Option to disable keep alive for JSON-RPC http transport (#9848)

* Keep alive jsonrpc CLI option.

* Update to latest json-rpc.

* Keep alive flag.

parity/cli/mod.rs

@@ -467,6 +467,10 @@ usage! {
 			"--no-jsonrpc",
 			"Disable the HTTP JSON-RPC API server.",
 
+			FLAG flag_jsonrpc_no_keep_alive: (bool) = false, or |c: &Config| c.rpc.as_ref()?.keep_alive,
+			"--jsonrpc-no-keep-alive",
+			"Disable HTTP/1.1 keep alive header. Disabling keep alive will prevent re-using the same TCP connection to fire multiple requests, recommended when using one request per connection.",
+
 			ARG arg_jsonrpc_port: (u16) = 8545u16, or |c: &Config| c.rpc.as_ref()?.port.clone(),
 			"--jsonrpc-port=[PORT]",
 			"Specify the port portion of the HTTP JSON-RPC API server.",
@@ -1219,6 +1223,7 @@ struct Rpc {
 	server_threads: Option<usize>,
 	processing_threads: Option<usize>,
 	max_payload: Option<usize>,
+	keep_alive: Option<bool>,
 }
 
 #[derive(Default, Debug, PartialEq, Deserialize)]
@@ -1676,6 +1681,7 @@ mod tests {
 			// -- API and Console Options
 			// RPC
 			flag_no_jsonrpc: false,
+			flag_jsonrpc_no_keep_alive: false,
 			arg_jsonrpc_port: 8545u16,
 			arg_jsonrpc_interface: "local".into(),
 			arg_jsonrpc_cors: "null".into(),
@@ -1958,6 +1964,7 @@ mod tests {
 				server_threads: None,
 				processing_threads: None,
 				max_payload: None,
+				keep_alive: None,
 			}),
 			ipc: Some(Ipc {
 				disable: None,

parity/configuration.rs

@@ -855,6 +855,7 @@ impl Configuration {
 				Some(max) if max > 0 => max as usize,
 				_ => 5usize,
 			},
+			keep_alive: !self.args.flag_jsonrpc_no_keep_alive,
 		};
 
 		Ok(conf)

parity/rpc.rs

@@ -44,6 +44,7 @@ pub struct HttpConfiguration {
 	pub server_threads: usize,
 	pub processing_threads: usize,
 	pub max_payload: usize,
+	pub keep_alive: bool,
 }
 
 impl Default for HttpConfiguration {
@@ -58,6 +59,7 @@ impl Default for HttpConfiguration {
 			server_threads: 1,
 			processing_threads: 4,
 			max_payload: 5,
+			keep_alive: true,
 		}
 	}
 }
@@ -218,6 +220,7 @@ pub fn new_http<D: rpc_apis::Dependencies>(
 		rpc::RpcExtractor,
 		conf.server_threads,
 		conf.max_payload,
+		conf.keep_alive,
 	);
 
 	match start_result {

rpc/src/lib.rs

@@ -137,6 +137,7 @@ pub fn start_http<M, S, H, T>(
 	extractor: T,
 	threads: usize,
 	max_payload: usize,
+	keep_alive: bool,
 ) -> ::std::io::Result<HttpServer> where
 	M: jsonrpc_core::Metadata,
 	S: jsonrpc_core::Middleware<M>,
@@ -145,6 +146,7 @@ pub fn start_http<M, S, H, T>(
 {
 	let extractor = http_common::MetaExtractor::new(extractor);
 	Ok(http::ServerBuilder::with_meta_extractor(handler, extractor)
+		.keep_alive(keep_alive)
 		.threads(threads)
 		.cors(cors_domains.into())
 		.allowed_hosts(allowed_hosts.into())
@@ -163,6 +165,7 @@ pub fn start_http_with_middleware<M, S, H, T, R>(
 	middleware: R,
 	threads: usize,
 	max_payload: usize,
+	keep_alive: bool,
 ) -> ::std::io::Result<HttpServer> where
 	M: jsonrpc_core::Metadata,
 	S: jsonrpc_core::Middleware<M>,
@@ -172,6 +175,7 @@ pub fn start_http_with_middleware<M, S, H, T, R>(
 {
 	let extractor = http_common::MetaExtractor::new(extractor);
 	Ok(http::ServerBuilder::with_meta_extractor(handler, extractor)
+		.keep_alive(keep_alive)
 		.threads(threads)
 		.cors(cors_domains.into())
 		.allowed_hosts(allowed_hosts.into())

rpc/src/tests/rpc.rs

@@ -40,6 +40,7 @@ fn serve(handler: Option<MetaIoHandler<Metadata>>) -> Server<HttpServer> {
 		},
 		1,
 		5,
+		false,
 	).unwrap())
 }
 

rpc/src/v1/extractors.rs

@@ -218,9 +218,10 @@ impl<M: core::Middleware<Metadata>> WsDispatcher<M> {
 
 impl<M: core::Middleware<Metadata>> core::Middleware<Metadata> for WsDispatcher<M> {
 	type Future = Either<
-		core::FutureRpcResult<M::Future>,
+		core::FutureRpcResult<M::Future, M::CallFuture>,
 		core::FutureResponse,
 	>;
+	type CallFuture = core::middleware::NoopCallFuture;
 
 	fn on_request<F, X>(&self, request: core::Request, meta: Metadata, process: F)
 		-> Either<Self::Future, X>

rpc/src/v1/informant.rs

@@ -205,6 +205,7 @@ impl<T: ActivityNotifier> Middleware<T> {
 
 impl<M: core::Metadata, T: ActivityNotifier> core::Middleware<M> for Middleware<T> {
 	type Future = core::FutureResponse;
+	type CallFuture = core::middleware::NoopCallFuture;
 
 	fn on_request<F, X>(&self, request: core::Request, meta: M, process: F) -> Either<Self::Future, X> where
 		F: FnOnce(core::Request, M) -> X,