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// Copyright 2019-2022 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.
//! This example utilizes the `ProxyRequest` layer for redirecting
//! `GET /path` requests to internal RPC methods.
//!
//! The RPC server registers a method named `system_health` which
//! returns `serde_json::Value`. Redirect any `GET /health`
//! requests to the internal method, and return only the method's
//! response in the body (ie, without any jsonRPC 2.0 overhead).
//!
//! # Note
//!
//! This functionality is useful for services which would
//! like to query a certain `URI` path for statistics.
use hyper::{Body, Client, Request};
use std::net::SocketAddr;
use std::time::Duration;
use jsonrpsee::core::client::ClientT;
use jsonrpsee::http_client::HttpClientBuilder;
use jsonrpsee::http_server::middleware::proxy_get_request::ProxyGetRequestLayer;
use jsonrpsee::http_server::{HttpServerBuilder, HttpServerHandle, RpcModule};
#[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, _handler) = run_server().await?;
let url = format!("http://{}", addr);
// Use RPC client to get the response of `say_hello` method.
let client = HttpClientBuilder::default().build(&url)?;
let response: String = client.request("say_hello", None).await?;
println!("[main]: response: {:?}", response);
// Use hyper client to manually submit a `GET /health` request.
let http_client = Client::new();
let uri = format!("http://{}/health", addr);
let req = Request::builder().method("GET").uri(&uri).body(Body::empty())?;
println!("[main]: Submit proxy request: {:?}", req);
let res = http_client.request(req).await?;
println!("[main]: Received proxy response: {:?}", res);
// Interpret the response as String.
let bytes = hyper::body::to_bytes(res.into_body()).await.unwrap();
let out = String::from_utf8(bytes.to_vec()).unwrap();
println!("[main]: Interpret proxy response: {:?}", out);
assert_eq!(out.as_str(), "{\"health\":true}");
Ok(())
}
async fn run_server() -> anyhow::Result<(SocketAddr, HttpServerHandle)> {
// Custom tower service to handle the RPC requests
let service_builder = tower::ServiceBuilder::new()
// Proxy `GET /health` requests to internal `system_health` method.
.layer(ProxyGetRequestLayer::new("/health", "system_health")?)
.timeout(Duration::from_secs(2));
let server =
HttpServerBuilder::new().set_middleware(service_builder).build("127.0.0.1:0".parse::<SocketAddr>()?).await?;
let addr = server.local_addr()?;
let mut module = RpcModule::new(());
module.register_method("say_hello", |_, _| Ok("lo")).unwrap();
module.register_method("system_health", |_, _| Ok(serde_json::json!({ "health": true }))).unwrap();
let handler = server.start(module)?;
Ok((addr, handler))
}