Client-side JS to SCALE conversion

[jmg-duarte]

The signature for signed deals is built on top of the SCALE encoded deal proposal (more or less like so):

fn sign(deal_proposal: DealProposal) -> SignedDealProposal {
  return sign(deal_proposal.to_scale())

Currently, we send the proposal to the SP to encode, which is far from ideal:

delia/src/components/storage-deal/StorageDealFlow.jsx

Lines 213 to 217 in cded5af

	const encodingResponse = await fetch(`http://${providerUrl}:${HTTP_PORT}/encode_proposal`, {
	method: 'POST',
	headers: { 'Content-Type': 'application/json' },
	body: JSON.stringify(dealProposal),
	});

The SCALE library is no_std compatible and so is serde, so we can probably get a WASM function for the encoding working.

Maybe we won't need the WASM — https://github.com/polkadot-js/api/tree/f96e8c42a06b934d7e512c6427b81a995faa417a/packages/types-codec

[jmg-duarte]

I did some additional research and we should be able to copy the Rust structs to TS using the types-codec and it's friends.

https://grep.app/search?q=%40polkadot/types-codec

The following guide should be helpful:

• https://polkadot.js.org/docs/api/start/types.create

Seems to me that the approach revolves around using the type registry to create the types:

import { TypeRegistry } from '@polkadot/types';

const registry = new TypeRegistry();
registry.register(...);
registry.createType("DealProposal", ...);

However, I don't understand Typescript enough to understand the source of CodecClass

[jmg-duarte]

This has been implemented and is working but hasn't reached the main tree yet

• https://github.com/eigerco/delia/blob/7d2aa9857c8d68b4696994e9a37fc2c336040163/src/lib/registry.ts

• delia/src/lib/dealProposal.ts

  Lines 169 to 175 in 7d2aa98

  	async toSignedRpc(provider: string, registry: TypeRegistry, account: InjectedAccountWithMeta): Promise<SignedRpc> {
  	const rpc = this.toRpc(provider)
  	const scale = this.toSCALEable(provider).encode(registry)
  	const signed = await signRaw(account, u8aToHex(scale));
  	return new SignedRpc(signed, rpc)
  	}

• https://github.com/eigerco/delia/blob/7d2aa9857c8d68b4696994e9a37fc2c336040163/src/lib/sign.ts