I left it here anyways
	public void onEntitySpawn(EntityJoinWorldEvent event) {
		// check for specific entity, print chat message here
	}
}

 

However, this doesn't make any difference. I still see the message being printed twice. (And, having read this, that makes sense. Basically, it says that the client/server proxy is for mods that can run on both the dedicated server and the client with integrated server.)

 

So, my second question is: Given that @SidedProxy doesn't do what I require, how can I make Forge only call my event listener once, on the client side only? (I did do some more research into this and it looks like I can check either FMLCommonHandler.instance().getEffectiveSide() or World.isRemote but is that the best practice?)

[mcmodder1]

Okay, that makes sense now. I'll use world.isRemote. Thanks!