Use randomized subscription ids for PubSub (#5756)

* Use randomized subscription ids for PubSub

* Use H64 instead of H128.

* iflet instead of match.

* Adding 0x.
This commit is contained in:
Tomasz Drwięga 2017-06-13 17:36:39 +02:00 committed by Gav Wood
parent 6afe0b0612
commit 57479dac27
6 changed files with 98 additions and 41 deletions

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@ -16,45 +16,79 @@
//! A map of subscribers. //! A map of subscribers.
use std::ops; use std::{ops, str};
use std::collections::HashMap; use std::collections::HashMap;
use jsonrpc_macros::pubsub::{Subscriber, Sink, SubscriptionId}; use jsonrpc_macros::pubsub::{Subscriber, Sink, SubscriptionId};
use rand::{Rng, StdRng};
use v1::types::H64;
#[derive(Clone, Debug)]
#[derive(Debug, Clone, Hash, Eq, PartialEq)]
pub struct Id(H64);
impl str::FromStr for Id {
type Err = String;
fn from_str(s: &str) -> Result<Self, Self::Err> {
if s.starts_with("0x") {
Ok(Id(s[2..].parse().map_err(|e| format!("{}", e))?))
} else {
Err("The id must start with 0x".into())
}
}
}
impl Id {
pub fn as_string(&self) -> String {
format!("0x{:?}", self.0)
}
}
#[derive(Clone)]
pub struct Subscribers<T> { pub struct Subscribers<T> {
next_id: u64, rand: StdRng,
subscriptions: HashMap<u64, T>, subscriptions: HashMap<Id, T>,
} }
impl<T> Default for Subscribers<T> { impl<T> Default for Subscribers<T> {
fn default() -> Self { fn default() -> Self {
Subscribers { Subscribers {
next_id: 0, rand: StdRng::new().expect("Valid random source is required."),
subscriptions: HashMap::new(), subscriptions: HashMap::new(),
} }
} }
} }
impl<T> Subscribers<T> { impl<T> Subscribers<T> {
fn next_id(&mut self) -> u64 { /// Create a new Subscribers with given random source.
self.next_id += 1; #[cfg(test)]
self.next_id pub fn new_test() -> Self {
Subscribers {
rand: ::rand::SeedableRng::from_seed([0usize].as_ref()),
subscriptions: HashMap::new(),
}
}
fn next_id(&mut self) -> Id {
let mut data = H64::default();
self.rand.fill_bytes(&mut data.0);
Id(data)
} }
/// Insert new subscription and return assigned id. /// Insert new subscription and return assigned id.
pub fn insert(&mut self, val: T) -> SubscriptionId { pub fn insert(&mut self, val: T) -> SubscriptionId {
let id = self.next_id(); let id = self.next_id();
debug!(target: "pubsub", "Adding subscription id={}", id); debug!(target: "pubsub", "Adding subscription id={:?}", id);
let s = id.as_string();
self.subscriptions.insert(id, val); self.subscriptions.insert(id, val);
SubscriptionId::Number(id) SubscriptionId::String(s)
} }
/// Removes subscription with given id and returns it (if any). /// Removes subscription with given id and returns it (if any).
pub fn remove(&mut self, id: &SubscriptionId) -> Option<T> { pub fn remove(&mut self, id: &SubscriptionId) -> Option<T> {
trace!(target: "pubsub", "Removing subscription id={:?}", id); trace!(target: "pubsub", "Removing subscription id={:?}", id);
match *id { match *id {
SubscriptionId::Number(id) => { SubscriptionId::String(ref id) => match id.parse() {
self.subscriptions.remove(&id) Ok(id) => self.subscriptions.remove(&id),
Err(_) => None,
}, },
_ => None, _ => None,
} }
@ -65,20 +99,15 @@ impl <T> Subscribers<Sink<T>> {
/// Assigns id and adds a subscriber to the list. /// Assigns id and adds a subscriber to the list.
pub fn push(&mut self, sub: Subscriber<T>) { pub fn push(&mut self, sub: Subscriber<T>) {
let id = self.next_id(); let id = self.next_id();
match sub.assign_id(SubscriptionId::Number(id)) { if let Ok(sink) = sub.assign_id(SubscriptionId::String(id.as_string())) {
Ok(sink) => { debug!(target: "pubsub", "Adding subscription id={:?}", id);
debug!(target: "pubsub", "Adding subscription id={:?}", id); self.subscriptions.insert(id, sink);
self.subscriptions.insert(id, sink);
},
Err(_) => {
self.next_id -= 1;
},
} }
} }
} }
impl<T> ops::Deref for Subscribers<T> { impl<T> ops::Deref for Subscribers<T> {
type Target = HashMap<u64, T>; type Target = HashMap<Id, T>;
fn deref(&self) -> &Self::Target { fn deref(&self) -> &Self::Target {
&self.subscriptions &self.subscriptions

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@ -54,6 +54,14 @@ impl<S: core::Middleware<Metadata>> GenericPollManager<S> {
} }
} }
/// Creates new poll manager with deterministic ids.
#[cfg(test)]
pub fn new_test(rpc: MetaIoHandler<Metadata, S>) -> Self {
let mut manager = Self::new(rpc);
manager.subscribers = Subscribers::new_test();
manager
}
/// Subscribes to update from polling given method. /// Subscribes to update from polling given method.
pub fn subscribe(&mut self, metadata: Metadata, method: String, params: core::Params) pub fn subscribe(&mut self, metadata: Metadata, method: String, params: core::Params)
-> (SubscriptionId, mpsc::Receiver<Result<core::Value, core::Error>>) -> (SubscriptionId, mpsc::Receiver<Result<core::Value, core::Error>>)
@ -81,7 +89,7 @@ impl<S: core::Middleware<Metadata>> GenericPollManager<S> {
for (id, subscription) in self.subscribers.iter() { for (id, subscription) in self.subscribers.iter() {
let call = core::MethodCall { let call = core::MethodCall {
jsonrpc: Some(core::Version::V2), jsonrpc: Some(core::Version::V2),
id: core::Id::Num(*id as u64), id: core::Id::Str(id.as_string()),
method: subscription.method.clone(), method: subscription.method.clone(),
params: Some(subscription.params.clone()), params: Some(subscription.params.clone()),
}; };
@ -139,7 +147,7 @@ mod tests {
Ok(Value::String("world".into())) Ok(Value::String("world".into()))
} }
}); });
GenericPollManager::new(io) GenericPollManager::new_test(io)
} }
#[test] #[test]
@ -148,7 +156,7 @@ mod tests {
let mut el = reactor::Core::new().unwrap(); let mut el = reactor::Core::new().unwrap();
let mut poll_manager = poll_manager(); let mut poll_manager = poll_manager();
let (id, rx) = poll_manager.subscribe(Default::default(), "hello".into(), Params::None); let (id, rx) = poll_manager.subscribe(Default::default(), "hello".into(), Params::None);
assert_eq!(id, SubscriptionId::Number(1)); assert_eq!(id, SubscriptionId::String("0x416d77337e24399d".into()));
// then // then
poll_manager.tick().wait().unwrap(); poll_manager.tick().wait().unwrap();

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@ -48,14 +48,22 @@ impl<C> EthPubSubClient<C> {
let heads_subscribers = Arc::new(Mutex::new(Subscribers::default())); let heads_subscribers = Arc::new(Mutex::new(Subscribers::default()));
EthPubSubClient { EthPubSubClient {
handler: Arc::new(ChainNotificationHandler { handler: Arc::new(ChainNotificationHandler {
client: client, client,
remote: remote, remote,
heads_subscribers: heads_subscribers.clone(), heads_subscribers: heads_subscribers.clone(),
}), }),
heads_subscribers: heads_subscribers, heads_subscribers,
} }
} }
/// Creates new `EthPubSubCient` with deterministic subscription ids.
#[cfg(test)]
pub fn new_test(client: Arc<C>, remote: Remote) -> Self {
let client = Self::new(client, remote);
*client.heads_subscribers.lock() = Subscribers::new_test();
client
}
/// Returns a chain notification handler. /// Returns a chain notification handler.
pub fn handler(&self) -> Arc<ChainNotificationHandler<C>> { pub fn handler(&self) -> Arc<ChainNotificationHandler<C>> {
self.handler.clone() self.handler.clone()

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@ -55,12 +55,22 @@ impl<S: core::Middleware<Metadata>> PubSubClient<S> {
); );
PubSubClient { PubSubClient {
poll_manager: poll_manager, poll_manager,
remote: remote, remote,
} }
} }
} }
impl PubSubClient<core::NoopMiddleware> {
/// Creates new `PubSubClient` with deterministic ids.
#[cfg(test)]
pub fn new_test(rpc: MetaIoHandler<Metadata, core::NoopMiddleware>, remote: Remote) -> Self {
let client = Self::new(MetaIoHandler::with_middleware(Default::default()), remote);
*client.poll_manager.write() = GenericPollManager::new_test(rpc);
client
}
}
impl<S: core::Middleware<Metadata>> PubSub for PubSubClient<S> { impl<S: core::Middleware<Metadata>> PubSub for PubSubClient<S> {
type Metadata = Metadata; type Metadata = Metadata;

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@ -36,7 +36,7 @@ fn should_subscribe_to_new_heads() {
let h2 = client.block_hash_delta_minus(2); let h2 = client.block_hash_delta_minus(2);
let h1 = client.block_hash_delta_minus(3); let h1 = client.block_hash_delta_minus(3);
let pubsub = EthPubSubClient::new(Arc::new(client), el.remote()); let pubsub = EthPubSubClient::new_test(Arc::new(client), el.remote());
let handler = pubsub.handler(); let handler = pubsub.handler();
let pubsub = pubsub.to_delegate(); let pubsub = pubsub.to_delegate();
@ -49,13 +49,13 @@ fn should_subscribe_to_new_heads() {
// Subscribe // Subscribe
let request = r#"{"jsonrpc": "2.0", "method": "eth_subscribe", "params": ["newHeads"], "id": 1}"#; let request = r#"{"jsonrpc": "2.0", "method": "eth_subscribe", "params": ["newHeads"], "id": 1}"#;
let response = r#"{"jsonrpc":"2.0","result":1,"id":1}"#; let response = r#"{"jsonrpc":"2.0","result":"0x416d77337e24399d","id":1}"#;
assert_eq!(io.handle_request_sync(request, metadata.clone()), Some(response.to_owned())); assert_eq!(io.handle_request_sync(request, metadata.clone()), Some(response.to_owned()));
// Check notifications // Check notifications
handler.new_blocks(vec![], vec![], vec![h1], vec![], vec![], vec![], 0); handler.new_blocks(vec![], vec![], vec![h1], vec![], vec![], vec![], 0);
let (res, receiver) = receiver.into_future().wait().unwrap(); let (res, receiver) = receiver.into_future().wait().unwrap();
let response = r#"{"jsonrpc":"2.0","method":"eth_subscription","params":{"result":{"author":"0x0000000000000000000000000000000000000000","difficulty":"0x1","extraData":"0x","gasLimit":"0xf4240","gasUsed":"0x0","hash":"0x3457d2fa2e3dd33c78ac681cf542e429becf718859053448748383af67e23218","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","miner":"0x0000000000000000000000000000000000000000","number":"0x1","parentHash":"0x0cd786a2425d16f152c658316c423e6ce1181e15c3295826d7c9904cba9ce303","receiptsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","sealFields":[],"sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","size":"0x1c9","stateRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","timestamp":"0x0","transactionsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"},"subscription":1}}"#; let response = r#"{"jsonrpc":"2.0","method":"eth_subscription","params":{"result":{"author":"0x0000000000000000000000000000000000000000","difficulty":"0x1","extraData":"0x","gasLimit":"0xf4240","gasUsed":"0x0","hash":"0x3457d2fa2e3dd33c78ac681cf542e429becf718859053448748383af67e23218","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","miner":"0x0000000000000000000000000000000000000000","number":"0x1","parentHash":"0x0cd786a2425d16f152c658316c423e6ce1181e15c3295826d7c9904cba9ce303","receiptsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","sealFields":[],"sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","size":"0x1c9","stateRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","timestamp":"0x0","transactionsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"},"subscription":"0x416d77337e24399d"}}"#;
assert_eq!(res, Some(response.into())); assert_eq!(res, Some(response.into()));
// Notify about two blocks // Notify about two blocks
@ -63,14 +63,14 @@ fn should_subscribe_to_new_heads() {
// Receive both // Receive both
let (res, receiver) = receiver.into_future().wait().unwrap(); let (res, receiver) = receiver.into_future().wait().unwrap();
let response = r#"{"jsonrpc":"2.0","method":"eth_subscription","params":{"result":{"author":"0x0000000000000000000000000000000000000000","difficulty":"0x2","extraData":"0x","gasLimit":"0xf4240","gasUsed":"0x0","hash":"0x44e5ecf454ea99af9d8a8f2ca0daba96964c90de05db7a78f59b84ae9e749706","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","miner":"0x0000000000000000000000000000000000000000","number":"0x2","parentHash":"0x3457d2fa2e3dd33c78ac681cf542e429becf718859053448748383af67e23218","receiptsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","sealFields":[],"sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","size":"0x1c9","stateRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","timestamp":"0x0","transactionsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"},"subscription":1}}"#; let response = r#"{"jsonrpc":"2.0","method":"eth_subscription","params":{"result":{"author":"0x0000000000000000000000000000000000000000","difficulty":"0x2","extraData":"0x","gasLimit":"0xf4240","gasUsed":"0x0","hash":"0x44e5ecf454ea99af9d8a8f2ca0daba96964c90de05db7a78f59b84ae9e749706","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","miner":"0x0000000000000000000000000000000000000000","number":"0x2","parentHash":"0x3457d2fa2e3dd33c78ac681cf542e429becf718859053448748383af67e23218","receiptsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","sealFields":[],"sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","size":"0x1c9","stateRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","timestamp":"0x0","transactionsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"},"subscription":"0x416d77337e24399d"}}"#;
assert_eq!(res, Some(response.into())); assert_eq!(res, Some(response.into()));
let (res, receiver) = receiver.into_future().wait().unwrap(); let (res, receiver) = receiver.into_future().wait().unwrap();
let response = r#"{"jsonrpc":"2.0","method":"eth_subscription","params":{"result":{"author":"0x0000000000000000000000000000000000000000","difficulty":"0x3","extraData":"0x","gasLimit":"0xf4240","gasUsed":"0x0","hash":"0xdf04a98bb0c6fa8441bd429822f65a46d0cb553f6bcef602b973e65c81497f8e","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","miner":"0x0000000000000000000000000000000000000000","number":"0x3","parentHash":"0x44e5ecf454ea99af9d8a8f2ca0daba96964c90de05db7a78f59b84ae9e749706","receiptsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","sealFields":[],"sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","size":"0x1c9","stateRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","timestamp":"0x0","transactionsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"},"subscription":1}}"#; let response = r#"{"jsonrpc":"2.0","method":"eth_subscription","params":{"result":{"author":"0x0000000000000000000000000000000000000000","difficulty":"0x3","extraData":"0x","gasLimit":"0xf4240","gasUsed":"0x0","hash":"0xdf04a98bb0c6fa8441bd429822f65a46d0cb553f6bcef602b973e65c81497f8e","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","miner":"0x0000000000000000000000000000000000000000","number":"0x3","parentHash":"0x44e5ecf454ea99af9d8a8f2ca0daba96964c90de05db7a78f59b84ae9e749706","receiptsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","sealFields":[],"sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","size":"0x1c9","stateRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","timestamp":"0x0","transactionsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"},"subscription":"0x416d77337e24399d"}}"#;
assert_eq!(res, Some(response.into())); assert_eq!(res, Some(response.into()));
// And unsubscribe // And unsubscribe
let request = r#"{"jsonrpc": "2.0", "method": "eth_unsubscribe", "params": [1], "id": 1}"#; let request = r#"{"jsonrpc": "2.0", "method": "eth_unsubscribe", "params": ["0x416d77337e24399d"], "id": 1}"#;
let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#; let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;
assert_eq!(io.handle_request_sync(request, metadata), Some(response.to_owned())); assert_eq!(io.handle_request_sync(request, metadata), Some(response.to_owned()));
@ -83,7 +83,7 @@ fn should_return_unimplemented() {
// given // given
let el = EventLoop::spawn(); let el = EventLoop::spawn();
let client = TestBlockChainClient::new(); let client = TestBlockChainClient::new();
let pubsub = EthPubSubClient::new(Arc::new(client), el.remote()); let pubsub = EthPubSubClient::new_test(Arc::new(client), el.remote());
let pubsub = pubsub.to_delegate(); let pubsub = pubsub.to_delegate();
let mut io = MetaIoHandler::default(); let mut io = MetaIoHandler::default();

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@ -42,7 +42,7 @@ fn should_subscribe_to_a_method() {
// given // given
let el = EventLoop::spawn(); let el = EventLoop::spawn();
let rpc = rpc(); let rpc = rpc();
let pubsub = PubSubClient::new(rpc, el.remote()).to_delegate(); let pubsub = PubSubClient::new_test(rpc, el.remote()).to_delegate();
let mut io = MetaIoHandler::default(); let mut io = MetaIoHandler::default();
io.extend_with(pubsub); io.extend_with(pubsub);
@ -53,20 +53,22 @@ fn should_subscribe_to_a_method() {
// Subscribe // Subscribe
let request = r#"{"jsonrpc": "2.0", "method": "parity_subscribe", "params": ["hello", []], "id": 1}"#; let request = r#"{"jsonrpc": "2.0", "method": "parity_subscribe", "params": ["hello", []], "id": 1}"#;
let response = r#"{"jsonrpc":"2.0","result":1,"id":1}"#; let response = r#"{"jsonrpc":"2.0","result":"0x416d77337e24399d","id":1}"#;
assert_eq!(io.handle_request_sync(request, metadata.clone()), Some(response.to_owned())); assert_eq!(io.handle_request_sync(request, metadata.clone()), Some(response.to_owned()));
// Check notifications // Check notifications
let (res, receiver) = receiver.into_future().wait().unwrap(); let (res, receiver) = receiver.into_future().wait().unwrap();
let response = r#"{"jsonrpc":"2.0","method":"parity_subscription","params":{"result":"hello","subscription":1}}"#; let response =
r#"{"jsonrpc":"2.0","method":"parity_subscription","params":{"result":"hello","subscription":"0x416d77337e24399d"}}"#;
assert_eq!(res, Some(response.into())); assert_eq!(res, Some(response.into()));
let (res, receiver) = receiver.into_future().wait().unwrap(); let (res, receiver) = receiver.into_future().wait().unwrap();
let response = r#"{"jsonrpc":"2.0","method":"parity_subscription","params":{"result":"world","subscription":1}}"#; let response =
r#"{"jsonrpc":"2.0","method":"parity_subscription","params":{"result":"world","subscription":"0x416d77337e24399d"}}"#;
assert_eq!(res, Some(response.into())); assert_eq!(res, Some(response.into()));
// And unsubscribe // And unsubscribe
let request = r#"{"jsonrpc": "2.0", "method": "parity_unsubscribe", "params": [1], "id": 1}"#; let request = r#"{"jsonrpc": "2.0", "method": "parity_unsubscribe", "params": ["0x416d77337e24399d"], "id": 1}"#;
let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#; let response = r#"{"jsonrpc":"2.0","result":true,"id":1}"#;
assert_eq!(io.handle_request_sync(request, metadata), Some(response.to_owned())); assert_eq!(io.handle_request_sync(request, metadata), Some(response.to_owned()));