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// Copyright 2019-2021 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any
// person obtaining a copy of this software and associated
// documentation files (the "Software"), to deal in the
// Software without restriction, including without
// limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice
// shall be included in all copies or substantial portions
// of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
// SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
// IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
use std::collections::hash_map::Entry;
use std::fmt::{self, Debug};
use std::future::Future;
use std::ops::{Deref, DerefMut};
use std::sync::Arc;
use crate::error::{Error, SubscriptionClosed, SubscriptionClosedReason};
use crate::id_providers::RandomIntegerIdProvider;
use crate::server::resource_limiting::{ResourceGuard, ResourceTable, ResourceVec, Resources};
use crate::traits::{IdProvider, ToRpcParams};
use futures_channel::{mpsc, oneshot};
use futures_util::future::Either;
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use futures_util::{future::BoxFuture, FutureExt, Stream, StreamExt, TryStream, TryStreamExt};
use jsonrpsee_types::error::{ErrorCode, CALL_EXECUTION_FAILED_CODE};
ErrorResponse, Id, Params, Request, Response, SubscriptionId as RpcSubscriptionId, SubscriptionPayload,
SubscriptionResponse,
use parking_lot::Mutex;
use rustc_hash::FxHashMap;
/// A `MethodCallback` is an RPC endpoint, callable with a standard JSON-RPC request,
/// implemented as a function pointer to a `Fn` function taking four arguments:
/// the `id`, `params`, a channel the function uses to communicate the result (or error)
/// back to `jsonrpsee`, and the connection ID (useful for the websocket transport).
pub type SyncMethod = Arc<dyn Send + Sync + Fn(Id, Params, &MethodSink) -> bool>;
/// Similar to [`SyncMethod`], but represents an asynchronous handler and takes an additional argument containing a [`ResourceGuard`] if configured.
pub type AsyncMethod<'a> = Arc<
dyn Send + Sync + Fn(Id<'a>, Params<'a>, MethodSink, ConnectionId, Option<ResourceGuard>) -> BoxFuture<'a, bool>,
/// Method callback for subscriptions.
pub type SubscriptionMethod = Arc<dyn Send + Sync + Fn(Id, Params, &MethodSink, ConnState) -> bool>;
/// Connection ID, used for stateful protocol such as WebSockets.
/// For stateless protocols such as http it's unused, so feel free to set it some hardcoded value.
pub type ConnectionId = usize;
/// Raw response from an RPC
/// A 3-tuple containing:
/// - Call result as a `String`,
/// - a [`mpsc::UnboundedReceiver<String>`] to receive future subscription results
/// - a [`tokio::sync::Notify`] to allow subscribers to notify their [`SubscriptionSink`] when they disconnect.
pub type RawRpcResponse = (String, mpsc::UnboundedReceiver<String>, Arc<Notify>);
/// Helper struct to manage subscriptions.
pub struct ConnState<'a> {
/// Connection ID
pub conn_id: ConnectionId,
/// Get notified when the connection to subscribers is closed.
pub close_notify: Arc<Notify>,
/// ID provider.
pub id_provider: &'a dyn IdProvider,
}
impl<'a> std::fmt::Debug for ConnState<'a> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("ConnState").field("conn_id", &self.conn_id).field("close", &self.close_notify).finish()
type Subscribers = Arc<Mutex<FxHashMap<SubscriptionKey, (MethodSink, oneshot::Receiver<()>)>>>;
/// Represent a unique subscription entry based on [`RpcSubscriptionId`] and [`ConnectionId`].
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct SubscriptionKey {
conn_id: ConnectionId,
sub_id: RpcSubscriptionId<'static>,
/// Callback wrapper that can be either sync or async.
pub enum MethodKind {
/// Asynchronous method handler.
/// Subscription method handler
Subscription(SubscriptionMethod),
/// Information about resources the method uses during its execution. Initialized when the the server starts.
#[derive(Clone, Debug)]
enum MethodResources {
/// Uninitialized resource table, mapping string label to units.
Uninitialized(Box<[(&'static str, u16)]>),
/// Initialized resource table containing units for each `ResourceId`.
Initialized(ResourceTable),
}
/// Method callback wrapper that contains a sync or async closure,
/// plus a table with resources it needs to claim to run
#[derive(Clone, Debug)]
pub struct MethodCallback {
callback: MethodKind,
resources: MethodResources,
}
/// Result of a method, either direct value or a future of one.
pub enum MethodResult<T> {
/// Result by value
Sync(T),
/// Future of a value
Async(BoxFuture<'static, T>),
}
impl<T: Debug> Debug for MethodResult<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
MethodResult::Sync(result) => result.fmt(f),
MethodResult::Async(_) => f.write_str("<future>"),
}
}
}
/// Builder for configuring resources used by a method.
#[derive(Debug)]
pub struct MethodResourcesBuilder<'a> {
build: ResourceVec<(&'static str, u16)>,
callback: &'a mut MethodCallback,
}
impl<'a> MethodResourcesBuilder<'a> {
/// Define how many units of a given named resource the method uses during its execution.
pub fn resource(mut self, label: &'static str, units: u16) -> Result<Self, Error> {
self.build.try_push((label, units)).map_err(|_| Error::MaxResourcesReached)?;
Ok(self)
}
}
impl<'a> Drop for MethodResourcesBuilder<'a> {
fn drop(&mut self) {
self.callback.resources = MethodResources::Uninitialized(self.build[..].into());
}
}
fn new_sync(callback: SyncMethod) -> Self {
MethodCallback { callback: MethodKind::Sync(callback), resources: MethodResources::Uninitialized([].into()) }
}
fn new_async(callback: AsyncMethod<'static>) -> Self {
MethodCallback { callback: MethodKind::Async(callback), resources: MethodResources::Uninitialized([].into()) }
}
fn new_subscription(callback: SubscriptionMethod) -> Self {
MethodCallback {
callback: MethodKind::Subscription(callback),
resources: MethodResources::Uninitialized([].into()),
}
}
/// Attempt to claim resources prior to executing a method. On success returns a guard that releases
/// claimed resources when dropped.
pub fn claim(&self, name: &str, resources: &Resources) -> Result<ResourceGuard, Error> {
match self.resources {
MethodResources::Uninitialized(_) => Err(Error::UninitializedMethod(name.into())),
MethodResources::Initialized(units) => resources.claim(units),
}
}
/// Get handle to the callback.
pub fn inner(&self) -> &MethodKind {
&self.callback
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
Self::Async(_) => write!(f, "Async"),
Self::Sync(_) => write!(f, "Sync"),
Self::Subscription(_) => write!(f, "Subscription"),
/// Reference-counted, clone-on-write collection of synchronous and asynchronous methods.
#[derive(Default, Debug, Clone)]
callbacks: Arc<FxHashMap<&'static str, MethodCallback>>,
impl Methods {
/// Creates a new empty [`Methods`].
pub fn new() -> Self {
Self::default()
fn verify_method_name(&mut self, name: &'static str) -> Result<(), Error> {
if self.callbacks.contains_key(name) {
return Err(Error::MethodAlreadyRegistered(name.into()));
}
Ok(())
}
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/// Inserts the method callback for a given name, or returns an error if the name was already taken.
/// On success it returns a mut reference to the [`MethodCallback`] just inserted.
fn verify_and_insert(
&mut self,
name: &'static str,
callback: MethodCallback,
) -> Result<&mut MethodCallback, Error> {
match self.mut_callbacks().entry(name) {
Entry::Occupied(_) => Err(Error::MethodAlreadyRegistered(name.into())),
Entry::Vacant(vacant) => Ok(vacant.insert(callback)),
}
}
/// Initialize resources for all methods in this collection. This method has no effect if called more than once.
pub fn initialize_resources(mut self, resources: &Resources) -> Result<Self, Error> {
let callbacks = self.mut_callbacks();
for (&method_name, callback) in callbacks.iter_mut() {
if let MethodResources::Uninitialized(uninit) = &callback.resources {
let mut map = resources.defaults;
for &(label, units) in uninit.iter() {
let idx = match resources.labels.iter().position(|&l| l == label) {
Some(idx) => idx,
None => return Err(Error::ResourceNameNotFoundForMethod(label, method_name)),
};
// If resource capacity set to `0`, we ignore the unit value of the method
// and set it to `0` as well, effectively making the resource unlimited.
if resources.capacities[idx] == 0 {
map[idx] = 0;
} else {
map[idx] = units;
}
}
callback.resources = MethodResources::Initialized(map);
}
}
Ok(self)
}
/// Helper for obtaining a mut ref to the callbacks HashMap.
fn mut_callbacks(&mut self) -> &mut FxHashMap<&'static str, MethodCallback> {
Arc::make_mut(&mut self.callbacks)
}
/// Merge two [`Methods`]'s by adding all [`MethodCallback`]s from `other` into `self`.
/// Fails if any of the methods in `other` is present already.
pub fn merge(&mut self, other: impl Into<Methods>) -> Result<(), Error> {
let mut other = other.into();
self.verify_method_name(name)?;
}
let callbacks = self.mut_callbacks();
for (name, callback) in other.mut_callbacks().drain() {
callbacks.insert(name, callback);
/// Returns the method callback.
pub fn method(&self, method_name: &str) -> Option<&MethodCallback> {
self.callbacks.get(method_name)
/// Returns the method callback along with its name. The returned name is same as the
/// `method_name`, but its lifetime bound is `'static`.
pub fn method_with_name(&self, method_name: &str) -> Option<(&'static str, &MethodCallback)> {
self.callbacks.get_key_value(method_name).map(|(k, v)| (*k, v))
}
/// Helper to call a method on the `RPC module` without having to spin up a server.
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///
/// The params must be serializable as JSON array, see [`ToRpcParams`] for further documentation.
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///
/// Returns the decoded value of the `result field` in JSON-RPC response if succesful.
///
/// # Examples
///
/// ```
/// #[tokio::main]
/// async fn main() {
/// use jsonrpsee::RpcModule;
///
/// let mut module = RpcModule::new(());
/// module.register_method("echo_call", |params, _| {
/// params.one::<u64>().map_err(Into::into)
/// }).unwrap();
///
/// let echo: u64 = module.call("echo_call", [1_u64]).await.unwrap();
/// assert_eq!(echo, 1);
/// }
/// ```
pub async fn call<Params: ToRpcParams, T: DeserializeOwned>(
&self,
method: &str,
params: Params,
) -> Result<T, Error> {
let params = params.to_rpc_params()?;
let req = Request::new(method.into(), Some(¶ms), Id::Number(0));
tracing::trace!("[Methods::call] Calling method: {:?}, params: {:?}", method, params);
let (resp, _, _) = self.inner_call(req).await;
if let Ok(res) = serde_json::from_str::<Response<T>>(&resp) {
return Ok(res.result);
if let Ok(err) = serde_json::from_str::<ErrorResponse>(&resp) {
return Err(Error::Call(err.error.to_call_error()));
}
unreachable!("Invalid JSON-RPC response is not possible using jsonrpsee; this is bug please file an issue");
/// Make a request (JSON-RPC method call or subscription) by using raw JSON.
/// Returns the raw JSON response to the call and a stream to receive notifications if the call was a subscription.
/// # Examples
///
/// ```
/// #[tokio::main]
/// async fn main() {
/// use jsonrpsee::RpcModule;
/// use jsonrpsee::types::Response;
/// use futures_util::StreamExt;
///
/// let mut module = RpcModule::new(());
/// module.register_subscription("hi", "hi", "goodbye", |_, mut sink, _| {
/// sink.send(&"one answer").unwrap();
/// Ok(())
/// }).unwrap();
/// let (resp, mut stream) = module.raw_json_request(r#"{"jsonrpc":"2.0","method":"hi","id":0}"#).await.unwrap();
/// let resp = serde_json::from_str::<Response<u64>>(&resp).unwrap();
/// let sub_resp = stream.next().await.unwrap();
/// assert_eq!(
/// format!(r#"{{"jsonrpc":"2.0","method":"hi","params":{{"subscription":{},"result":"one answer"}}}}"#, resp.result),
/// sub_resp
/// );
pub async fn raw_json_request(&self, call: &str) -> Result<(String, mpsc::UnboundedReceiver<String>), Error> {
tracing::trace!("[Methods::raw_json_request] {:?}", call);
let req: Request = serde_json::from_str(call)?;
let (resp, rx, _) = self.inner_call(req).await;
Ok((resp, rx))
/// Execute a callback.
async fn inner_call(&self, req: Request<'_>) -> RawRpcResponse {
let (tx_sink, mut rx_sink) = mpsc::unbounded();
let sink = MethodSink::new(tx_sink);
let id = req.id.clone();
let params = Params::new(req.params.map(|params| params.get()));
let _result = match self.method(&req.method).map(|c| &c.callback) {
None => sink.send_error(req.id, ErrorCode::MethodNotFound.into()),
Some(MethodKind::Sync(cb)) => (cb)(id, params, &sink),
Some(MethodKind::Async(cb)) => (cb)(id.into_owned(), params.into_owned(), sink, 0, None).await,
Some(MethodKind::Subscription(cb)) => {
let close_notify = notify.clone();
let conn_state = ConnState { conn_id: 0, close_notify, id_provider: &RandomIntegerIdProvider };
(cb)(id, params, &sink, conn_state)
}
};
let resp = rx_sink.next().await.expect("tx and rx still alive; qed");
(resp, rx_sink, notify)
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}
/// Helper to create a subscription on the `RPC module` without having to spin up a server.
///
/// The params must be serializable as JSON array, see [`ToRpcParams`] for further documentation.
///
/// Returns [`Subscription`] on succes which can used to get results from the subscriptions.
///
/// # Examples
///
/// ```
/// #[tokio::main]
/// async fn main() {
/// use jsonrpsee::{RpcModule, types::EmptyParams};
///
/// let mut module = RpcModule::new(());
/// module.register_subscription("hi", "hi", "goodbye", |_, mut sink, _| {
/// sink.send(&"one answer").unwrap();
/// Ok(())
/// }).unwrap();
///
/// let mut sub = module.subscribe("hi", EmptyParams::new()).await.unwrap();
/// // In this case we ignore the subscription ID,
/// let (sub_resp, _sub_id) = sub.next::<String>().await.unwrap().unwrap();
/// assert_eq!(&sub_resp, "one answer");
/// }
/// ```
pub async fn subscribe(&self, sub_method: &str, params: impl ToRpcParams) -> Result<Subscription, Error> {
let params = params.to_rpc_params()?;
let req = Request::new(sub_method.into(), Some(¶ms), Id::Number(0));
tracing::trace!("[Methods::subscribe] Calling subscription method: {:?}, params: {:?}", sub_method, params);
let (response, rx, close_notify) = self.inner_call(req).await;
let subscription_response = serde_json::from_str::<Response<RpcSubscriptionId>>(&response)?;
let sub_id = subscription_response.result.into_owned();
let close_notify = Some(close_notify);
Ok(Subscription { sub_id, rx, close_notify })
/// Returns an `Iterator` with all the method names registered on this server.
pub fn method_names(&self) -> impl Iterator<Item = &'static str> + '_ {
self.callbacks.keys().copied()
}
}
impl<Context> Deref for RpcModule<Context> {
type Target = Methods;
fn deref(&self) -> &Methods {
&self.methods
}
}
impl<Context> DerefMut for RpcModule<Context> {
fn deref_mut(&mut self) -> &mut Methods {
&mut self.methods
}
}
/// Sets of JSON-RPC methods can be organized into a "module"s that are in turn registered on the server or,
/// alternatively, merged with other modules to construct a cohesive API. [`RpcModule`] wraps an additional context
/// argument that can be used to access data during call execution.
pub struct RpcModule<Context> {
ctx: Arc<Context>,
impl<Context> RpcModule<Context> {
/// Create a new module with a given shared `Context`.
pub fn new(ctx: Context) -> Self {
Self { ctx: Arc::new(ctx), methods: Default::default() }
/// Transform a module into an `RpcModule<()>` (unit context).
pub fn remove_context(self) -> RpcModule<()> {
let mut module = RpcModule::new(());
module.methods = self.methods;
module
}
impl<Context> From<RpcModule<Context>> for Methods {
fn from(module: RpcModule<Context>) -> Methods {
module.methods
}
}
impl<Context: Send + Sync + 'static> RpcModule<Context> {
/// Register a new synchronous RPC method, which computes the response with the given callback.
pub fn register_method<R, F>(
&mut self,
method_name: &'static str,
callback: F,
) -> Result<MethodResourcesBuilder, Error>
F: Fn(Params, &Context) -> Result<R, Error> + Send + Sync + 'static,
MethodCallback::new_sync(Arc::new(move |id, params, sink| match callback(params, &*ctx) {
Ok(res) => sink.send_response(id, res),
Err(err) => sink.send_call_error(id, err),
Ok(MethodResourcesBuilder { build: ResourceVec::new(), callback })
/// Register a new asynchronous RPC method, which computes the response with the given callback.
pub fn register_async_method<R, Fun, Fut>(
&mut self,
method_name: &'static str,
callback: Fun,
) -> Result<MethodResourcesBuilder, Error>
where
R: Serialize + Send + Sync + 'static,
Fut: Future<Output = Result<R, Error>> + Send,
Fun: (Fn(Params<'static>, Arc<Context>) -> Fut) + Copy + Send + Sync + 'static,
{
let ctx = self.ctx.clone();
MethodCallback::new_async(Arc::new(move |id, params, sink, _, claimed| {
let ctx = ctx.clone();
let future = async move {
let result = match callback(params, ctx).await {
Ok(res) => sink.send_response(id, res),
Err(err) => sink.send_call_error(id, err),
// Release claimed resources
drop(claimed);
Ok(MethodResourcesBuilder { build: ResourceVec::new(), callback })
/// Register a new **blocking** synchronous RPC method, which computes the response with the given callback.
/// Unlike the regular [`register_method`](RpcModule::register_method), this method can block its thread and perform expensive computations.
pub fn register_blocking_method<R, F>(
&mut self,
method_name: &'static str,
callback: F,
) -> Result<MethodResourcesBuilder, Error>
where
Context: Send + Sync + 'static,
R: Serialize,
F: Fn(Params, Arc<Context>) -> Result<R, Error> + Copy + Send + Sync + 'static,
{
let ctx = self.ctx.clone();
let callback = self.methods.verify_and_insert(
method_name,
MethodCallback::new_async(Arc::new(move |id, params, sink, _, claimed| {
let ctx = ctx.clone();
tokio::task::spawn_blocking(move || {
let result = match callback(params, ctx) {
Ok(res) => sink.send_response(id, res),
Err(err) => sink.send_call_error(id, err),
};
// Release claimed resources
drop(claimed);
.map(|result| match result {
Ok(r) => r,
Err(err) => {
tracing::error!("Join error for blocking RPC method: {:?}", err);
false
}
})
.boxed()
})),
)?;
Ok(MethodResourcesBuilder { build: ResourceVec::new(), callback })
}
/// Register a new publish/subscribe interface using JSON-RPC notifications.
///
/// It implements the [ethereum pubsub specification](https://geth.ethereum.org/docs/rpc/pubsub)
/// with an option to choose custom subscription ID generation.
///
/// Furthermore, it generates the `unsubscribe implementation` where a `bool` is used as
/// the result to indicate whether the subscription was successfully unsubscribed to or not.
/// For instance an `unsubscribe call` may fail if a non-existent subscriptionID is used in the call.
///
/// This method ensures that the `subscription_method_name` and `unsubscription_method_name` are unique.
/// The `notif_method_name` argument sets the content of the `method` field in the JSON document that
/// the server sends back to the client. The uniqueness of this value is not machine checked and it's up to
/// the user to ensure it is not used in any other [`RpcModule`] used in the server.
///
/// # Arguments
///
/// * `subscription_method_name` - name of the method to call to initiate a subscription
/// * `notif_method_name` - name of method to be used in the subscription payload (technically a JSON-RPC notification)
/// * `unsubscription_method` - name of the method to call to terminate a subscription
/// * `callback` - A callback to invoke on each subscription; it takes three parameters:
/// - [`Params`]: JSON-RPC parameters in the subscription call.
/// - [`SubscriptionSink`]: A sink to send messages to the subscriber.
/// - Context: Any type that can be embedded into the [`RpcModule`].
///
/// # Examples
///
/// ```no_run
///
/// use jsonrpsee_core::server::rpc_module::RpcModule;
/// ctx.register_subscription("sub", "notif_name", "unsub", |params, mut sink, ctx| {
/// std::thread::spawn(move || {
/// });
/// Ok(())
/// });
/// ```
pub fn register_subscription<F>(
&mut self,
subscribe_method_name: &'static str,
notif_method_name: &'static str,
unsubscribe_method_name: &'static str,
callback: F,
) -> Result<(), Error>
where
F: Fn(Params, SubscriptionSink, Arc<Context>) -> Result<(), Error> + Send + Sync + 'static,
if subscribe_method_name == unsubscribe_method_name {
return Err(Error::SubscriptionNameConflict(subscribe_method_name.into()));
}
self.methods.verify_method_name(subscribe_method_name)?;
self.methods.verify_method_name(unsubscribe_method_name)?;
let subscribers = Subscribers::default();
let subscribers = subscribers.clone();
self.methods.mut_callbacks().insert(
MethodCallback::new_subscription(Arc::new(move |id, params, method_sink, conn| {
let (conn_tx, conn_rx) = oneshot::channel::<()>();
let sub_id: RpcSubscriptionId = conn.id_provider.next_id().into_owned();
let uniq_sub = SubscriptionKey { conn_id: conn.conn_id, sub_id: sub_id.clone() };
subscribers.lock().insert(uniq_sub, (method_sink.clone(), conn_rx));
method_sink.send_response(id.clone(), &sub_id);
let sink = SubscriptionSink {
inner: method_sink.clone(),
method: notif_method_name,
subscribers: subscribers.clone(),
uniq_sub: SubscriptionKey { conn_id: conn.conn_id, sub_id },
is_connected: Some(conn_tx),
if let Err(err) = callback(params, sink, ctx.clone()) {
"subscribe call '{}' failed: {:?}, request id={:?}",
subscribe_method_name,
err,
id
);
method_sink.send_error(id, ErrorCode::ServerError(CALL_EXECUTION_FAILED_CODE).into())
} else {
true
self.methods.mut_callbacks().insert(
MethodCallback::new_subscription(Arc::new(move |id, params, sink, conn| {
let sub_id = match params.one::<RpcSubscriptionId>() {
Ok(sub_id) => sub_id,
Err(_) => {
"unsubscribe call '{}' failed: couldn't parse subscription id={:?} request id={:?}",
return sink.send_response(id, false);
let sub_id = sub_id.into_owned();
let result = subscribers
.lock()
.remove(&SubscriptionKey { conn_id: conn.conn_id, sub_id: sub_id.clone() })
.is_some();
sink.send_response(id, result)
/// Register an alias for an existing_method. Alias uniqueness is enforced.
pub fn register_alias(&mut self, alias: &'static str, existing_method: &'static str) -> Result<(), Error> {
self.methods.verify_method_name(alias)?;
let callback = match self.methods.callbacks.get(existing_method) {
Some(callback) => callback.clone(),
None => return Err(Error::MethodNotFound(existing_method.into())),
};
self.methods.mut_callbacks().insert(alias, callback);
/// Represents a single subscription.
#[derive(Debug)]
pub struct SubscriptionSink {
/// Sink.
/// Get notified when subscribers leave so we can exit
close_notify: Option<Arc<Notify>>,
/// Unique subscription.
uniq_sub: SubscriptionKey,
/// Shared Mutex of subscriptions for this method.
subscribers: Subscribers,
/// A type to track whether the subscription is active (the subscriber is connected).
///
/// None - implies that the subscription as been closed.
is_connected: Option<oneshot::Sender<()>>,
}
impl SubscriptionSink {
pub fn send<T: Serialize>(&mut self, result: &T) -> Result<(), Error> {
if self.is_closed() {
return Err(Error::SubscriptionClosed(SubscriptionClosedReason::ConnectionReset.into()));
}
let msg = self.build_message(result)?;
self.inner_send(msg).map_err(Into::into)
/// Consumes the `SubscriptionSink` and reads data from the `stream` and sends back data on the subscription
/// when items gets produced by the stream.
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/// The underlying stream must produce `Result values, see [`futures_util::TryStream`] for further information.
///
/// Returns `Ok(())` if the stream or connection was terminated.
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/// Returns `Err(_)` immediately if the underlying stream returns an error or if an item from the stream could not be serialized.
///
/// # Examples
///
/// ```no_run
///
/// use jsonrpsee_core::server::rpc_module::RpcModule;
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/// use anyhow::anyhow;
///
/// let mut m = RpcModule::new(());
/// m.register_subscription("sub", "_", "unsub", |params, mut sink, _| {
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/// let stream = futures_util::stream::iter(vec![Ok(1_u32), Ok(2), Err("error on the stream")]);
/// // This will return send `[Ok(1_u32), Ok(2_u32), Err(Error::SubscriptionClosed))]` to the subscriber
/// // because after the `Err(_)` the stream is terminated.
/// tokio::spawn(sink.pipe_from_try_stream(stream));
/// Ok(())
/// });
/// ```
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pub async fn pipe_from_try_stream<S, T, E>(mut self, mut stream: S) -> Result<(), Error>
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S: TryStream<Ok = T, Error = E> + Unpin,
T: Serialize,
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E: std::fmt::Display,
if let Some(close_notify) = self.close_notify.clone() {
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let mut stream_item = stream.try_next();
let closed_fut = close_notify.notified();
pin_mut!(closed_fut);
loop {
match futures_util::future::select(stream_item, closed_fut).await {
// The app sent us a value to send back to the subscribers
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Either::Left((Ok(Some(result)), next_closed_fut)) => {
match self.send(&result) {
Ok(_) => (),
Err(Error::SubscriptionClosed(close_reason)) => {
self.close(&close_reason);
break Ok(());
}
Err(err) => {
break Err(err);
}
};
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stream_item = stream.try_next();
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Either::Left((Err(e), _)) => {
let close_reason = SubscriptionClosedReason::Server(e.to_string()).into();
self.close(&close_reason);
break Err(Error::SubscriptionClosed(close_reason));
}
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Either::Left((Ok(None), _)) => break Ok(()),
// The subscriber went away without telling us.
Either::Right(((), _)) => {
self.close(&SubscriptionClosed::new(SubscriptionClosedReason::ConnectionReset));
break Ok(());
}
}
}
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/// Similar to [`SubscriptionSink::pipe_from_try_stream`] but it doesn't require the stream return `Result`.
///
/// Warning: it's possible to pass in a stream that returns `Result` if `Result: Serialize` is satisfied
/// but it won't cancel the stream when an error occurs. If you want the stream to be canceled when an
/// error occurs use [`SubscriptionSink::pipe_from_try_stream`] instead.
///
/// # Examples
///
/// ```no_run
///
/// use jsonrpsee_core::server::rpc_module::RpcModule;
///
/// let mut m = RpcModule::new(());
/// m.register_subscription("sub", "_", "unsub", |params, mut sink, _| {
/// let stream = futures_util::stream::iter(vec![1, 2, 3]);
/// tokio::spawn(sink.pipe_from_stream(stream));
/// Ok(())
/// });
/// ```
pub async fn pipe_from_stream<S, T>(self, stream: S) -> Result<(), Error>
where
S: Stream<Item = T> + Unpin,
T: Serialize,
{
self.pipe_from_try_stream::<_, _, Error>(stream.map(|item| Ok(item))).await
}
/// Returns whether this channel is closed without needing a context.
pub fn is_closed(&self) -> bool {
self.inner.is_closed() || self.close_notify.is_none()
fn build_message<T: Serialize>(&self, result: &T) -> Result<String, Error> {
serde_json::to_string(&SubscriptionResponse::new(
self.method.into(),
SubscriptionPayload { subscription: self.uniq_sub.sub_id.clone(), result },
.map_err(Into::into)
fn inner_send(&mut self, msg: String) -> Result<(), Error> {
let res = match self.is_connected.as_ref() {
Some(conn) if !conn.is_canceled() => {
// unbounded send only fails if the receiver has been dropped.
self.inner.send_raw(msg).map_err(|_| Some(SubscriptionClosedReason::ConnectionReset))
Some(_) => Err(Some(SubscriptionClosedReason::Unsubscribed)),
// NOTE(niklasad1): this should be unreachable, after the first error is detected the subscription is closed.
// The subscription was already closed by the client
// Close down the subscription but don't send a message to the client.
if res.is_err() {
self.inner_close(None);
let err = e.unwrap_or_else(|| SubscriptionClosedReason::Server("Close reason unknown".to_string()));
Error::SubscriptionClosed(err.into())
/// Close the subscription sink with a customized error message.
pub fn close_with_custom_message(&mut self, msg: &str) {
let close_reason = SubscriptionClosedReason::Server(msg.to_string()).into();
self.inner_close(Some(&close_reason));
/// Close the subscription sink with the provided [`SubscriptionClosed`].
pub fn close(&mut self, close_reason: &SubscriptionClosed) {
self.inner_close(Some(close_reason));
}
fn inner_close(&mut self, maybe_close: Option<&SubscriptionClosed>) {
self.is_connected.take();
if let Some((sink, _)) = self.subscribers.lock().remove(&self.uniq_sub) {
tracing::debug!("Closing subscription: {:?} reason: {:?}", self.uniq_sub.sub_id, maybe_close);
let closed_by_server =
maybe_close.map_or(false, |c| matches!(c.close_reason(), SubscriptionClosedReason::Server(_)));
if closed_by_server {
let msg = self.build_message(&maybe_close).expect("valid json infallible; qed");
let _ = sink.send_raw(msg);
}
impl Drop for SubscriptionSink {
fn drop(&mut self) {
let err = SubscriptionClosedReason::Server("No close reason provided".into()).into();
self.inner_close(Some(&err));
/// Wrapper struct that maintains a subscription "mainly" for testing.
pub struct Subscription {
rx: mpsc::UnboundedReceiver<String>,
sub_id: RpcSubscriptionId<'static>,
impl Subscription {
/// Close the subscription channel.
pub fn close(&mut self) {
tracing::trace!("[Subscription::close] Notifying");
if let Some(n) = self.close_notify.take() {
n.notify_one()
}
}
/// Get the subscription ID
pub fn subscription_id(&self) -> &RpcSubscriptionId {
&self.sub_id
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/// Returns `Some((val, sub_id))` for the next element of type T from the underlying stream,
/// otherwise `None` if the subscription was closed.
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/// # Panics
///
/// If the decoding the value as `T` fails.
pub async fn next<T: DeserializeOwned>(&mut self) -> Option<Result<(T, RpcSubscriptionId<'static>), Error>> {
if self.close_notify.is_none() {
tracing::debug!("[Subscription::next] Closed.");
return Some(Err(Error::SubscriptionClosed(SubscriptionClosedReason::ConnectionReset.into())));
}
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let raw = self.rx.next().await?;
let res = match serde_json::from_str::<SubscriptionResponse<T>>(&raw) {
Ok(r) => Ok((r.params.result, r.params.subscription.into_owned())),
Err(_) => match serde_json::from_str::<SubscriptionResponse<SubscriptionClosed>>(&raw) {
Ok(e) => Err(Error::SubscriptionClosed(e.params.result)),
Err(e) => Err(e.into()),
},
};
impl Drop for Subscription {
fn drop(&mut self) {
self.close();
}
}