rpc: Implement transaction RPC API

client/rpc-spec-v2/Cargo.toml

@@ -16,7 +16,17 @@ targets = ["x86_64-unknown-linux-gnu"]
 jsonrpsee = { version = "0.15.1", features = ["server", "macros"] }
 # Internal chain structures for "chain_spec".
 sc-chain-spec = { version = "4.0.0-dev", path = "../chain-spec" }
+# Pool for submitting extrinsics required by "transaction"
+sc-transaction-pool-api = { version = "4.0.0-dev", path = "../transaction-pool/api" }
+sp-core = { version = "6.0.0", path = "../../primitives/core" }
+sp-runtime = { version = "6.0.0", path = "../../primitives/runtime" }
+sp-api = { version = "4.0.0-dev", path = "../../primitives/api" }
+sp-blockchain = { version = "4.0.0-dev", path = "../../primitives/blockchain" }
+codec = { package = "parity-scale-codec", version = "3.0.0" }
+thiserror = "1.0"
+serde = "1.0"
 hex = "0.4"
+futures = "0.3.21"
 
 [dev-dependencies]
 serde_json = "1.0"

client/rpc-spec-v2/src/lib.rs

@@ -24,3 +24,7 @@
 #![deny(unused_crate_dependencies)]
 
 pub mod chain_spec;
+pub mod transaction;
+
+/// Task executor that is being used by RPC subscriptions.
+pub type SubscriptionTaskExecutor = std::sync::Arc<dyn sp_core::traits::SpawnNamed>;

client/rpc-spec-v2/src/transaction/api.rs

@@ -0,0 +1,38 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2022 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! API trait for transactions.
+
+use crate::transaction::event::TransactionEvent;
+use jsonrpsee::proc_macros::rpc;
+use sp_core::Bytes;
+
+#[rpc(client, server)]
+// This trait bound is required by serde, see `event`.
+pub trait TransactionApi<Hash: Clone> {
+	/// Submit an extrinsic to watch.
+	///
+	/// See [`TransactionEvent`](crate::transaction::event::TransactionEvent) for details on
+	/// transaction life cycle.
+	#[subscription(
+		name = "transaction_unstable_submitAndWatch" => "transaction_unstable_submitExtrinsic",
+		unsubscribe = "transaction_unstable_unwatch",
+		item = TransactionEvent<Hash>,
+	)]
+	fn submit_and_watch(&self, bytes: Bytes);
+}

client/rpc-spec-v2/src/transaction/error.rs

@@ -0,0 +1,100 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2022 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Transaction RPC errors.
+//!
+//! Errors are interpreted as transaction events for subscriptions.
+
+use crate::transaction::event::{TransactionError, TransactionEvent};
+use sc_transaction_pool_api::error::Error as PoolError;
+use sp_runtime::transaction_validity::InvalidTransaction;
+
+/// Transaction RPC errors.
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+	/// Transaction pool error.
+	#[error("Transaction pool error: {}", .0)]
+	Pool(#[from] PoolError),
+	/// Verification error.
+	#[error("Extrinsic verification error: {}", .0)]
+	Verification(Box<dyn std::error::Error + Send + Sync>),
+}
+
+impl<Hash> From<Error> for TransactionEvent<Hash> {
+	fn from(e: Error) -> Self {
+		match e {
+			Error::Verification(e) => TransactionEvent::Invalid(TransactionError {
+				error: format!("Verification error: {}", e),
+			}),
+			Error::Pool(PoolError::InvalidTransaction(InvalidTransaction::Custom(e))) =>
+				TransactionEvent::Invalid(TransactionError {
+					error: format!("Invalid transaction with custom error: {}", e),
+				}),
+			Error::Pool(PoolError::InvalidTransaction(e)) => {
+				let msg: &str = e.into();
+				TransactionEvent::Invalid(TransactionError {
+					error: format!("Invalid transaction: {}", msg),
+				})
+			},
+			Error::Pool(PoolError::UnknownTransaction(e)) => {
+				let msg: &str = e.into();
+				TransactionEvent::Invalid(TransactionError {
+					error: format!("Unknown transaction validity: {}", msg),
+				})
+			},
+			Error::Pool(PoolError::TemporarilyBanned) =>
+				TransactionEvent::Invalid(TransactionError {
+					error: "Transaction is temporarily banned".into(),
+				}),
+			Error::Pool(PoolError::AlreadyImported(_)) =>
+				TransactionEvent::Invalid(TransactionError {
+					error: "Transaction is already imported".into(),
+				}),
+			Error::Pool(PoolError::TooLowPriority { old, new }) =>
+				TransactionEvent::Invalid(TransactionError {
+					error: format!(
+						"The priority of the transactin is too low (pool {} > current {})",
+						old, new
+					),
+				}),
+			Error::Pool(PoolError::CycleDetected) => TransactionEvent::Invalid(TransactionError {
+				error: "The transaction contains a cyclic dependency".into(),
+			}),
+			Error::Pool(PoolError::ImmediatelyDropped) =>
+				TransactionEvent::Invalid(TransactionError {
+					error: "The transaction could not enter the pool because of the limit".into(),
+				}),
+			Error::Pool(PoolError::Unactionable) => TransactionEvent::Invalid(TransactionError {
+				error: "Transaction cannot be propagated and the local node does not author blocks"
+					.into(),
+			}),
+			Error::Pool(PoolError::NoTagsProvided) => TransactionEvent::Invalid(TransactionError {
+				error: "Transaction does not provide any tags, so the pool cannot identify it"
+					.into(),
+			}),
+			Error::Pool(PoolError::InvalidBlockId(_)) =>
+				TransactionEvent::Invalid(TransactionError {
+					error: "The provided block ID is not valid".into(),
+				}),
+			Error::Pool(PoolError::RejectedFutureTransaction) =>
+				TransactionEvent::Invalid(TransactionError {
+					error: "The pool is not accepting future transactions".into(),
+				}),
+		}
+	}
+}