Light client RPCs (#7603)

* Implement registrar.

* Implement eth_getCode

* Don't wait for providers.

* Don't wait for providers.

* Fix linting and wasm tests.

js-old/src/redux/store.js

@@ -65,15 +65,15 @@ export default function (api, browserHistory, forEmbed = false) {
       .then(() => console.log('v1: started Status Provider'))
 
       .then(() => console.log('v1: starting Personal Provider...'))
-      .then(() => PersonalProvider.start())
+      .then(() => withTimeoutForLight('personal', PersonalProvider.start(), store))
       .then(() => console.log('v1: started Personal Provider'))
 
       .then(() => console.log('v1: starting Balances Provider...'))
-      .then(() => BalancesProvider.start())
+      .then(() => withTimeoutForLight('balances', BalancesProvider.start(), store))
       .then(() => console.log('v1: started Balances Provider'))
 
       .then(() => console.log('v1: starting Tokens Provider...'))
-      .then(() => TokensProvider.start())
+      .then(() => withTimeoutForLight('tokens', TokensProvider.start(), store))
       .then(() => console.log('v1: started Tokens Provider'));
   };
 
@@ -97,3 +97,39 @@ export default function (api, browserHistory, forEmbed = false) {
 
   return store;
 }
+
+function withTimeoutForLight (id, promise, store) {
+  const { nodeKind } = store.getState().nodeStatus;
+  const isLightNode = nodeKind.capability !== 'full';
+
+  if (!isLightNode) {
+    // make sure that no values are passed
+    return promise.then(() => {});
+  }
+
+  return new Promise((resolve, reject) => {
+    let isResolved = false;
+    const doResolve = () => {
+      if (!isResolved) {
+        isResolved = true;
+        resolve();
+      }
+    };
+    const timeout = setTimeout(() => {
+      console.warn(`Resolving ${id} by timeout.`);
+      doResolve();
+    }, 1000);
+
+    promise
+      .then(() => {
+        clearTimeout(timeout);
+        doResolve();
+      })
+      .catch(err => {
+        clearTimeout(timeout);
+        if (!isResolved) {
+          reject(err);
+        }
+      });
+  });
+}

rpc/src/v1/helpers/light_fetch.rs

@@ -146,19 +146,30 @@ impl LightFetch {
 			Err(e) => return Box::new(future::err(e)),
 		};
 
-		let maybe_future = self.sync.with_context(move |ctx| {
-			Box::new(self.on_demand.request_raw(ctx, reqs)
-				.expect("all back-references known to be valid; qed")
-				.map(|res| extract_header(&res, header_ref)
-					.expect("these responses correspond to requests that header_ref belongs to. \
-							 therefore it will not fail; qed"))
-				.map_err(errors::on_demand_cancel))
-		});
 
-		match maybe_future {
+		self.send_requests(reqs, |res|
-			Some(recv) => recv,
+			extract_header(&res, header_ref)
-			None => Box::new(future::err(errors::network_disabled()))
+				.expect("these responses correspond to requests that header_ref belongs to \
+						therefore it will not fail; qed")
+		)
 	}
+
+	/// Helper for getting contract code at a given block.
+	pub fn code(&self, address: Address, id: BlockId) -> BoxFuture<Vec<u8>> {
+		let mut reqs = Vec::new();
+		let header_ref = match self.make_header_requests(id, &mut reqs) {
+			Ok(r) => r,
+			Err(e) => return Box::new(future::err(e)),
+		};
+
+		reqs.push(request::Account { header: header_ref.clone(), address: address }.into());
+		let account_idx = reqs.len() - 1;
+		reqs.push(request::Code { header: header_ref, code_hash: Field::back_ref(account_idx, 0) }.into());
+
+		self.send_requests(reqs, |mut res| match res.pop() {
+			Some(OnDemandResponse::Code(code)) => code,
+			_ => panic!("responses correspond directly with requests in amount and type; qed"),
+		})
 	}
 
 	/// Helper for getting account info at a given block.
@@ -172,20 +183,10 @@ impl LightFetch {
 
 		reqs.push(request::Account { header: header_ref, address: address }.into());
 
-		let maybe_future = self.sync.with_context(move |ctx| {
+		self.send_requests(reqs, |mut res|match res.pop() {
-			Box::new(self.on_demand.request_raw(ctx, reqs)
-				.expect("all back-references known to be valid; qed")
-				.map(|mut res| match res.pop() {
 			Some(OnDemandResponse::Account(acc)) => acc,
 			_ => panic!("responses correspond directly with requests in amount and type; qed"),
 		})
-				.map_err(errors::on_demand_cancel))
-		});
-
-		match maybe_future {
-			Some(recv) => recv,
-			None => Box::new(future::err(errors::network_disabled()))
-		}
 	}
 
 	/// Helper for getting proved execution.
@@ -276,20 +277,10 @@ impl LightFetch {
 
 		reqs.push(request::Body(header_ref).into());
 
-		let maybe_future = self.sync.with_context(move |ctx| {
+		self.send_requests(reqs, |mut res| match res.pop() {
-			Box::new(self.on_demand.request_raw(ctx, reqs)
-				.expect(NO_INVALID_BACK_REFS)
-				.map(|mut res| match res.pop() {
 			Some(OnDemandResponse::Body(b)) => b,
 			_ => panic!("responses correspond directly with requests in amount and type; qed"),
 		})
-				.map_err(errors::on_demand_cancel))
-		});
-
-		match maybe_future {
-			Some(recv) => recv,
-			None => Box::new(future::err(errors::network_disabled()))
-		}
 	}
 
 	/// Get the block receipts. Fails on unknown block ID.
@@ -302,20 +293,10 @@ impl LightFetch {
 
 		reqs.push(request::BlockReceipts(header_ref).into());
 
-		let maybe_future = self.sync.with_context(move |ctx| {
+		self.send_requests(reqs, |mut res| match res.pop() {
-			Box::new(self.on_demand.request_raw(ctx, reqs)
-				.expect(NO_INVALID_BACK_REFS)
-				.map(|mut res| match res.pop() {
 			Some(OnDemandResponse::Receipts(b)) => b,
 			_ => panic!("responses correspond directly with requests in amount and type; qed"),
 		})
-				.map_err(errors::on_demand_cancel))
-		});
-
-		match maybe_future {
-			Some(recv) => recv,
-			None => Box::new(future::err(errors::network_disabled()))
-		}
 	}
 
 	/// Get transaction logs
@@ -432,6 +413,23 @@ impl LightFetch {
 			Either::B(extract_transaction)
 		}))
 	}
+
+	fn send_requests<T, F>(&self, reqs: Vec<OnDemandRequest>, parse_response: F) -> BoxFuture<T> where
+		F: FnOnce(Vec<OnDemandResponse>) -> T + Send + 'static,
+		T: Send + 'static,
+	{
+		let maybe_future = self.sync.with_context(move |ctx| {
+			Box::new(self.on_demand.request_raw(ctx, reqs)
+					 .expect(NO_INVALID_BACK_REFS)
+					 .map(parse_response)
+					 .map_err(errors::on_demand_cancel))
+		});
+
+		match maybe_future {
+			Some(recv) => recv,
+			None => Box::new(future::err(errors::network_disabled()))
+		}
+	}
 }
 
 #[derive(Clone)]

rpc/src/v1/impls/light/eth.rs

@@ -349,8 +349,8 @@ impl<T: LightChainClient + 'static> Eth for EthClient<T> {
 		}))
 	}
 
-	fn code_at(&self, _address: RpcH160, _num: Trailing<BlockNumber>) -> BoxFuture<Bytes> {
+	fn code_at(&self, address: RpcH160, num: Trailing<BlockNumber>) -> BoxFuture<Bytes> {
-		Box::new(future::err(errors::unimplemented(None)))
+		Box::new(self.fetcher().code(address.into(), num.unwrap_or_default().into()).map(Into::into))
 	}
 
 	fn send_raw_transaction(&self, raw: Bytes) -> Result<RpcH256> {

rpc/src/v1/impls/light/parity.rs

@@ -208,7 +208,12 @@ impl Parity for ParityClient {
 	}
 
 	fn registry_address(&self) -> Result<Option<H160>> {
-		Err(errors::light_unimplemented(None))
+		let reg = self.light_dispatch.client.engine().params().registrar;
+		if reg == Default::default() {
+			Ok(None)
+		} else {
+			Ok(Some(reg.into()))
+		}
 	}
 
 	fn rpc_settings(&self) -> Result<RpcSettings> {