I'm trying to modify the block structure for a blockchain based on Substrate that I'm trying to develop. In particular I would like to add a vector in the header and another one inside the body of the block. Does someone know how it is possible to do that?
I'm a newbie in Substrate :'(
Thanks in advance to everyone who will contribute!
The block and header type in Substrate are generic.
The header needs to implement https://docs.rs/sp-runtime/latest/sp_runtime/traits/trait.Header.html and the block needs to implement https://docs.rs/sp-runtime/latest/sp_runtime/traits/trait.Block.html.
Substrate itself provides two types for that already https://docs.rs/sp-runtime/latest/sp_runtime/generic/struct.Block.html and https://docs.rs/sp-runtime/latest/sp_runtime/generic/struct.Header.html.
When you setup your blockchain, which you mainly do through the runtime you can choose these types.
If you're after including some data for each block then it's called an Inherent extrinsic ( https://docs.substrate.io/v3/concepts/extrinsics/#inherents ) and would not have a fee associated with it.
Header is a type defined in your runtime so you can change it to include any additional data that you'd like. Search for this definition:
pub type Header = generic::Header<BlockNumber, BlakeTwo256>;
See it in context here: https://github.com/substrate-developer-hub/substrate-node-template/blob/ad7ce8e3dabb2d1f8f4b4094db5b0e754760e9be/runtime/src/lib.rs#L75