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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 showing how to add multiple middlewares to the same server.
use jsonrpsee::{
rpc_params,
types::{middleware, traits::Client},
ws_client::WsClientBuilder,
ws_server::{RpcModule, WsServerBuilder},
};
use std::net::SocketAddr;
use std::process::Command;
use std::time::Instant;
/// Example middleware to measure call execution time.
#[derive(Clone)]
struct Timings;
impl middleware::Middleware for Timings {
type Instant = Instant;
fn on_request(&self) -> Self::Instant {
Instant::now()
}
fn on_call(&self, name: &str) {
println!("[Timings] They called '{}'", name);
}
fn on_result(&self, name: &str, succeess: bool, started_at: Self::Instant) {
println!("[Timings] call={}, worked? {}, duration {:?}", name, succeess, started_at.elapsed());
}
fn on_response(&self, started_at: Self::Instant) {
println!("[Timings] Response duration {:?}", started_at.elapsed());
}
}
/// Example middleware to keep a watch on the number of total threads started in the system.
#[derive(Clone)]
struct ThreadWatcher;
impl ThreadWatcher {
// Count the number of threads visible to this process. Counts the lines of `ps -eL` and equivalent minus one (the header).
// Cribbed from the `palaver` crate.
fn count_threads() -> usize {
let out = if cfg!(any(target_os = "linux", target_os = "android")) {
Command::new("ps").arg("-eL").output().expect("failed to execute process")
} else if cfg!(any(target_os = "macos", target_os = "ios")) {
Command::new("ps").arg("-eM").output().expect("failed to execute process")
} else {
unimplemented!()
};
out.stdout.split(|&x| x == b'\n').skip(1).filter(|x| !x.is_empty()).count()
}
}
impl middleware::Middleware for ThreadWatcher {
type Instant = isize;
fn on_request(&self) -> Self::Instant {
let threads = Self::count_threads();
println!("[ThreadWatcher] Threads running on the machine at the start of a call: {}", threads);
threads as isize
}
fn on_response(&self, started_at: Self::Instant) {
let current_nr_threads = Self::count_threads() as isize;
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println!("[ThreadWatcher] Request started {} threads", current_nr_threads - started_at);
}
}
#[tokio::main]
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 client = WsClientBuilder::default().build(&url).await?;
let response: String = client.request("say_hello", None).await?;
println!("response: {:?}", response);
let _response: Result<String, _> = client.request("unknown_method", None).await;
let _ = client.request::<String>("say_hello", None).await?;
let _ = client.request::<()>("thready", rpc_params![4]).await?;
Ok(())
}
async fn run_server() -> anyhow::Result<SocketAddr> {
let server = WsServerBuilder::new().set_middleware((Timings, ThreadWatcher)).build("127.0.0.1:0").await?;
let mut module = RpcModule::new(());
module.register_method("say_hello", |_, _| Ok("lo"))?;
module.register_method("thready", |params, _| {
let thread_count: usize = params.one().unwrap();
for _ in 0..thread_count {
std::thread::spawn(|| std::thread::sleep(std::time::Duration::from_secs(1)));
}
Ok(())
})?;
let addr = server.local_addr()?;
server.start(module)?;
Ok(addr)
}