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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.
//! Example that shows how to broadcast to all active subscriptions using `tokio::sync::broadcast`.
use futures::future;
use futures::StreamExt;
use jsonrpsee::core::client::{Subscription, SubscriptionClientT};
use jsonrpsee::rpc_params;
use jsonrpsee::ws_client::WsClientBuilder;
use jsonrpsee::ws_server::{RpcModule, WsServerBuilder};
use tokio::sync::broadcast;
use tokio_stream::wrappers::BroadcastStream;
const NUM_SUBSCRIPTION_RESPONSES: usize = 5;
async fn main() -> anyhow::Result<()> {
tracing_subscriber::FmtSubscriber::builder()
.with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
.try_init()
.expect("setting default subscriber failed");
let addr = run_server().await?;
let url = format!("ws://{}", addr);
let client1 = WsClientBuilder::default().build(&url).await?;
let client2 = WsClientBuilder::default().build(&url).await?;
let sub1: Subscription<i32> = client1.subscribe("subscribe_hello", rpc_params![], "unsubscribe_hello").await?;
let sub2: Subscription<i32> = client2.subscribe("subscribe_hello", rpc_params![], "unsubscribe_hello").await?;
let fut1 = sub1.take(NUM_SUBSCRIPTION_RESPONSES).for_each(|r| async move { tracing::info!("sub1 rx: {:?}", r) });
let fut2 = sub2.take(NUM_SUBSCRIPTION_RESPONSES).for_each(|r| async move { tracing::info!("sub2 rx: {:?}", r) });
future::join(fut1, fut2).await;
async fn run_server() -> anyhow::Result<SocketAddr> {
let server = WsServerBuilder::default().build("127.0.0.1:0").await?;
let (tx, _rx) = broadcast::channel(16);
let tx2 = tx.clone();
std::thread::spawn(move || produce_items(tx2));
module.register_subscription("subscribe_hello", "s_hello", "unsubscribe_hello", move |_, sink, _| {
let rx = BroadcastStream::new(tx.clone().subscribe());
tokio::spawn(async move {
let _ = sink.pipe_from_try_stream(rx).await;
});
Ok(())
})?;
// Naive example that broadcasts the produced values to all active subscribers.
fn produce_items(tx: broadcast::Sender<usize>) {
for c in 1..=100 {
std::thread::sleep(std::time::Duration::from_secs(1));
// This might fail if no receivers are alive, could occur if no subscriptions are active...
// Also be aware that this will succeed when at least one receiver is alive
// Thus, clients connecting at different point in time will not receive
// the items sent before the subscription got established.
let _ = tx.send(c);
}
}