Add method to fetch a block's events to the RPC

substrate/node/src/rpc/blockchain.rs

@@ -11,27 +11,20 @@ use sc_client_api::BlockBackend;
 
 use serai_abi::{primitives::prelude::*, SubstrateBlock as Block};
 
+use serai_runtime::SeraiApi;
+
 use jsonrpsee::RpcModule;
 
-pub(crate) fn module<
-  C: 'static
-    + Send
-    + Sync
-    + HeaderMetadata<Block, Error = BlockchainError>
+fn block_hash<
+  C: 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_method("serai_latestFinalizedBlockNumber", |_params, client, _ext| {
-    client.info().finalized_number
-  });
-
-  module.register_method("serai_isFinalized", |params, client, _ext| {
-    let [block_hash]: [String; 1] = params.parse()?;
+  client: &C,
+  params: &jsonrpsee::types::params::Params,
+) -> Result<<Block as sp_runtime::traits::Block>::Hash, jsonrpsee::types::error::ErrorObjectOwned> {
+  Ok(if let Ok(block_hash) = params.sequence().next::<String>() {
     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)
@@ -43,6 +36,45 @@ pub(crate) fn module<
         Option::<()>::None,
       ));
     };
+    block_hash
+  } else {
+    let Ok(block_number) = params.sequence().next::<u64>() else {
+      return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
+        -1,
+        "requested block wasn't a valid hash nor number",
+        Option::<()>::None,
+      ));
+    };
+    let Ok(Some(block_hash)) = client.block_hash(block_number) else {
+      return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
+        -2,
+        "couldn't find requested block's hash",
+        Option::<()>::None,
+      ));
+    };
+    block_hash
+  })
+}
+
+pub(crate) fn module<
+  C: 'static
+    + Send
+    + Sync
+    + HeaderMetadata<Block, Error = BlockchainError>
+    + HeaderBackend<Block>
+    + BlockBackend<Block>
+    + ProvideRuntimeApi<Block, Api: SeraiApi<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_method("serai_latestFinalizedBlockNumber", |_params, client, _ext| {
+    client.info().finalized_number
+  });
+
+  module.register_method("serai_isFinalized", |params, client, _ext| {
+    let block_hash = block_hash(&**client, &params)?;
     let finalized = client.info().finalized_number;
     let Ok(Some(number)) = client.number(block_hash) else {
       return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
@@ -65,37 +97,7 @@ pub(crate) fn module<
   })?;
 
   module.register_method("serai_block", |params, client, _ext| {
-    let block_hash = if let Ok([block_hash]) = params.parse::<[String; 1]>() {
-      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,
-        ));
-      };
-      block_hash
-    } else {
-      let Ok([block_number]) = params.parse::<[u64; 1]>() else {
-        return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
-          -1,
-          "requested block wasn't a valid hash nor number",
-          Option::<()>::None,
-        ));
-      };
-      let Ok(Some(block_hash)) = client.block_hash(block_number) else {
-        return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
-          -2,
-          "couldn't find requested block's hash",
-          Option::<()>::None,
-        ));
-      };
-      block_hash
-    };
-
+    let block_hash = block_hash(&**client, &params)?;
     let Ok(Some(block)) = client.block(block_hash) else {
       return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
         -2,
@@ -107,5 +109,17 @@ pub(crate) fn module<
     Ok(hex::encode(borsh::to_vec(&serai_abi::Block::from(block.block)).unwrap()))
   })?;
 
+  module.register_method("serai_events", |params, client, _ext| {
+    let block_hash = block_hash(&**client, &params)?;
+    let Ok(events) = client.runtime_api().events(block_hash) else {
+      return Err(jsonrpsee::types::error::ErrorObjectOwned::owned(
+        -2,
+        "couldn't fetch the events for the requested block",
+        Option::<()>::None,
+      ));
+    };
+    Ok(events.into_iter().map(hex::encode).collect::<Vec<String>>())
+  })?;
+
   Ok(module)
 }