RPC middleware: Informant & Client.keep_alive (#4384)

* Adding RPC informant structs

* RPC informant

* Middleware counting RPC requests

* Moving client keep_alive to middleware

dapps/src/lib.rs

@@ -70,9 +70,10 @@ use std::sync::{Arc, Mutex};
 use std::net::SocketAddr;
 use std::collections::HashMap;
 
-use ethcore_rpc::Metadata;
+use ethcore_rpc::{Metadata};
 use fetch::{Fetch, Client as FetchClient};
 use hash_fetch::urlhint::ContractClient;
+use jsonrpc_core::Middleware;
 use jsonrpc_core::reactor::RpcHandler;
 use router::auth::{Authorization, NoAuth, HttpBasicAuth};
 use parity_reactor::Remote;
@@ -179,7 +180,7 @@ impl<T: Fetch> ServerBuilder<T> {
 
 	/// Asynchronously start server with no authentication,
 	/// returns result with `Server` handle on success or an error.
-	pub fn start_unsecured_http(self, addr: &SocketAddr, handler: RpcHandler<Metadata>) -> Result<Server, ServerError> {
+	pub fn start_unsecured_http<S: Middleware<Metadata>>(self, addr: &SocketAddr, handler: RpcHandler<Metadata, S>) -> Result<Server, ServerError> {
 		let fetch = self.fetch_client()?;
 		Server::start_http(
 			addr,
@@ -199,7 +200,7 @@ impl<T: Fetch> ServerBuilder<T> {
 
 	/// Asynchronously start server with `HTTP Basic Authentication`,
 	/// return result with `Server` handle on success or an error.
-	pub fn start_basic_auth_http(self, addr: &SocketAddr, username: &str, password: &str, handler: RpcHandler<Metadata>) -> Result<Server, ServerError> {
+	pub fn start_basic_auth_http<S: Middleware<Metadata>>(self, addr: &SocketAddr, username: &str, password: &str, handler: RpcHandler<Metadata, S>) -> Result<Server, ServerError> {
 		let fetch = self.fetch_client()?;
 		Server::start_http(
 			addr,
@@ -258,11 +259,11 @@ impl Server {
 		}
 	}
 
-	fn start_http<A: Authorization + 'static, F: Fetch>(
+	fn start_http<A: Authorization + 'static, F: Fetch, T: Middleware<Metadata>>(
 		addr: &SocketAddr,
 		hosts: Option<Vec<String>>,
 		authorization: A,
-		handler: RpcHandler<Metadata>,
+		handler: RpcHandler<Metadata, T>,
 		dapps_path: PathBuf,
 		extra_dapps: Vec<PathBuf>,
 		signer_address: Option<(String, u16)>,

dapps/src/rpc.rs

@@ -18,11 +18,15 @@ use std::sync::{Arc, Mutex};
 use hyper;
 
 use ethcore_rpc::{Metadata, Origin};
+use jsonrpc_core::Middleware;
 use jsonrpc_core::reactor::RpcHandler;
 use jsonrpc_http_server::{Rpc, ServerHandler, PanicHandler, AccessControlAllowOrigin, HttpMetaExtractor};
 use endpoint::{Endpoint, EndpointPath, Handler};
 
-pub fn rpc(handler: RpcHandler<Metadata>, panic_handler: Arc<Mutex<Option<Box<Fn() -> () + Send>>>>) -> Box<Endpoint> {
+pub fn rpc<T: Middleware<Metadata>>(
+	handler: RpcHandler<Metadata, T>,
+	panic_handler: Arc<Mutex<Option<Box<Fn() -> () + Send>>>>,
+) -> Box<Endpoint> {
 	Box::new(RpcEndpoint {
 		handler: handler,
 		meta_extractor: Arc::new(MetadataExtractor),
@@ -33,15 +37,15 @@ pub fn rpc(handler: RpcHandler<Metadata>, panic_handler: Arc<Mutex<Option<Box<Fn
 	})
 }
 
-struct RpcEndpoint {
-	handler: RpcHandler<Metadata>,
+struct RpcEndpoint<T: Middleware<Metadata>> {
+	handler: RpcHandler<Metadata, T>,
 	meta_extractor: Arc<HttpMetaExtractor<Metadata>>,
 	panic_handler: Arc<Mutex<Option<Box<Fn() -> () + Send>>>>,
 	cors_domain: Option<Vec<AccessControlAllowOrigin>>,
 	allowed_hosts: Option<Vec<String>>,
 }
 
-impl Endpoint for RpcEndpoint {
+impl<T: Middleware<Metadata>> Endpoint for RpcEndpoint<T> {
 	fn to_async_handler(&self, _path: EndpointPath, control: hyper::Control) -> Box<Handler> {
 		let panic_handler = PanicHandler { handler: self.panic_handler.clone() };
 		Box::new(ServerHandler::new(

dapps/src/tests/rpc.rs

@@ -23,7 +23,7 @@ use tests::helpers::{serve_with_rpc, request};
 #[test]
 fn should_serve_rpc() {
 	// given
-	let mut io = MetaIoHandler::new();
+	let mut io = MetaIoHandler::default();
 	io.add_method("rpc_test", |_| {
 		Ok(Value::String("Hello World!".into()))
 	});
@@ -53,7 +53,7 @@ fn should_serve_rpc() {
 #[test]
 fn should_extract_metadata() {
 	// given
-	let mut io = MetaIoHandler::new();
+	let mut io = MetaIoHandler::default();
 	io.add_method_with_meta("rpc_test", |_params, meta: Metadata| {
 		assert_eq!(meta.dapp_id, Some("https://parity.io/".to_owned()));
 		assert_eq!(meta.origin, Origin::Dapps);
@@ -87,7 +87,7 @@ fn should_extract_metadata() {
 #[test]
 fn should_extract_metadata_from_custom_header() {
 	// given
-	let mut io = MetaIoHandler::new();
+	let mut io = MetaIoHandler::default();
 	io.add_method_with_meta("rpc_test", |_params, meta: Metadata| {
 		assert_eq!(meta.dapp_id, Some("https://parity.io/".to_owned()));
 		assert_eq!(meta.origin, Origin::Dapps);