Begin work on the new RPC for the new node

substrate/node/src/rpc/blockchain.rs

@@ -0,0 +1,52 @@
+use std::{sync::Arc, ops::Deref, collections::HashSet};
+
+use rand_core::{RngCore, OsRng};
+
+use sp_core::Encode;
+use sp_blockchain::{Error as BlockchainError, HeaderMetadata, HeaderBackend};
+use sp_block_builder::BlockBuilder;
+use sp_api::ProvideRuntimeApi;
+
+use serai_abi::{primitives::prelude::*, SubstrateBlock as Block};
+use serai_runtime::*;
+
+use jsonrpsee::RpcModule;
+
+use sc_client_api::BlockBackend;
+
+pub(crate) fn module<
+  C: 'static
+    + Send
+    + Sync
+    + HeaderMetadata<Block, Error = BlockchainError>
+    + HeaderBackend<Block>
+    + BlockBackend<Block>
+    + ProvideRuntimeApi<Block>,
+>(
+  client: Arc<C>,
+) -> Result<RpcModule<impl 'static + Send + Sync>, Box<dyn std::error::Error + Send + Sync>> {
+  let mut module = RpcModule::new(client);
+  module.register_async_method("serai_block", |params, client, _ext| async move {
+    let [block_hash]: [String; 1] = params.parse()?;
+    let Some(block_hash) = hex::decode(&block_hash).ok().and_then(|bytes| {
+      <[u8; 32]>::try_from(bytes.as_slice())
+        .map(<Block as sp_runtime::traits::Block>::Hash::from)
+        .ok()
+    }) else {
+      return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
+        -1,
+        "requested block hash wasn't a valid hash",
+        Option::<()>::None,
+      ));
+    };
+    let Some(block) = client.block(block_hash).ok().flatten() else {
+      return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
+        -2,
+        "couldn't find requested block",
+        Option::<()>::None,
+      ));
+    };
+    Ok(hex::encode(block.block.encode()))
+  })?;
+  Ok(module)
+}

substrate/node/src/rpc/mod.rs

@@ -0,0 +1,149 @@
+use std::{sync::Arc, ops::Deref, collections::HashSet};
+
+use rand_core::{RngCore, OsRng};
+
+use sp_core::Encode;
+use sp_blockchain::{Error as BlockchainError, HeaderBackend, HeaderMetadata};
+use sp_block_builder::BlockBuilder;
+use sp_api::ProvideRuntimeApi;
+
+use serai_abi::{primitives::prelude::*, SubstrateBlock as Block};
+use serai_runtime::*;
+
+use tokio::sync::RwLock;
+
+use jsonrpsee::RpcModule;
+
+use sc_client_api::BlockBackend;
+use sc_transaction_pool_api::TransactionPool;
+
+mod blockchain;
+mod p2p_validators;
+
+pub struct FullDeps<C, P> {
+  pub id: String,
+  pub client: Arc<C>,
+  pub pool: Arc<P>,
+  pub authority_discovery: Option<sc_authority_discovery::Service>,
+}
+
+pub fn create_full<
+  C: 'static
+    + Send
+    + Sync
+    + ProvideRuntimeApi<Block, Api: BlockBuilder<Block> + serai_runtime::SeraiApi<Block>>
+    + HeaderBackend<Block>
+    + HeaderMetadata<Block, Error = BlockchainError>
+    + BlockBackend<Block>,
+  P: 'static + TransactionPool,
+>(
+  deps: FullDeps<C, P>,
+) -> Result<RpcModule<()>, Box<dyn std::error::Error + Send + Sync>> {
+  let FullDeps { id, client, pool, authority_discovery } = deps;
+
+  let mut root = RpcModule::new(());
+  root.merge(blockchain::module(client.clone())?)?;
+  if let Some(authority_discovery) = authority_discovery {
+    root.merge(p2p_validators::module(id, client, authority_discovery)?)?;
+  }
+  Ok(root)
+
+  /* TODO
+  use ciphersuite::{GroupIo, WithPreferredHash};
+  use ciphersuite_kp256::{k256::elliptic_curve::point::AffineCoordinates, Secp256k1};
+  use dalek_ff_group::Ed25519;
+  use bitcoin_serai::bitcoin;
+
+  let mut serai_json_module = RpcModule::new(client);
+
+  // add network address rpc
+  serai_json_module.register_async_method(
+    "external_network_address",
+    |params, context| async move {
+      let network: ExternalNetworkId = params.parse()?;
+      let client = &*context;
+      let latest_block = client.info().best_hash;
+
+      let external_key = client
+        .runtime_api()
+        .external_network_key(latest_block, network)
+        .map_err(|_| Error::Custom("api call error".to_string()))?
+        .ok_or(Error::Custom("no address for the network".to_string()))?;
+
+      match network {
+        ExternalNetworkId::Bitcoin => {
+          let key = <Secp256k1 as GroupIo>::read_G::<&[u8]>(&mut external_key.as_slice())
+            .map_err(|_| Error::Custom("invalid key stored in db".to_string()))?;
+
+          let addr = bitcoin::Address::p2tr_tweaked(
+            bitcoin::key::TweakedPublicKey::dangerous_assume_tweaked(
+              bitcoin::key::XOnlyPublicKey::from_slice(key.to_affine().x().as_slice()).map_err(
+                |_| Error::Custom("x-coordinate for Bitcoin key was invalid".to_string()),
+              )?,
+            ),
+            bitcoin::address::KnownHrp::Mainnet,
+          );
+
+          Ok(addr.to_string())
+        }
+        // We don't know the eth address before the smart contract is deployed.
+        ExternalNetworkId::Ethereum => Ok(String::new()),
+        ExternalNetworkId::Monero => {
+          // TODO: Serai view-key crate
+          let view_private = zeroize::Zeroizing::new(<Ed25519 as WithPreferredHash>::hash_to_F(
+            &["Monero".as_bytes(), &0u64.to_le_bytes()].concat(),
+          ));
+
+          let spend = <Ed25519 as GroupIo>::read_G::<&[u8]>(&mut external_key.as_slice())
+            .map_err(|_| Error::Custom("invalid key stored in db".to_string()))?;
+
+          let addr = monero_address::MoneroAddress::new(
+            monero_address::Network::Mainnet,
+            monero_address::AddressType::Featured {
+              subaddress: false,
+              payment_id: None,
+              guaranteed: true,
+            },
+            *spend,
+            view_private.deref() * curve25519_dalek::constants::ED25519_BASEPOINT_TABLE,
+          );
+
+          Ok(addr.to_string())
+        }
+      }
+    },
+  )?;
+
+  // add shorthand encoding rpc
+  serai_json_module.register_async_method("encoded_shorthand", |params, _| async move {
+    // decode using serde and encode back using scale
+    let shorthand: Shorthand = params.parse()?;
+    Ok(shorthand.encode())
+  })?;
+
+  // add simulating a swap path rpc
+  serai_json_module.register_async_method("quote_price", |params, context| async move {
+    let client = &*context;
+    let latest_block = client.info().best_hash;
+    let QuotePriceParams { coin1, coin2, amount, include_fee, exact_in } = params.parse()?;
+
+    let amount = if exact_in {
+      client
+        .runtime_api()
+        .quote_price_exact_tokens_for_tokens(latest_block, coin1, coin2, amount, include_fee)
+        .map_err(|_| Error::Custom("api call error".to_string()))?
+        .ok_or(Error::Custom("invalid params or empty pool".to_string()))?
+    } else {
+      client
+        .runtime_api()
+        .quote_price_tokens_for_exact_tokens(latest_block, coin1, coin2, amount, include_fee)
+        .map_err(|_| Error::Custom("api call error".to_string()))?
+        .ok_or(Error::Custom("invalid params or empty pool".to_string()))?
+    };
+
+    Ok(amount)
+  })?;
+
+  module.merge(serai_json_module)?;
+  */
+}

substrate/node/src/rpc/p2p_validators.rs

@@ -0,0 +1,86 @@
+use std::{sync::Arc, ops::Deref, collections::HashSet};
+
+use rand_core::{RngCore, OsRng};
+
+use sp_core::Encode;
+use sp_blockchain::{Error as BlockchainError, HeaderBackend};
+use sp_api::ProvideRuntimeApi;
+
+use serai_abi::{primitives::prelude::*, SubstrateBlock as Block};
+use serai_runtime::*;
+
+use tokio::sync::RwLock;
+
+use jsonrpsee::RpcModule;
+
+pub(crate) fn module<
+  C: 'static
+    + Send
+    + Sync
+    + HeaderBackend<Block>
+    + ProvideRuntimeApi<Block, Api: serai_runtime::SeraiApi<Block>>,
+>(
+  id: String,
+  client: Arc<C>,
+  authority_discovery: sc_authority_discovery::Service,
+) -> Result<RpcModule<impl 'static + Send + Sync>, Box<dyn std::error::Error + Send + Sync>> {
+  let mut module = RpcModule::new((id, client, RwLock::new(authority_discovery)));
+  module.register_async_method("p2p_validators", |params, context, _ext| async move {
+    let [network]: [String; 1] = params.parse()?;
+    let network = match network.to_lowercase().as_str() {
+      "serai" => NetworkId::Serai,
+      "bitcoin" => ExternalNetworkId::Bitcoin.into(),
+      "ethereum" => ExternalNetworkId::Ethereum.into(),
+      "monero" => ExternalNetworkId::Monero.into(),
+      _ => Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
+        -1,
+        "network to fetch the `p2p_validators` of was unrecognized".to_string(),
+        Option::<()>::None,
+      ))?,
+    };
+    let (id, client, authority_discovery) = &*context;
+    let latest_block = client.info().best_hash;
+
+    let validators = client.runtime_api().validators(latest_block, network).map_err(|_| {
+      jsonrpsee::types::error::ErrorObjectOwned::owned(
+        -2,
+        format!(
+          "couldn't get validators from the latest block, which is likely a fatal bug. {}",
+          "please report this at https://github.com/serai-dex/serai",
+        ),
+        Option::<()>::None,
+      )
+    });
+    let validators = match validators {
+      Ok(validators) => validators,
+      Err(e) => return Err(e),
+    };
+    // Always return the protocol's bootnodes
+    let mut all_p2p_addresses = crate::chain_spec::bootnode_multiaddrs(id);
+    // Additionally returns validators found over the DHT
+    for validator in validators {
+      let mut returned_addresses = authority_discovery
+        .write()
+        .await
+        .get_addresses_by_authority_id(validator.into())
+        .await
+        .unwrap_or_else(HashSet::new)
+        .into_iter()
+        .collect::<Vec<_>>();
+      // Randomly select an address
+      // There should be one, there may be two if their IP address changed, and more should only
+      // occur if they have multiple proxies/an IP address changing frequently/some issue
+      // preventing consistent self-identification
+      // It isn't beneficial to use multiple addresses for a single peer here
+      if !returned_addresses.is_empty() {
+        all_p2p_addresses.push(
+          returned_addresses
+            .remove(usize::try_from(OsRng.next_u64() >> 32).unwrap() % returned_addresses.len())
+            .into(),
+        );
+      }
+    }
+    Ok(all_p2p_addresses)
+  })?;
+  Ok(module)
+}