[1.12.2] How to send Capability info through packets

[GooberGunter]

So I have a capability of an int array that assigns 5 values to each chunk. I also have an Item that is supposed to read the array in the chunk that the player is currently in. 

How do I use these packets? I already made them and I get the general idea of how they work, but I just don't know how to send them.

 

My major problem is that i need an EntityPlayerMP, which is the same player as the one who activated the item "playerIn" but I don't know how to pass that on from EntityPlayer to EntityPlayerMP, since casting is out of the question

Spoiler

@Override
	public ActionResult<ItemStack> onItemRightClick(World worldIn, EntityPlayer playerIn, EnumHand handIn)
    {
        //TODO sense the stuff
			Chunk chunk = worldIn.getChunkFromBlockCoords(playerIn.getPosition());
			IArcana a = chunk.getCapability(ArcanaProvider.ARCANA_CAP, null);
			int[] s = a.getArcana();
			//TODO find a way to convert single player to multiplayer
			GrandSorcery.handler.INSTANCE.sendTo(new ElementMessage(s), entityPlayerMP);
			
	
		if(worldIn.isRemote) {
			int f = element[0];
			int ai = element[1];
			int ea = element[2];
			int w = element[3];
			int ar = element[4];
			playerIn.sendMessage(new TextComponentTranslation("Fire: "+f+" Air: "+ai+" Earth: "+ea+" Water: "+w+" Arcana: "+ar));
			Util.logger.info("Fire: "+f+" Air: "+ai+" Earth: "+ea+" Water: "+w+" Arcana: "+ar);
		}
		return new ActionResult<ItemStack>(EnumActionResult.PASS, playerIn.getHeldItem(handIn));
    }
	
	public static void setElement(int[] val) {
		element = val;
	}

 

 

 

Edited December 14, 2017 by GooberGunter

[GooberGunter]

Is there some sort of way to link the EntityPlayer from the method to EntityPlayerMP?

Edited December 14, 2017 by GooberGunter
Accidentally thought I found a bigger problem but it was just because I was loading from an older save