jsonrpc_macros/
pubsub.rs

1//! PUB-SUB auto-serializing structures.
2
3use std::marker::PhantomData;
4
5use jsonrpc_core as core;
6use jsonrpc_pubsub as pubsub;
7use serde;
8use util::to_value;
9
10use self::core::futures::{self, Sink as FuturesSink};
11
12pub use self::pubsub::SubscriptionId;
13
14/// New PUB-SUB subcriber.
15#[derive(Debug)]
16pub struct Subscriber<T, E = core::Error> {
17	subscriber: pubsub::Subscriber,
18	_data: PhantomData<(T, E)>,
19}
20
21impl<T, E> Subscriber<T, E> {
22	/// Wrap non-typed subscriber.
23	pub fn new(subscriber: pubsub::Subscriber) -> Self {
24		Subscriber {
25			subscriber: subscriber,
26			_data: PhantomData,
27		}
28	}
29
30	/// Reject subscription with given error.
31	pub fn reject(self, error: core::Error) -> Result<(), ()> {
32		self.subscriber.reject(error)
33	}
34
35	/// Assign id to this subscriber.
36	/// This method consumes `Subscriber` and returns `Sink`
37	/// if the connection is still open or error otherwise.
38	pub fn assign_id(self, id: SubscriptionId) -> Result<Sink<T, E>, ()> {
39		let sink = self.subscriber.assign_id(id.clone())?;
40		Ok(Sink {
41			id: id,
42			sink: sink,
43			buffered: None,
44			_data: PhantomData,
45		})
46	}
47}
48
49/// Subscriber sink.
50#[derive(Debug, Clone)]
51pub struct Sink<T, E = core::Error> {
52	sink: pubsub::Sink,
53	id: SubscriptionId,
54	buffered: Option<core::Params>,
55	_data: PhantomData<(T, E)>,
56}
57
58impl<T: serde::Serialize, E: serde::Serialize> Sink<T, E> {
59	/// Sends a notification to the subscriber.
60	pub fn notify(&self, val: Result<T, E>) -> pubsub::SinkResult {
61		self.sink.notify(self.val_to_params(val))
62	}
63
64	fn val_to_params(&self, val: Result<T, E>) -> core::Params {
65		let id = self.id.clone().into();
66		let val = val.map(to_value).map_err(to_value);
67
68		core::Params::Map(vec![
69			("subscription".to_owned(), id),
70			match val {
71				Ok(val) => ("result".to_owned(), val),
72				Err(err) => ("error".to_owned(), err),
73			},
74		].into_iter().collect())
75	}
76
77	fn poll(&mut self) -> futures::Poll<(), pubsub::TransportError> {
78		if let Some(item) = self.buffered.take() {
79			let result = self.sink.start_send(item)?;
80			if let futures::AsyncSink::NotReady(item) = result {
81				self.buffered = Some(item);
82			}
83		}
84
85		if self.buffered.is_some() {
86			Ok(futures::Async::NotReady)
87		} else {
88			Ok(futures::Async::Ready(()))
89		}
90	}
91}
92
93impl<T: serde::Serialize, E: serde::Serialize> futures::sink::Sink for Sink<T, E> {
94	type SinkItem = Result<T, E>;
95	type SinkError = pubsub::TransportError;
96
97	fn start_send(&mut self, item: Self::SinkItem) -> futures::StartSend<Self::SinkItem, Self::SinkError> {
98		// Make sure to always try to process the buffered entry.
99		// Since we're just a proxy to real `Sink` we don't need
100		// to schedule a `Task` wakeup. It will be done downstream.
101		if self.poll()?.is_not_ready() {
102			return Ok(futures::AsyncSink::NotReady(item));
103		}
104
105		let val = self.val_to_params(item);
106		self.buffered = Some(val);
107		self.poll()?;
108
109		Ok(futures::AsyncSink::Ready)
110	}
111
112	fn poll_complete(&mut self) -> futures::Poll<(), Self::SinkError> {
113		self.poll()?;
114		self.sink.poll_complete()
115	}
116
117	fn close(&mut self) -> futures::Poll<(), Self::SinkError> {
118		self.poll()?;
119		self.sink.close()
120	}
121}
jsonrpc_macros/pubsub.rs

jsonrpc_macros/
pubsub.rs
