Support arbitrary RPC providers in monero-serai

Sets a clean path for no-std premised RPCs (buffers to an external RPC impl)/
Tor-based RPCs/client-side load balancing/...

Cargo.lock

@@ -5270,6 +5270,7 @@ dependencies = [
 name = "monero-serai"
 version = "0.1.4-alpha"
 dependencies = [
+ "async-trait",
  "base58-monero",
  "crc",
  "curve25519-dalek 3.2.0",

coins/monero/Cargo.toml

@@ -15,6 +15,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 futures = "0.3"
 
 lazy_static = "1"
+async-trait = "0.1"
 thiserror = "1"
 
 rand_core = "0.6"

coins/monero/src/rpc.rs

@@ -1,5 +1,6 @@
 use std::fmt::Debug;
 
+use async_trait::async_trait;
 use thiserror::Error;
 
 use curve25519_dalek::edwards::{EdwardsPoint, CompressedEdwardsY};
@@ -8,7 +9,7 @@ use serde::{Serialize, Deserialize, de::DeserializeOwned};
 use serde_json::{Value, json};
 
 use digest_auth::AuthContext;
-use reqwest::{Client, RequestBuilder};
+use reqwest::Client;
 
 use crate::{
   Protocol,
@@ -73,18 +74,27 @@ fn rpc_point(point: &str) -> Result<EdwardsPoint, RpcError> {
   .ok_or_else(|| RpcError::InvalidPoint(point.to_string()))
 }
 
+#[async_trait]
+pub trait RpcConnection: Clone + Debug {
+  /// Perform a POST request to the specified route with the specified body.
+  ///
+  /// The implementor is left to handle anything such as authentication.
+  async fn post(&self, route: &str, body: Vec<u8>) -> Result<Vec<u8>, RpcError>;
+}
+
 #[derive(Clone, Debug)]
-pub struct Rpc {
+pub struct HttpRpc {
   client: Client,
   userpass: Option<(String, String)>,
   url: String,
 }
 
-impl Rpc {
-  /// Create a new RPC connection.
+impl HttpRpc {
+  /// Create a new HTTP(S) RPC connection.
+  ///
   /// A daemon requiring authentication can be used via including the username and password in the
   /// URL.
-  pub fn new(mut url: String) -> Result<Rpc, RpcError> {
+  pub fn new(mut url: String) -> Result<Rpc<HttpRpc>, RpcError> {
     // Parse out the username and password
     let userpass = if url.contains('@') {
       let url_clone = url;
@@ -114,26 +124,80 @@ impl Rpc {
       None
     };
 
-    Ok(Rpc { client: Client::new(), userpass, url })
+    Ok(Rpc(HttpRpc { client: Client::new(), userpass, url }))
   }
+}
 
-  /// Perform a RPC call to the specified method with the provided parameters.
-  /// This is NOT a JSON-RPC call, which use a method of "json_rpc" and are available via
+#[async_trait]
+impl RpcConnection for HttpRpc {
+  async fn post(&self, route: &str, body: Vec<u8>) -> Result<Vec<u8>, RpcError> {
+    let mut builder = self.client.post(self.url.clone() + "/" + route).body(body);
+
+    if let Some((user, pass)) = &self.userpass {
+      let req = self.client.post(&self.url).send().await.map_err(|_| RpcError::InvalidNode)?;
+      // Only provide authentication if this daemon actually expects it
+      if let Some(header) = req.headers().get("www-authenticate") {
+        builder = builder.header(
+          "Authorization",
+          digest_auth::parse(header.to_str().map_err(|_| RpcError::InvalidNode)?)
+            .map_err(|_| RpcError::InvalidNode)?
+            .respond(&AuthContext::new_post::<_, _, _, &[u8]>(
+              user,
+              pass,
+              "/".to_string() + route,
+              None,
+            ))
+            .map_err(|_| RpcError::InvalidNode)?
+            .to_header_string(),
+        );
+      }
+    }
+
+    Ok(
+      builder
+        .send()
+        .await
+        .map_err(|_| RpcError::ConnectionError)?
+        .bytes()
+        .await
+        .map_err(|_| RpcError::ConnectionError)?
+        .slice(..)
+        .to_vec(),
+    )
+  }
+}
+
+#[derive(Clone, Debug)]
+pub struct Rpc<R: RpcConnection>(R);
+impl<R: RpcConnection> Rpc<R> {
+  /// Perform a RPC call to the specified route with the provided parameters.
+  ///
+  /// This is NOT a JSON-RPC call. They use a route of "json_rpc" and are available via
   /// `json_rpc_call`.
   pub async fn rpc_call<Params: Serialize + Debug, Response: DeserializeOwned + Debug>(
     &self,
-    method: &str,
+    route: &str,
     params: Option<Params>,
   ) -> Result<Response, RpcError> {
-    let mut builder = self.client.post(self.url.clone() + "/" + method);
-    if let Some(params) = params.as_ref() {
-      builder = builder.json(params);
-    }
-
-    self.call_tail(method, builder).await
+    self
+      .call_tail(
+        route,
+        self
+          .0
+          .post(
+            route,
+            if let Some(params) = params {
+              serde_json::to_string(&params).unwrap().into_bytes()
+            } else {
+              vec![]
+            },
+          )
+          .await?,
+      )
+      .await
   }
 
-  /// Perform a JSON-RPC call to the specified method with the provided parameters
+  /// Perform a JSON-RPC call with the specified method with the provided parameters
   pub async fn json_rpc_call<Response: DeserializeOwned + Debug>(
     &self,
     method: &str,
@@ -146,48 +210,25 @@ impl Rpc {
     Ok(self.rpc_call::<_, JsonRpcResponse<Response>>("json_rpc", Some(req)).await?.result)
   }
 
-  /// Perform a binary call to the specified method with the provided parameters.
+  /// Perform a binary call to the specified route with the provided parameters.
   pub async fn bin_call<Response: DeserializeOwned + Debug>(
     &self,
-    method: &str,
+    route: &str,
     params: Vec<u8>,
   ) -> Result<Response, RpcError> {
-    let builder = self.client.post(self.url.clone() + "/" + method).body(params.clone());
-    self.call_tail(method, builder.header("Content-Type", "application/octet-stream")).await
+    self.call_tail(route, self.0.post(route, params).await?).await
   }
 
   async fn call_tail<Response: DeserializeOwned + Debug>(
     &self,
-    method: &str,
-    mut builder: RequestBuilder,
+    route: &str,
+    res: Vec<u8>,
   ) -> Result<Response, RpcError> {
-    if let Some((user, pass)) = &self.userpass {
-      let req = self.client.post(&self.url).send().await.map_err(|_| RpcError::InvalidNode)?;
-      // Only provide authentication if this daemon actually expects it
-      if let Some(header) = req.headers().get("www-authenticate") {
-        builder = builder.header(
-          "Authorization",
-          digest_auth::parse(header.to_str().map_err(|_| RpcError::InvalidNode)?)
-            .map_err(|_| RpcError::InvalidNode)?
-            .respond(&AuthContext::new_post::<_, _, _, &[u8]>(
-              user,
-              pass,
-              "/".to_string() + method,
-              None,
-            ))
-            .map_err(|_| RpcError::InvalidNode)?
-            .to_header_string(),
-        );
-      }
-    }
-
-    let res = builder.send().await.map_err(|_| RpcError::ConnectionError)?;
-
-    Ok(if !method.ends_with(".bin") {
-      serde_json::from_str(&res.text().await.map_err(|_| RpcError::ConnectionError)?)
+    Ok(if !route.ends_with(".bin") {
+      serde_json::from_str(std::str::from_utf8(&res).map_err(|_| RpcError::InvalidNode)?)
         .map_err(|_| RpcError::InternalError("Failed to parse JSON response"))?
     } else {
-      monero_epee_bin_serde::from_bytes(&res.bytes().await.map_err(|_| RpcError::ConnectionError)?)
+      monero_epee_bin_serde::from_bytes(&res)
         .map_err(|_| RpcError::InternalError("Failed to parse binary response"))?
     })
   }

coins/monero/src/wallet/decoys.rs

@@ -13,7 +13,7 @@ use curve25519_dalek::edwards::EdwardsPoint;
 
 use crate::{
   wallet::SpendableOutput,
-  rpc::{RpcError, Rpc},
+  rpc::{RpcError, RpcConnection, Rpc},
 };
 
 const LOCK_WINDOW: usize = 10;
@@ -31,9 +31,9 @@ lazy_static! {
 }
 
 #[allow(clippy::too_many_arguments)]
-async fn select_n<'a, R: RngCore + CryptoRng>(
+async fn select_n<'a, R: RngCore + CryptoRng, RPC: RpcConnection>(
   rng: &mut R,
-  rpc: &Rpc,
+  rpc: &Rpc<RPC>,
   distribution: &MutexGuard<'a, Vec<u64>>,
   height: usize,
   high: u64,
@@ -137,9 +137,9 @@ impl Decoys {
   }
 
   /// Select decoys using the same distribution as Monero.
-  pub async fn select<R: RngCore + CryptoRng>(
+  pub async fn select<R: RngCore + CryptoRng, RPC: RpcConnection>(
     rng: &mut R,
-    rpc: &Rpc,
+    rpc: &Rpc<RPC>,
     ring_len: usize,
     height: usize,
     inputs: &[SpendableOutput],

coins/monero/src/wallet/scan.rs

@@ -10,7 +10,7 @@ use crate::{
   serialize::{read_byte, read_u32, read_u64, read_bytes, read_scalar, read_point, read_raw_vec},
   transaction::{Input, Timelock, Transaction},
   block::Block,
-  rpc::{Rpc, RpcError},
+  rpc::{RpcError, RpcConnection, Rpc},
   wallet::{
     PaymentId, Extra, address::SubaddressIndex, Scanner, uniqueness, shared_key, amount_decryption,
     commitment_mask,
@@ -195,13 +195,19 @@ pub struct SpendableOutput {
 impl SpendableOutput {
   /// Update the spendable output's global index. This is intended to be called if a
   /// re-organization occurred.
-  pub async fn refresh_global_index(&mut self, rpc: &Rpc) -> Result<(), RpcError> {
+  pub async fn refresh_global_index<RPC: RpcConnection>(
+    &mut self,
+    rpc: &Rpc<RPC>,
+  ) -> Result<(), RpcError> {
     self.global_index =
       rpc.get_o_indexes(self.output.absolute.tx).await?[usize::from(self.output.absolute.o)];
     Ok(())
   }
 
-  pub async fn from(rpc: &Rpc, output: ReceivedOutput) -> Result<SpendableOutput, RpcError> {
+  pub async fn from<RPC: RpcConnection>(
+    rpc: &Rpc<RPC>,
+    output: ReceivedOutput,
+  ) -> Result<SpendableOutput, RpcError> {
     let mut output = SpendableOutput { output, global_index: 0 };
     output.refresh_global_index(rpc).await?;
     Ok(output)
@@ -408,9 +414,9 @@ impl Scanner {
   /// transactions is a dead giveaway for which transactions you successfully scanned. This
   /// function obtains the output indexes for the miner transaction, incrementing from there
   /// instead.
-  pub async fn scan(
+  pub async fn scan<RPC: RpcConnection>(
     &mut self,
-    rpc: &Rpc,
+    rpc: &Rpc<RPC>,
     block: &Block,
   ) -> Result<Vec<Timelocked<SpendableOutput>>, RpcError> {
     let mut index = rpc.get_o_indexes(block.miner_tx.hash()).await?[0];

coins/monero/src/wallet/send/mod.rs

@@ -33,7 +33,7 @@ use crate::{
     RctBase, RctPrunable, RctSignatures,
   },
   transaction::{Input, Output, Timelock, TransactionPrefix, Transaction},
-  rpc::{Rpc, RpcError},
+  rpc::{RpcError, RpcConnection, Rpc},
   wallet::{
     address::{Network, AddressSpec, MoneroAddress},
     ViewPair, SpendableOutput, Decoys, PaymentId, ExtraField, Extra, key_image_sort, uniqueness,
@@ -147,9 +147,9 @@ pub enum TransactionError {
   FrostError(FrostError),
 }
 
-async fn prepare_inputs<R: RngCore + CryptoRng>(
+async fn prepare_inputs<R: RngCore + CryptoRng, RPC: RpcConnection>(
   rng: &mut R,
-  rpc: &Rpc,
+  rpc: &Rpc<RPC>,
   ring_len: usize,
   inputs: &[SpendableOutput],
   spend: &Zeroizing<Scalar>,
@@ -663,10 +663,10 @@ impl SignableTransaction {
   }
 
   /// Sign this transaction.
-  pub async fn sign<R: RngCore + CryptoRng>(
+  pub async fn sign<R: RngCore + CryptoRng, RPC: RpcConnection>(
     mut self,
     rng: &mut R,
-    rpc: &Rpc,
+    rpc: &Rpc<RPC>,
     spend: &Zeroizing<Scalar>,
   ) -> Result<Transaction, TransactionError> {
     let mut images = Vec::with_capacity(self.inputs.len());

coins/monero/src/wallet/send/multisig.rs

@@ -30,7 +30,7 @@ use crate::{
     RctPrunable,
   },
   transaction::{Input, Transaction},
-  rpc::Rpc,
+  rpc::{RpcConnection, Rpc},
   wallet::{
     TransactionError, InternalPayment, SignableTransaction, Decoys, key_image_sort, uniqueness,
   },
@@ -74,9 +74,9 @@ pub struct TransactionSignatureMachine {
 impl SignableTransaction {
   /// Create a FROST signing machine out of this signable transaction.
   /// The height is the Monero blockchain height to synchronize around.
-  pub async fn multisig(
+  pub async fn multisig<RPC: RpcConnection>(
     self,
-    rpc: &Rpc,
+    rpc: &Rpc<RPC>,
     keys: ThresholdKeys<Ed25519>,
     mut transcript: RecommendedTranscript,
     height: usize,

coins/monero/tests/runner.rs

@@ -12,7 +12,7 @@ use tokio::sync::Mutex;
 
 use monero_serai::{
   random_scalar,
-  rpc::Rpc,
+  rpc::{HttpRpc, Rpc},
   wallet::{
     ViewPair, Scanner,
     address::{Network, AddressType, AddressSpec, AddressMeta, MoneroAddress},
@@ -38,7 +38,7 @@ pub fn random_address() -> (Scalar, ViewPair, MoneroAddress) {
 // TODO: Support transactions already on-chain
 // TODO: Don't have a side effect of mining blocks more blocks than needed under race conditions
 // TODO: mine as much as needed instead of default 10 blocks
-pub async fn mine_until_unlocked(rpc: &Rpc, addr: &str, tx_hash: [u8; 32]) {
+pub async fn mine_until_unlocked(rpc: &Rpc<HttpRpc>, addr: &str, tx_hash: [u8; 32]) {
   // mine until tx is in a block
   let mut height = rpc.get_height().await.unwrap();
   let mut found = false;
@@ -60,7 +60,7 @@ pub async fn mine_until_unlocked(rpc: &Rpc, addr: &str, tx_hash: [u8; 32]) {
 
 // Mines 60 blocks and returns an unlocked miner TX output.
 #[allow(dead_code)]
-pub async fn get_miner_tx_output(rpc: &Rpc, view: &ViewPair) -> SpendableOutput {
+pub async fn get_miner_tx_output(rpc: &Rpc<HttpRpc>, view: &ViewPair) -> SpendableOutput {
   let mut scanner = Scanner::from_view(view.clone(), Some(HashSet::new()));
 
   // Mine 60 blocks to unlock a miner TX
@@ -74,8 +74,8 @@ pub async fn get_miner_tx_output(rpc: &Rpc, view: &ViewPair) -> SpendableOutput
   scanner.scan(rpc, &block).await.unwrap().swap_remove(0).ignore_timelock().swap_remove(0)
 }
 
-pub async fn rpc() -> Rpc {
-  let rpc = Rpc::new("http://127.0.0.1:18081".to_string()).unwrap();
+pub async fn rpc() -> Rpc<HttpRpc> {
+  let rpc = HttpRpc::new("http://127.0.0.1:18081".to_string()).unwrap();
 
   // Only run once
   if rpc.get_height().await.unwrap() != 1 {

coins/monero/tests/send.rs

@@ -69,7 +69,7 @@ test!(
     },
   ),
   (
-    |rpc: Rpc, _, _, mut outputs: Vec<ReceivedOutput>| async move {
+    |rpc: Rpc<_>, _, _, mut outputs: Vec<ReceivedOutput>| async move {
       let change_view = ViewPair::new(
         &random_scalar(&mut OsRng) * &ED25519_BASEPOINT_TABLE,
         Zeroizing::new(random_scalar(&mut OsRng)),

coins/monero/tests/wallet2_compatibility.rs

@@ -19,7 +19,7 @@ use monero_rpc::{
 
 use monero_serai::{
   transaction::Transaction,
-  rpc::Rpc,
+  rpc::{HttpRpc, Rpc},
   wallet::{
     address::{Network, AddressSpec, SubaddressIndex, MoneroAddress},
     extra::{MAX_TX_EXTRA_NONCE_SIZE, Extra},
@@ -35,7 +35,7 @@ async fn make_integrated_address(payment_id: [u8; 8]) -> String {
     integrated_address: String,
   }
 
-  let rpc = Rpc::new("http://127.0.0.1:6061".to_string()).unwrap();
+  let rpc = HttpRpc::new("http://127.0.0.1:6061".to_string()).unwrap();
   let res = rpc
     .json_rpc_call::<IntegratedAddressResponse>(
       "make_integrated_address",
@@ -47,7 +47,7 @@ async fn make_integrated_address(payment_id: [u8; 8]) -> String {
   res.integrated_address
 }
 
-async fn initialize_rpcs() -> (WalletClient, Rpc, monero_rpc::monero::Address) {
+async fn initialize_rpcs() -> (WalletClient, Rpc<HttpRpc>, monero_rpc::monero::Address) {
   let wallet_rpc =
     monero_rpc::RpcClientBuilder::new().build("http://127.0.0.1:6061").unwrap().wallet();
   let daemon_rpc = runner::rpc().await;