Patch the new cbook exploit

Plugin category: Essential

Minecraft version: Effects all Minecraft versions, but I'm on 1.8.8

Suggested name: cbook patch (creative ik)

What I want: A fix for the growing exploit cbook where players can duplicate items using chinese chars in a book n quill. Here's a video linking the exploit.

Ideas for commands: No commands needed for this plugin.

Ideas for permissions: player.cancbook

When I'd like it by: Before that player gave me a pleasant surprise of filling my inventory with crate keys

 

I made it so that books must only contain alphanumeric characters, you can test this after you put in non-alphanumeric characters and click 'Done' or 'Sign' and it will cancel the book being made.
You can download this HERE

 

You are a true G, thank you so much

 

Mark this as filled if it is complete.