Update protocol to only send block headers

[alexdovzhanyn]

We're currently sending the entirety of all block data when relaying a block. This can be cut down by sending only block headers and allowing peers to download the block body from us if they need it.

[leeaaron629]

Hi,

I would like to work on this issue! What would be the acceptance criteria? And how would I go about proving it?

[alexdovzhanyn]

@onlyhope Hey! Thanks for your interest in this issue -- excited to have you contribute. This should be relatively a straightforward change -- we have a Block.header/1 method that returns just the header of the block that can be used for this, it should be as simple as changing the router file to use the function and updating the message type broadcasted.

I'll work in tandem with you once you submit the PR because we'll need to change the logic for block downloading on the receiving end.

Let me know if you have any questions or run into any issues!

[leeaaron629]

Hi @alexdovzhanyn ,

I've taken a look at the code and let me make sure I understand it before I start implementation.

So I've see an Elixium.Store.Ledger module. You want me to change the Ledger.retrieve_chain/1 method to return a block headers instead? And if the user requires more detail they can call the Ledger.retrieve_block/1?