Crate jsonrpc_derive

High level, typed wrapper for jsonrpc_core.

Enables creation of "Service" objects grouping a set of RPC methods together in a typed manner.

Example

use jsonrpc_derive::rpc;
use jsonrpc_core::{IoHandler, Result, BoxFuture};
use jsonrpc_core::futures::future;

#[rpc(server)]
pub trait Rpc {
	#[rpc(name = "protocolVersion")]
	fn protocol_version(&self) -> Result<String>;

	#[rpc(name = "add")]
	fn add(&self, a: u64, b: u64) -> Result<u64>;

	#[rpc(name = "callAsync")]
	fn call(&self, a: u64) -> BoxFuture<Result<String>>;
}

struct RpcImpl;
impl Rpc for RpcImpl {
	fn protocol_version(&self) -> Result<String> {
		Ok("version1".into())
	}

	fn add(&self, a: u64, b: u64) -> Result<u64> {
		Ok(a + b)
	}

	fn call(&self, _: u64) -> BoxFuture<Result<String>> {
		Box::pin(future::ready(Ok("OK".to_owned()).into()))
	}
}

fn main() {
  let mut io = IoHandler::new();
  let rpc = RpcImpl;

  io.extend_with(rpc.to_delegate());
}

Pub/Sub Example

Each subscription must have subscribe and unsubscribe methods. They can have any name but must be annotated with subscribe or unsubscribe and have a matching unique subscription name.

use std::thread;
use std::sync::{atomic, Arc, RwLock};
use std::collections::HashMap;

use jsonrpc_core::{Error, ErrorCode, Result};
use jsonrpc_derive::rpc;
use jsonrpc_pubsub::{Session, PubSubHandler, SubscriptionId, typed::{Subscriber, Sink}};

#[rpc]
pub trait Rpc {
	type Metadata;

	/// Hello subscription
	#[pubsub(
		subscription = "hello",
		subscribe,
		name = "hello_subscribe",
		alias("hello_sub")
	)]
	fn subscribe(&self, _: Self::Metadata, _: Subscriber<String>, param: u64);

	/// Unsubscribe from hello subscription.
	#[pubsub(
		subscription = "hello",
		unsubscribe,
		name = "hello_unsubscribe"
	)]
	fn unsubscribe(&self, _: Option<Self::Metadata>, _: SubscriptionId) -> Result<bool>;
}


#[derive(Default)]
struct RpcImpl {
	uid: atomic::AtomicUsize,
	active: Arc<RwLock<HashMap<SubscriptionId, Sink<String>>>>,
}
impl Rpc for RpcImpl {
	type Metadata = Arc<Session>;

	fn subscribe(&self, _meta: Self::Metadata, subscriber: Subscriber<String>, param: u64) {
		if param != 10 {
			subscriber.reject(Error {
				code: ErrorCode::InvalidParams,
				message: "Rejecting subscription - invalid parameters provided.".into(),
				data: None,
			}).unwrap();
			return;
		}

		let id = self.uid.fetch_add(1, atomic::Ordering::SeqCst);
		let sub_id = SubscriptionId::Number(id as u64);
		let sink = subscriber.assign_id(sub_id.clone()).unwrap();
		self.active.write().unwrap().insert(sub_id, sink);
	}

	fn unsubscribe(&self, _meta: Option<Self::Metadata>, id: SubscriptionId) -> Result<bool> {
		let removed = self.active.write().unwrap().remove(&id);
		if removed.is_some() {
			Ok(true)
		} else {
			Err(Error {
				code: ErrorCode::InvalidParams,
				message: "Invalid subscription.".into(),
				data: None,
			})
		}
	}
}

fn main() {
  let mut io = jsonrpc_core::MetaIoHandler::default();
  io.extend_with(RpcImpl::default().to_delegate());

  let server_builder = jsonrpc_tcp_server::ServerBuilder::with_meta_extractor(
	io,
	|request: &jsonrpc_tcp_server::RequestContext| Arc::new(Session::new(request.sender.clone()))
  );
  let server = server_builder
	.start(&"127.0.0.1:3030".parse().unwrap())
	.expect("Unable to start TCP server");

  // The server spawns a separate thread. Dropping the `server` handle causes it to close.
  // Uncomment the line below to keep the server running in your example.
  // server.wait();
}

Client Example

use jsonrpc_core_client::transports::local;
use jsonrpc_core::futures::{self, future};
use jsonrpc_core::{IoHandler, Result, BoxFuture};
use jsonrpc_derive::rpc;

/// Rpc trait
#[rpc]
pub trait Rpc {
	/// Returns a protocol version
	#[rpc(name = "protocolVersion")]
	fn protocol_version(&self) -> Result<String>;

	/// Adds two numbers and returns a result
	#[rpc(name = "add", alias("callAsyncMetaAlias"))]
	fn add(&self, a: u64, b: u64) -> Result<u64>;

	/// Performs asynchronous operation
	#[rpc(name = "callAsync")]
	fn call(&self, a: u64) -> BoxFuture<Result<String>>;
}

struct RpcImpl;

impl Rpc for RpcImpl {
	fn protocol_version(&self) -> Result<String> {
		Ok("version1".into())
	}

	fn add(&self, a: u64, b: u64) -> Result<u64> {
		Ok(a + b)
	}

	fn call(&self, _: u64) -> BoxFuture<Result<String>> {
		Box::pin(future::ready(Ok("OK".to_owned())))
	}
}

fn main() {
	let exec = futures::executor::ThreadPool::new().unwrap();
	exec.spawn_ok(run())
}
async fn run() {
	let mut io = IoHandler::new();
	io.extend_with(RpcImpl.to_delegate());

	let (client, server) = local::connect::<RpcClient, _, _>(io);
	let res = client.add(5, 6).await.unwrap();
	println!("5 + 6 = {}", res);
	server.await.unwrap()
}

Attribute Macros

rpc	Apply #[rpc] to a trait, and a to_delegate method is generated which wires up methods decorated with #[rpc] or #[pubsub] attributes. Attach the delegate to an IoHandler and the methods are now callable via JSON-RPC.