Add support for RPC state_getReadProof (#106)

* Add support for RPC `state_getReadProof`

* Format code

* Add test

Cargo.toml

@@ -36,6 +36,7 @@ hex = "0.4.0"
 sp-rpc = { version = "2.0.0-alpha.7", package = "sp-rpc" }
 sp-core = { version = "2.0.0-alpha.7", package = "sp-core" }
 sp-transaction-pool = { version = "2.0.0-alpha.7", package = "sp-transaction-pool" }
+sc-rpc-api = { version = "0.8.0-alpha.7", package = "sc-rpc-api" }
 
 [dev-dependencies]
 async-std = { version = "1.5.0", features = ["attributes"] }

src/lib.rs

@@ -50,6 +50,7 @@ use codec::{
 };
 use futures::future;
 use jsonrpsee::client::Subscription;
+use sc_rpc_api::state::ReadProof;
 use sp_core::{
     storage::{
         StorageChangeSet,
@@ -263,6 +264,19 @@ impl<T: System, S, E> Client<T, S, E> {
         Ok(block)
     }
 
+    /// Get proof of storage entries at a specific block's state.
+    pub async fn read_proof<H>(
+        &self,
+        keys: Vec<StorageKey>,
+        hash: Option<H>,
+    ) -> Result<ReadProof<T::Hash>, Error>
+    where
+        H: Into<T::Hash> + 'static,
+    {
+        let proof = self.rpc.read_proof(keys, hash.map(|h| h.into())).await?;
+        Ok(proof)
+    }
+
     /// Create and submit an extrinsic and return corresponding Hash if successful
     pub async fn submit_extrinsic<X: Encode>(
         &self,
@@ -519,6 +533,10 @@ impl codec::Encode for Encoded {
 
 #[cfg(test)]
 mod tests {
+    use sp_core::storage::{
+        well_known_keys,
+        StorageKey,
+    };
     use sp_keyring::{
         AccountKeyring,
         Ed25519Keyring,
@@ -575,6 +593,23 @@ mod tests {
         client.block(block_hash).await.unwrap();
     }
 
+    #[async_std::test]
+    #[ignore] // requires locally running substrate node
+    async fn test_getting_read_proof() {
+        let client = test_client().await;
+        let block_hash = client.block_hash(None).await.unwrap();
+        client
+            .read_proof(
+                vec![
+                    StorageKey(well_known_keys::HEAP_PAGES.to_vec()),
+                    StorageKey(well_known_keys::EXTRINSIC_INDEX.to_vec()),
+                ],
+                block_hash,
+            )
+            .await
+            .unwrap();
+    }
+
     #[async_std::test]
     #[ignore] // requires locally running substrate node
     async fn test_state_total_issuance() {

src/rpc.rs

@@ -38,6 +38,7 @@ use jsonrpsee::{
 use num_traits::bounds::Bounded;
 
 use frame_metadata::RuntimeMetadataPrefixed;
+use sc_rpc_api::state::ReadProof;
 use serde::Serialize;
 use sp_core::{
     storage::{
@@ -230,6 +231,17 @@ impl<T: System> Rpc<T> {
         Ok(block)
     }
 
+    /// Get proof of storage entries at a specific block's state.
+    pub async fn read_proof(
+        &self,
+        keys: Vec<StorageKey>,
+        hash: Option<T::Hash>,
+    ) -> Result<ReadProof<T::Hash>, Error> {
+        let params = Params::Array(vec![to_json_value(keys)?, to_json_value(hash)?]);
+        let proof = self.client.request("state_getReadProof", params).await?;
+        Ok(proof)
+    }
+
     /// Fetch the runtime version
     pub async fn runtime_version(
         &self,