Send initial values with subscription.

substrate/client/src/client.rs

@@ -568,7 +568,7 @@ mod tests {
 	use test_client::{self, TestClient};
 	use test_client::client::BlockOrigin;
 	use test_client::client::backend::Backend as TestBackend;
-	use test_client::runtime as test_runtime;
+	use test_client::{runtime as test_runtime, BlockBuilderExt};
 	use test_client::runtime::{Transfer, Extrinsic};
 
 	#[test]
@@ -602,23 +602,18 @@ mod tests {
 		assert_eq!(client.info().unwrap().chain.best_number, 1);
 	}
 
-	fn sign_tx(tx: Transfer) -> Extrinsic {
-		let signature = Keyring::from_raw_public(tx.from.0.clone()).unwrap().sign(&tx.encode()).into();
-		Extrinsic { transfer: tx, signature }
-	}
-
 	#[test]
 	fn block_builder_works_with_transactions() {
 		let client = test_client::new();
 
 		let mut builder = client.new_block().unwrap();
 
-		builder.push(sign_tx(Transfer {
+		builder.push_transfer(Transfer {
 			from: Keyring::Alice.to_raw_public().into(),
 			to: Keyring::Ferdie.to_raw_public().into(),
 			amount: 42,
 			nonce: 0,
-		})).unwrap();
+		}).unwrap();
 
 		client.justify_and_import(BlockOrigin::Own, builder.bake().unwrap()).unwrap();
 
@@ -646,19 +641,19 @@ mod tests {
 
 		let mut builder = client.new_block().unwrap();
 
-		builder.push(sign_tx(Transfer {
+		builder.push_transfer(Transfer {
 			from: Keyring::Alice.to_raw_public().into(),
 			to: Keyring::Ferdie.to_raw_public().into(),
 			amount: 42,
 			nonce: 0,
-		})).unwrap();
+		}).unwrap();
 
-		assert!(builder.push(sign_tx(Transfer {
+		assert!(builder.push_transfer(Transfer {
 			from: Keyring::Eve.to_raw_public().into(),
 			to: Keyring::Alice.to_raw_public().into(),
 			amount: 42,
 			nonce: 0,
-		})).is_err());
+		}).is_err());
 
 		client.justify_and_import(BlockOrigin::Own, builder.bake().unwrap()).unwrap();
 

substrate/client/src/notifications.rs

@@ -103,6 +103,11 @@ impl<Block: BlockT> StorageNotifications<Block> {
 			}
 		}
 
+		// Don't send empty notifications
+		if changes.is_empty() {
+			return;
+		}
+
 		let changes = Arc::new(changes);
 		// Trigger the events
 		for subscriber in subscribers {
@@ -264,4 +269,21 @@ mod tests {
 		assert_eq!(notifications.listeners.len(), 0);
 		assert_eq!(notifications.wildcard_listeners.len(), 0);
 	}
+
+	#[test]
+	fn should_not_send_empty_notifications() {
+		// given
+		let mut recv = {
+			let mut notifications = StorageNotifications::<Block>::default();
+			let recv = notifications.listen(None).wait();
+
+			// when
+			let changeset = vec![];
+			notifications.trigger(&1.into(), changeset.into_iter());
+			recv
+		};
+
+		// then
+		assert_eq!(recv.next(), None);
+	}
 }

substrate/rpc/Cargo.toml

@@ -22,3 +22,4 @@ tokio = "0.1.7"
 [dev-dependencies]
 assert_matches = "1.1"
 substrate-test-client = { path = "../test-client" }
+rustc-hex = "2.0"

substrate/rpc/src/chain/error.rs

@@ -14,11 +14,15 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
+use client;
 use rpc;
 
 use errors;
 
 error_chain! {
+	links {
+		Client(client::error::Error, client::error::ErrorKind) #[doc = "Client error"];
+	}
 	errors {
 		/// Not implemented yet
 		Unimplemented {

substrate/rpc/src/chain/mod.rs

@@ -22,7 +22,7 @@ use client::{self, Client, BlockchainEvents};
 use jsonrpc_macros::pubsub;
 use jsonrpc_pubsub::SubscriptionId;
 use rpc::Result as RpcResult;
-use rpc::futures::{Future, Sink, Stream};
+use rpc::futures::{stream, Future, Sink, Stream};
 use runtime_primitives::generic::BlockId;
 use runtime_primitives::traits::Block as BlockT;
 use tokio::runtime::TaskExecutor;
@@ -33,7 +33,7 @@ mod error;
 #[cfg(test)]
 mod tests;
 
-use self::error::{Result, ResultExt};
+use self::error::Result;
 
 build_rpc_trait! {
 	/// Polkadot blockchain API
@@ -86,22 +86,35 @@ impl<B, E, Block> ChainApi<Block::Hash, Block::Header> for Chain<B, E, Block> wh
 	type Metadata = ::metadata::Metadata;
 
 	fn header(&self, hash: Block::Hash) -> Result<Option<Block::Header>> {
-		self.client.header(&BlockId::Hash(hash)).chain_err(|| "Blockchain error")
+		Ok(self.client.header(&BlockId::Hash(hash))?)
 	}
 
 	fn head(&self) -> Result<Block::Hash> {
-		Ok(self.client.info().chain_err(|| "Blockchain error")?.chain.best_hash)
+		Ok(self.client.info()?.chain.best_hash)
 	}
 
 	fn subscribe_new_head(&self, _metadata: Self::Metadata, subscriber: pubsub::Subscriber<Block::Header>) {
 		self.subscriptions.add(subscriber, |sink| {
+			// send current head right at the start.
+			let header = self.head()
+				.and_then(|hash| self.header(hash))
+				.and_then(|header| {
+					header.ok_or_else(|| self::error::ErrorKind::Unimplemented.into())
+				})
+				.map_err(Into::into);
+
+			// send further subscriptions
 			let stream = self.client.import_notification_stream()
 				.filter(|notification| notification.is_new_best)
 				.map(|notification| Ok(notification.header))
 				.map_err(|e| warn!("Block notification stream error: {:?}", e));
+
 			sink
 				.sink_map_err(|e| warn!("Error sending notifications: {:?}", e))
-				.send_all(stream)
+				.send_all(
+					stream::iter_result(vec![Ok(header)])
+						.chain(stream)
+				)
 				// we ignore the resulting Stream (if the first stream is over we are unsubscribed)
 				.map(|_| ())
 		});

substrate/rpc/src/chain/tests.rs

@@ -67,9 +67,12 @@ fn should_notify_about_latest_block() {
 		api.client.justify_and_import(BlockOrigin::Own, builder.bake().unwrap()).unwrap();
 	}
 
-	// assert notification send to transport
+	// assert initial head sent.
 	let (notification, next) = core.block_on(transport.into_future()).unwrap();
 	assert!(notification.is_some());
+	// assert notification sent to transport
+	let (notification, next) = core.block_on(next.into_future()).unwrap();
+	assert!(notification.is_some());
 	// no more notifications on this channel
 	assert_eq!(core.block_on(next.into_future()).unwrap().0, None);
 }

substrate/rpc/src/lib.rs

@@ -41,6 +41,8 @@ extern crate log;
 extern crate assert_matches;
 #[cfg(test)]
 extern crate substrate_test_client as test_client;
+#[cfg(test)]
+extern crate rustc_hex;
 
 mod errors;
 mod subscriptions;

substrate/rpc/src/state/mod.rs

@@ -25,7 +25,7 @@ use jsonrpc_pubsub::SubscriptionId;
 use primitives::hexdisplay::HexDisplay;
 use primitives::storage::{StorageKey, StorageData, StorageChangeSet};
 use rpc::Result as RpcResult;
-use rpc::futures::{Future, Sink, Stream};
+use rpc::futures::{stream, Future, Sink, Stream};
 use runtime_primitives::generic::BlockId;
 use runtime_primitives::traits::Block as BlockT;
 use tokio::runtime::TaskExecutor;
@@ -141,6 +141,7 @@ impl<B, E, Block> StateApi<Block::Hash> for State<B, E, Block> where
 
 	fn storage(&self, key: StorageKey) -> Result<StorageData> {
 		self.storage_at(key, self.client.info()?.chain.best_hash)
+
 	}
 
 	fn call(&self, method: String, data: Vec<u8>) -> Result<Vec<u8>> {
@@ -162,16 +163,31 @@ impl<B, E, Block> StateApi<Block::Hash> for State<B, E, Block> where
 			},
 		};
 
+		// initial values
+		let initial = stream::iter_result(keys
+			.map(|keys| {
+				let changes = keys
+					.into_iter()
+					.map(|key| self.storage(key.clone())
+						.map(|val| (key.clone(), Some(val)))
+						.unwrap_or_else(|_| (key, None))
+					)
+					.collect();
+				let block = self.client.info().map(|info| info.chain.best_hash).unwrap_or_default();
+				vec![Ok(Ok(StorageChangeSet { block, changes }))]
+			}).unwrap_or_default());
+
 		self.subscriptions.add(subscriber, |sink| {
 			let stream = stream
 				.map_err(|e| warn!("Error creating storage notification stream: {:?}", e))
 				.map(|(block, changes)| Ok(StorageChangeSet {
 					block,
 					changes: changes.iter().cloned().collect(),
 				}));
+
 			sink
 				.sink_map_err(|e| warn!("Error sending notifications: {:?}", e))
-				.send_all(stream)
+				.send_all(initial.chain(stream))
 				// we ignore the resulting Stream (if the first stream is over we are unsubscribed)
 				.map(|_| ())
 		})

substrate/rpc/src/state/tests.rs

@@ -16,9 +16,12 @@
 
 use super::*;
 use self::error::{Error, ErrorKind};
-use jsonrpc_macros::pubsub;
+
 use client::BlockOrigin;
-use test_client::{self, TestClient};
+use jsonrpc_macros::pubsub;
+use rustc_hex::FromHex;
+use test_client::{self, runtime, keyring::Keyring, TestClient, BlockBuilderExt};
+
 
 #[test]
 fn should_return_storage() {
@@ -63,13 +66,58 @@ fn should_notify_about_storage_changes() {
 		// assert id assigned
 		assert_eq!(core.block_on(id), Ok(Ok(SubscriptionId::Number(0))));
 
-		let builder = api.client.new_block().unwrap();
+		let mut builder = api.client.new_block().unwrap();
+		builder.push_transfer(runtime::Transfer {
+			from: Keyring::Alice.to_raw_public().into(),
+			to: Keyring::Ferdie.to_raw_public().into(),
+			amount: 42,
+			nonce: 0,
+		}).unwrap();
 		api.client.justify_and_import(BlockOrigin::Own, builder.bake().unwrap()).unwrap();
 	}
 
-	// assert notification send to transport
+	// assert notification sent to transport
 	let (notification, next) = core.block_on(transport.into_future()).unwrap();
 	assert!(notification.is_some());
 	// no more notifications on this channel
 	assert_eq!(core.block_on(next.into_future()).unwrap().0, None);
 }
+
+#[test]
+fn should_send_initial_storage_changes_and_notifications() {
+	let mut core = ::tokio::runtime::Runtime::new().unwrap();
+	let remote = core.executor();
+	let (subscriber, id, transport) = pubsub::Subscriber::new_test("test");
+
+	{
+		let api = State {
+			client: Arc::new(test_client::new()),
+			subscriptions: Subscriptions::new(remote),
+		};
+
+		api.subscribe_storage(Default::default(), subscriber, Some(vec![
+			StorageKey("a52da2b7c269da1366b3ed1cdb7299ce".from_hex().unwrap()),
+		]).into());
+
+		// assert id assigned
+		assert_eq!(core.block_on(id), Ok(Ok(SubscriptionId::Number(0))));
+
+		let mut builder = api.client.new_block().unwrap();
+		builder.push_transfer(runtime::Transfer {
+			from: Keyring::Alice.to_raw_public().into(),
+			to: Keyring::Ferdie.to_raw_public().into(),
+			amount: 42,
+			nonce: 0,
+		}).unwrap();
+		api.client.justify_and_import(BlockOrigin::Own, builder.bake().unwrap()).unwrap();
+	}
+
+	// assert initial values sent to transport
+	let (notification, next) = core.block_on(transport.into_future()).unwrap();
+	assert!(notification.is_some());
+	// assert notification sent to transport
+	let (notification, next) = core.block_on(next.into_future()).unwrap();
+	assert!(notification.is_some());
+	// no more notifications on this channel
+	assert_eq!(core.block_on(next.into_future()).unwrap().0, None);
+}

substrate/test-client/src/block_builder_ext.rs

@@ -0,0 +1,41 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Block Builder extensions for tests.
+
+use codec;
+use client;
+use keyring;
+use runtime;
+
+use {Backend, Executor};
+
+/// Extension trait for test block builder.
+pub trait BlockBuilderExt {
+	/// Add transfer extrinsic to the block.
+	fn push_transfer(&mut self, transfer: runtime::Transfer) -> Result<(), client::error::Error>;
+}
+
+impl BlockBuilderExt for client::block_builder::BlockBuilder<Backend, Executor, runtime::Block> {
+	fn push_transfer(&mut self, transfer: runtime::Transfer) -> Result<(), client::error::Error> {
+		self.push(sign_tx(transfer))
+	}
+}
+
+fn sign_tx(transfer: runtime::Transfer) -> runtime::Extrinsic {
+	let signature = keyring::Keyring::from_raw_public(transfer.from.0.clone()).unwrap().sign(&codec::Encode::encode(&transfer)).into();
+	runtime::Extrinsic { transfer, signature }
+}

substrate/test-client/src/lib.rs

@@ -21,18 +21,20 @@
 extern crate rhododendron;
 extern crate substrate_bft as bft;
 extern crate substrate_codec as codec;
-extern crate substrate_keyring as keyring;
 extern crate substrate_primitives as primitives;
 extern crate substrate_runtime_support as runtime_support;
 extern crate substrate_runtime_primitives as runtime_primitives;
 #[macro_use] extern crate substrate_executor as executor;
 
-pub extern crate substrate_test_runtime as runtime;
 pub extern crate substrate_client as client;
+pub extern crate substrate_keyring as keyring;
+pub extern crate substrate_test_runtime as runtime;
 
 mod client_ext;
+mod block_builder_ext;
 
 pub use client_ext::TestClient;
+pub use block_builder_ext::BlockBuilderExt;
 
 mod local_executor {
 	#![allow(missing_docs)]