rpc_module.rs

				}
				Either::Left((Ok(None), _)) => break SubscriptionClosed::Success,
				Either::Right((_, _)) => {
					break SubscriptionClosed::RemotePeerAborted;
				}
			}
		}
	}

	/// 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_usize, 2, 3]);
	///     tokio::spawn(async move { sink.pipe_from_stream(stream).await; });
	///     Ok(())
	/// });
	/// ```
	pub async fn pipe_from_stream<S, T>(&mut self, stream: S) -> SubscriptionClosed
	where
		S: Stream<Item = T> + Unpin,
		T: Serialize,
	{
		self.pipe_from_try_stream::<_, _, Error>(stream.map(|item| Ok(item))).await
	}

	/// Returns whether the subscription is closed.
	pub fn is_closed(&self) -> bool {
		self.inner.is_closed() || self.close_notify.is_none() || !self.is_active_subscription()
	}

	fn is_active_subscription(&self) -> bool {
		match self.unsubscribe.as_ref() {
			Some(unsubscribe) => !unsubscribe.has_changed().is_err(),
			_ => false,
		}
	}

	fn answer_subscription(&self, response: MethodResponse, subscribe_call: oneshot::Sender<MethodResponse>) -> bool {
		let ws_send = self.inner.send_raw(response.result.clone()).is_ok();
		let middleware_call = subscribe_call.send(response).is_ok();

		ws_send && middleware_call
	}

	fn build_message<T: Serialize>(&self, result: &T) -> Result<String, serde_json::Error> {
		serde_json::to_string(&SubscriptionResponse::new(
			self.method.into(),
			SubscriptionPayload { subscription: self.uniq_sub.sub_id.clone(), result },
		))
		.map_err(Into::into)
	}

	fn build_error_message<T: Serialize>(&self, error: &T) -> Result<String, serde_json::Error> {
		serde_json::to_string(&SubscriptionError::new(
			self.method.into(),
			SubscriptionPayloadError { subscription: self.uniq_sub.sub_id.clone(), error },
		))
		.map_err(Into::into)
	}

	/// Close the subscription, sending a notification with a special `error` field containing the provided error.
	///
	/// This can be used to signal an actual error, or just to signal that the subscription has been closed,
	/// depending on your preference.
	///
	/// If you'd like to to close the subscription without sending an error, just drop it and don't call this method.
	///
	///
	/// ```json
	/// {
	///  "jsonrpc": "2.0",
	///  "method": "<method>",
	///  "params": {
	///    "subscription": "<subscriptionID>",
	///    "error": { "code": <code from error>, "message": <message from error>, "data": <data from error> }
	///    }
	///  }
	/// }
	/// ```
	///
	pub fn close(self, err: impl Into<ErrorObjectOwned>) -> bool {
		if self.is_active_subscription() {
			if let Some((sink, _)) = self.subscribers.lock().remove(&self.uniq_sub) {
				tracing::debug!("Closing subscription: {:?}", self.uniq_sub.sub_id);

				let msg = self.build_error_message(&err.into()).expect("valid json infallible; qed");
				return sink.send_raw(msg).is_ok();
			}
		}
		false
	}
}

impl Drop for SubscriptionSink {
	fn drop(&mut self) {
		if let Some((id, subscribe_call)) = self.id.take() {
			// Subscription was never accepted / rejected. As such,
			// we default to assuming that the params were invalid,
			// because that's how the previous PendingSubscription logic
			// worked.
			let err = MethodResponse::error(id, ErrorObject::from(ErrorCode::InvalidParams));
			self.answer_subscription(err, subscribe_call);
		} else if self.is_active_subscription() {
			self.subscribers.lock().remove(&self.uniq_sub);
		}
	}
}

/// Wrapper struct that maintains a subscription "mainly" for testing.
#[derive(Debug)]
pub struct Subscription {
	close_notify: Option<SubscriptionPermit>,
	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.handle().notify_one()
		}
	}

	/// Get the subscription ID
	pub fn subscription_id(&self) -> &RpcSubscriptionId {
		&self.sub_id
	}

	/// Check whether the subscription is closed.
	pub fn is_closed(&self) -> bool {
		self.close_notify.is_none()
	}

	/// Returns `Some((val, sub_id))` for the next element of type T from the underlying stream,
	/// otherwise `None` if the subscription was closed.
	///
	/// # 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 None;
		}
		let raw = self.rx.next().await?;

		tracing::debug!("[Subscription::next]: rx {}", raw);
		let res = match serde_json::from_str::<SubscriptionResponse<T>>(&raw) {
			Ok(r) => Some(Ok((r.params.result, r.params.subscription.into_owned()))),
			Err(e) => match serde_json::from_str::<SubscriptionError<serde_json::Value>>(&raw) {
				Ok(_) => None,
				Err(_) => Some(Err(e.into())),
			},
		};
		res
	}
}

impl Drop for Subscription {
	fn drop(&mut self) {
		self.close();
	}
}