rpc: Enable ChainSpec for polkadot-parachain

cumulus/polkadot-parachain/Cargo.toml

@@ -77,6 +77,7 @@ sp-block-builder = { workspace = true, default-features = true }
 sp-keystore = { workspace = true, default-features = true }
 sc-chain-spec = { workspace = true, default-features = true }
 sc-rpc = { workspace = true, default-features = true }
+sc-rpc-spec-v2 = { workspace = true, default-features = true }
 sp-version = { workspace = true, default-features = true }
 sc-tracing = { workspace = true, default-features = true }
 sp-offchain = { workspace = true, default-features = true }

cumulus/polkadot-parachain/src/rpc.rs

@@ -28,6 +28,7 @@ use sc_rpc::{
 	dev::{Dev, DevApiServer},
 	DenyUnsafe,
 };
+use sc_rpc_spec_v2::chain_spec::{ChainSpec, ChainSpecApiServer};
 use std::{marker::PhantomData, sync::Arc};
 use substrate_frame_rpc_system::{System, SystemApiServer};
 use substrate_state_trie_migration_rpc::{StateMigration, StateMigrationApiServer};
@@ -41,6 +42,7 @@ pub(crate) trait BuildRpcExtensions<Client, Backend, Pool> {
 		client: Arc<Client>,
 		backend: Arc<Backend>,
 		pool: Arc<Pool>,
+		chain_spec: Box<dyn sc_chain_spec::ChainSpec>,
 	) -> sc_service::error::Result<RpcExtension>;
 }
 
@@ -60,6 +62,7 @@ where
 		_client: Arc<ParachainClient<RuntimeApi>>,
 		_backend: Arc<ParachainBackend>,
 		_pool: Arc<sc_transaction_pool::FullPool<Block, ParachainClient<RuntimeApi>>>,
+		_chain_spec: Box<dyn sc_chain_spec::ChainSpec>,
 	) -> sc_service::error::Result<RpcExtension> {
 		Ok(RpcExtension::new(()))
 	}
@@ -83,6 +86,7 @@ where
 		client: Arc<ParachainClient<RuntimeApi>>,
 		backend: Arc<ParachainBackend>,
 		pool: Arc<sc_transaction_pool::FullPool<Block, ParachainClient<RuntimeApi>>>,
+		chain_spec: Box<dyn sc_chain_spec::ChainSpec>,
 	) -> sc_service::error::Result<RpcExtension> {
 		let build = || -> Result<RpcExtension, Box<dyn std::error::Error + Send + Sync>> {
 			let mut module = RpcExtension::new(());
@@ -92,6 +96,12 @@ where
 			module.merge(StateMigration::new(client.clone(), backend, deny_unsafe).into_rpc())?;
 			module.merge(Dev::new(client, deny_unsafe).into_rpc())?;
 
+			// RPC spec v2 method.
+			let chain_name = chain_spec.name().to_string();
+			let genesis_hash = client.hash(0).ok().flatten().expect("Genesis block exists; qed");
+			let properties = chain_spec.properties();
+			module.merge(ChainSpec::new(chain_name, genesis_hash, properties).into_rpc())?;
+
 			Ok(module)
 		};
 		build().map_err(Into::into)

cumulus/polkadot-parachain/src/service.rs

@@ -255,6 +255,7 @@ pub(crate) trait NodeSpec {
 
 			let validator = parachain_config.role.is_authority();
 			let prometheus_registry = parachain_config.prometheus_registry().cloned();
+			let chain_spec = parachain_config.chain_spec.cloned();
 			let transaction_pool = params.transaction_pool.clone();
 			let import_queue_service = params.import_queue.service();
 			let net_config = FullNetworkConfiguration::<_, _, Net>::new(
@@ -281,12 +282,13 @@ pub(crate) trait NodeSpec {
 				let transaction_pool = transaction_pool.clone();
 				let backend_for_rpc = backend.clone();
 
-				Box::new(move |deny_unsafe, _| {
+				Box::new(move |deny_unsafe: sc_rpc::DenyUnsafe, _| {
 					Self::BuildRpcExtensions::build_rpc_extensions(
 						deny_unsafe,
 						client.clone(),
 						backend_for_rpc.clone(),
 						transaction_pool.clone(),
+						chain_spec,
 					)
 				})
 			};

prdoc/pr_5205.prdoc

@@ -0,0 +1,16 @@
+title: Enable ChainSpec API for polkadot-parachain
+
+doc:
+  - audience:
+    - Runtime Dev
+    - Node Dev
+    description: |
+      Enables the `chainSpec_v1` rpc-v2 API for polkadot-parachains.
+      This RPC is needed to provide extra information about the specification of the chain.
+      At the same time, this paves the way for implementing in the future a `chainSpec_v1_getSpec`
+      method that can extract the chainSpec of any chain (including parachains) for the use with lightclients.
+      For more info about the `chainSpec`, please see the specification: https://github.com/paritytech/json-rpc-interface-spec/blob/main/src/api/chainSpec.md.
+
+crates: 
+  - name: polkadot-parachain-bin
+    bump: minor