Add archive RPCs to subxt-rpcs (#1940)

* Add archive RPCs to subxt-rpcs

* Add tests for archive RPCs

* ".unwrap_*" to ".as_*"

* clippy

* Add proper unsub method for archive_unstable_storage

rpcs/src/methods/chain_head.rs

@@ -179,7 +179,7 @@ impl<T: RpcConfig> ChainHeadRpcMethods<T> {
         Ok(response)
     }
 
-    /// Call the `chainHead_v1_storage` method and return an operation ID to obtain the runtime API result.
+    /// Call the `chainHead_v1_call` method and return an operation ID to obtain the runtime API result.
     ///
     /// The response events are provided on the `chainHead_follow` subscription and identified by
     /// the returned operation ID.
@@ -224,20 +224,16 @@ impl<T: RpcConfig> ChainHeadRpcMethods<T> {
 
     /// Return the genesis hash.
     pub async fn chainspec_v1_genesis_hash(&self) -> Result<T::Hash, Error> {
-        let hash = self
-            .client
+        self.client
             .request("chainSpec_v1_genesisHash", rpc_params![])
-            .await?;
-        Ok(hash)
+            .await
     }
 
     /// Return a string containing the human-readable name of the chain.
     pub async fn chainspec_v1_chain_name(&self) -> Result<String, Error> {
-        let hash = self
-            .client
+        self.client
             .request("chainSpec_v1_chainName", rpc_params![])
-            .await?;
-        Ok(hash)
+            .await
     }
 
     /// Returns the JSON payload found in the chain specification under the key properties.
@@ -295,6 +291,132 @@ impl<T: RpcConfig> ChainHeadRpcMethods<T> {
             .request("transaction_v1_stop", rpc_params![operation_id])
             .await
     }
+
+    /// Fetch the block body (ie the extrinsics in the block) given its hash.
+    ///
+    /// Returns an array of the hexadecimal-encoded scale-encoded extrinsics found in the block,
+    /// or `None` if the block wasn't found.
+    pub async fn archive_unstable_body(
+        &self,
+        block_hash: T::Hash,
+    ) -> Result<Option<Vec<Bytes>>, Error> {
+        self.client
+            .request("archive_unstable_body", rpc_params![block_hash])
+            .await
+    }
+
+    /// Call the `archive_unstable_call` method and return the response.
+    pub async fn archive_unstable_call(
+        &self,
+        block_hash: T::Hash,
+        function: &str,
+        call_parameters: &[u8],
+    ) -> Result<ArchiveCallResult, Error> {
+        use serde::de::Error as _;
+
+        // We deserialize to this intermediate shape, since
+        // we can't have a boolean tag to denote variants.
+        #[derive(Deserialize)]
+        struct Response {
+            success: bool,
+            value: Option<Bytes>,
+            error: Option<String>,
+            // This was accidentally used instead of value in Substrate,
+            // so to support those impls we try it here if needed:
+            result: Option<Bytes>,
+        }
+
+        let res: Response = self
+            .client
+            .request(
+                "archive_unstable_call",
+                rpc_params![block_hash, function, to_hex(call_parameters)],
+            )
+            .await?;
+
+        let value = res.value.or(res.result);
+        match (res.success, value, res.error) {
+            (true, Some(value), _) => Ok(ArchiveCallResult::Success(value)),
+            (false, _, err) => Ok(ArchiveCallResult::Error(err.unwrap_or(String::new()))),
+            (true, None, _) => {
+                let m = "archive_unstable_call: 'success: true' response should have `value: 0x1234` alongside it";
+                Err(Error::Deserialization(serde_json::Error::custom(m)))
+            }
+        }
+    }
+
+    /// Return the finalized block height of the chain.
+    pub async fn archive_unstable_finalized_height(&self) -> Result<usize, Error> {
+        self.client
+            .request("archive_unstable_finalizedHeight", rpc_params![])
+            .await
+    }
+
+    /// Return the genesis hash.
+    pub async fn archive_unstable_genesis_hash(&self) -> Result<T::Hash, Error> {
+        self.client
+            .request("archive_unstable_genesisHash", rpc_params![])
+            .await
+    }
+
+    /// Given a block height, return the hashes of the zero or more blocks at that height.
+    /// For blocks older than the latest finalized block, only one entry will be returned. For blocks
+    /// newer than the latest finalized block, it's possible to have 0, 1 or multiple blocks at
+    /// that height given that forks could occur.
+    pub async fn archive_unstable_hash_by_height(
+        &self,
+        height: usize,
+    ) -> Result<Vec<T::Hash>, Error> {
+        self.client
+            .request("archive_unstable_hashByHeight", rpc_params![height])
+            .await
+    }
+
+    /// Fetch the header for a block with the given hash, or `None` if no block with that hash exists.
+    pub async fn archive_unstable_header(
+        &self,
+        block_hash: T::Hash,
+    ) -> Result<Option<T::Header>, Error> {
+        let maybe_encoded_header: Option<Bytes> = self
+            .client
+            .request("archive_unstable_header", rpc_params![block_hash])
+            .await?;
+
+        let Some(encoded_header) = maybe_encoded_header else {
+            return Ok(None);
+        };
+
+        let header =
+            <T::Header as codec::Decode>::decode(&mut &*encoded_header.0).map_err(Error::Decode)?;
+        Ok(Some(header))
+    }
+
+    /// Query the node storage and return a subscription which streams corresponding storage events back.
+    pub async fn archive_unstable_storage(
+        &self,
+        block_hash: T::Hash,
+        items: impl IntoIterator<Item = StorageQuery<&[u8]>>,
+        child_key: Option<&[u8]>,
+    ) -> Result<ArchiveStorageSubscription<T::Hash>, Error> {
+        let items: Vec<StorageQuery<String>> = items
+            .into_iter()
+            .map(|item| StorageQuery {
+                key: to_hex(item.key),
+                query_type: item.query_type,
+            })
+            .collect();
+
+        let sub = self
+            .client
+            .subscribe(
+                "archive_unstable_storage",
+                rpc_params![block_hash, items, child_key.map(to_hex)],
+                "archive_unstable_stopStorage",
+            )
+            .await?;
+
+        Ok(ArchiveStorageSubscription { sub, done: false })
+    }
 }
 
 /// This represents events generated by the `follow` method.
@@ -754,6 +876,140 @@ pub struct TransactionBlockDetails<Hash> {
     pub index: u64,
 }
 
+/// The response from calling `archive_call`.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum ArchiveCallResult {
+    /// The bytes returned from successfully making a call
+    Success(Bytes),
+    /// An error returned if the call was not successful.
+    Error(String),
+}
+
+impl ArchiveCallResult {
+    /// Return the bytes on success, or `None` if not an [`ArchiveCallResult::Success`].
+    pub fn as_success(self) -> Option<Bytes> {
+        match self {
+            ArchiveCallResult::Success(bytes) => Some(bytes),
+            _ => None,
+        }
+    }
+
+    /// Return the error message on call failure, or `None` if not an [`ArchiveCallResult::Error`].
+    pub fn as_error(self) -> Option<String> {
+        match self {
+            ArchiveCallResult::Success(_) => None,
+            ArchiveCallResult::Error(e) => Some(e),
+        }
+    }
+}
+
+/// A subscription which returns follow events, and ends when a Stop event occurs.
+pub struct ArchiveStorageSubscription<Hash> {
+    sub: RpcSubscription<ArchiveStorageEvent<Hash>>,
+    done: bool,
+}
+
+impl<Hash: BlockHash> ArchiveStorageSubscription<Hash> {
+    /// Fetch the next item in the stream.
+    pub async fn next(&mut self) -> Option<<Self as Stream>::Item> {
+        <Self as StreamExt>::next(self).await
+    }
+    /// Fetch the subscription ID for the stream.
+    pub fn subscription_id(&self) -> Option<&str> {
+        self.sub.subscription_id()
+    }
+}
+
+impl<Hash: BlockHash> Stream for ArchiveStorageSubscription<Hash> {
+    type Item = <RpcSubscription<ArchiveStorageEvent<Hash>> as Stream>::Item;
+    fn poll_next(
+        mut self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Option<Self::Item>> {
+        if self.done {
+            return Poll::Ready(None);
+        }
+
+        let res = self.sub.poll_next_unpin(cx);
+
+        if let Poll::Ready(Some(Ok(ArchiveStorageEvent::Done | ArchiveStorageEvent::Error(..)))) =
+            &res
+        {
+            // No more events will occur after "done" or "error" events.
+            self.done = true;
+        }
+
+        res
+    }
+}
+
+/// Responses returned from [`ArchiveStorageSubscription`].
+#[derive(Debug, Deserialize)]
+#[serde(tag = "event")]
+pub enum ArchiveStorageEvent<Hash> {
+    /// A storage response for one of the requested items.
+    #[serde(rename = "storage")]
+    Item(ArchiveStorageEventItem<Hash>),
+    /// A human-readable error indicating what went wrong. No more storage events
+    /// will be emitted after this.
+    #[serde(rename = "storageError")]
+    Error(ArchiveStorageEventError),
+    /// No more storage events will be emitted after this.
+    #[serde(rename = "storageDone")]
+    Done,
+}
+
+impl<Hash> ArchiveStorageEvent<Hash> {
+    /// Return a storage item or `None` if not an [`ArchiveStorageEvent::Item`].
+    pub fn as_item(self) -> Option<ArchiveStorageEventItem<Hash>> {
+        match self {
+            ArchiveStorageEvent::Item(item) => Some(item),
+            _ => None,
+        }
+    }
+
+    /// Return a storage error or `None` if not an [`ArchiveStorageEvent::Error`].
+    pub fn as_error(self) -> Option<ArchiveStorageEventError> {
+        match self {
+            ArchiveStorageEvent::Error(e) => Some(e),
+            _ => None,
+        }
+    }
+
+    /// Is this an [`ArchiveStorageEvent::Done`].
+    pub fn is_done(self) -> bool {
+        matches!(self, ArchiveStorageEvent::Done)
+    }
+}
+
+/// Something went wrong during the [`ChainHeadRpcMethods::archive_unstable_storage()`] subscription.
+#[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ArchiveStorageEventError {
+    /// The human readable error message indicating what went wrong.
+    pub error: String,
+}
+
+/// A storage item returned from the [`ChainHeadRpcMethods::archive_unstable_storage()`] subscription.
+#[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ArchiveStorageEventItem<Hash> {
+    /// String containing the hexadecimal-encoded key of the storage entry.
+    pub key: Bytes,
+    /// String containing the hexadecimal-encoded value of the storage entry.
+    /// Returned when the request type is [`StorageQueryType::Value`] or [`StorageQueryType::DescendantsValues`].
+    pub value: Option<Bytes>,
+    /// String containing the hexadecimal-encoded hash of the storage entry.
+    /// Returned when the request type is [`StorageQueryType::Hash`] or [`StorageQueryType::DescendantsHashes`].
+    pub hash: Option<Hash>,
+    /// String containing the hexadecimal-encoded Merkle value of the closest descendant of key (including branch nodes).
+    /// Returned when the request type is [`StorageQueryType::ClosestDescendantMerkleValue`].
+    pub closest_descendant_merkle_value: Option<Bytes>,
+    /// String containing the hexadecimal-encoded key of the child trie of the "default" namespace if the storage entry
+    /// is part of a child trie. If the storage entry is part of the main trie, this field is not present.
+    pub child_trie_key: Option<Bytes>,
+}
+
 /// Hex-serialized shim for `Vec<u8>`.
 #[derive(PartialEq, Eq, Clone, Serialize, Deserialize, Hash, PartialOrd, Ord, Debug)]
 pub struct Bytes(#[serde(with = "impl_serde::serialize")] pub Vec<u8>);