Is it possible for a clientside mod to read chunk NBT data, or is the data only accessible from the server? Is the chunk data on the client synced with the server chunk data? Does the client even know about the chunk data?

 

This goes for most other things, as well. How do I know what code the client has access to? Is it true that if there isn't a world.isRemote check, the client has full access to reading game logic code that you would expect to be on the server?

Since Minecraft's big bandwidth hog is the transfer of chunks from server to client, I am confident that chunk data exists on the client (at least within viewing range, once it has loaded). I think it was the presence of all that data that made xray cheat mods possible.

 

The server does update chunk data, though I suppose some are updated more frequently than others. One way to see an update is to measure the lag between when you mine a block on your client and when you see its drops appear -- there's a round-trip communication with the server in between. If you have ever lost a connection, you may have had the experience of mining blocks and blocks without any drops appearing.

 

Basically - what client sees, client has.

Note that some of TileEntities are not always synchronized to client (their data). Some other stuff too.

 

How do I know what code the client has access to? Is it true that if there isn't a world.isRemote check, the client has full access to reading game logic code that you would expect to be on the server?

 

http://www.minecraftforge.net/forum/index.php/topic,33918.msg178740.html#msg178740