RPC Middleware & Get/Set dapp-specific accounts

dapps/Cargo.toml

@@ -12,8 +12,8 @@ build = "build.rs"
 rand = "0.3.14"
 log = "0.3"
 env_logger = "0.3"
-jsonrpc-core = "3.0"
-jsonrpc-http-server = { git = "https://github.com/ethcore/jsonrpc-http-server.git" }
+jsonrpc-core = { git = "https://github.com/ethcore/jsonrpc.git" }
+jsonrpc-http-server = { git = "https://github.com/ethcore/jsonrpc.git" }
 hyper = { default-features = false, git = "https://github.com/ethcore/hyper" }
 unicase = "1.3"
 url = "1.0"

dapps/src/rpc.rs

@@ -16,13 +16,14 @@
 
 use std::sync::{Arc, Mutex};
 use hyper;
-use jsonrpc_core::IoHandler;
-use jsonrpc_http_server::{ServerHandler, PanicHandler, AccessControlAllowOrigin};
+
+use jsonrpc_core::{IoHandler, ResponseHandler, Request, Response};
+use jsonrpc_http_server::{ServerHandler, PanicHandler, AccessControlAllowOrigin, RpcHandler};
 use endpoint::{Endpoint, EndpointPath, Handler};
 
 pub fn rpc(handler: Arc<IoHandler>, panic_handler: Arc<Mutex<Option<Box<Fn() -> () + Send>>>>) -> Box<Endpoint> {
 	Box::new(RpcEndpoint {
-		handler: handler,
+		handler: Arc::new(RpcMiddleware::new(handler)),
 		panic_handler: panic_handler,
 		cors_domain: None,
 		// NOTE [ToDr] We don't need to do any hosts validation here. It's already done in router.
@@ -31,7 +32,7 @@ pub fn rpc(handler: Arc<IoHandler>, panic_handler: Arc<Mutex<Option<Box<Fn() ->
 }
 
 struct RpcEndpoint {
-	handler: Arc<IoHandler>,
+	handler: Arc<RpcMiddleware>,
 	panic_handler: Arc<Mutex<Option<Box<Fn() -> () + Send>>>>,
 	cors_domain: Option<Vec<AccessControlAllowOrigin>>,
 	allowed_hosts: Option<Vec<String>>,
@@ -49,3 +50,88 @@ impl Endpoint for RpcEndpoint {
 		))
 	}
 }
+
+const MIDDLEWARE_METHOD: &'static str = "eth_accounts";
+
+struct RpcMiddleware {
+	handler: Arc<IoHandler>,
+}
+
+impl RpcMiddleware {
+	fn new(handler: Arc<IoHandler>) -> Self {
+		RpcMiddleware {
+			handler: handler,
+		}
+	}
+
+	/// Appends additional parameter for specific calls.
+	fn augment_request(&self, request: &mut Request, meta: Option<Meta>) {
+		use jsonrpc_core::{Call, Params, to_value};
+
+		fn augment_call(call: &mut Call, meta: Option<&Meta>) {
+			match (call, meta) {
+				(&mut Call::MethodCall(ref mut method_call), Some(meta)) if &method_call.method == MIDDLEWARE_METHOD => {
+					let session = to_value(&meta.app_id);
+
+					let params = match method_call.params {
+						Some(Params::Array(ref vec)) if vec.len() == 0 => Some(Params::Array(vec![session])),
+						// invalid params otherwise
+						_ => None,
+					};
+
+					method_call.params = params;
+				},
+				_ => {}
+			}
+		}
+
+		match *request {
+			Request::Single(ref mut call) => augment_call(call, meta.as_ref()),
+			Request::Batch(ref mut vec) => {
+				for mut call in vec {
+					augment_call(call, meta.as_ref())
+				}
+			},
+		}
+	}
+}
+
+#[derive(Debug)]
+struct Meta {
+	app_id: String,
+}
+
+impl RpcHandler for RpcMiddleware {
+	type Metadata = Meta;
+
+	fn read_metadata(&self, request: &hyper::server::Request<hyper::net::HttpStream>) -> Option<Self::Metadata> {
+		let meta = request.headers().get::<hyper::header::Referer>()
+			.and_then(|referer| hyper::Url::parse(referer).ok())
+			.and_then(|url| {
+				url.path_segments()
+					.and_then(|mut split| split.next())
+					.map(|app_id| Meta {
+						app_id: app_id.to_owned(),
+					})
+			});
+		println!("{:?}, {:?}", meta, request.headers());
+		meta
+	}
+
+	fn handle_request<H>(&self, request_str: &str, response_handler: H, meta: Option<Self::Metadata>) where
+		H: ResponseHandler<Option<String>, Option<String>> + 'static
+	{
+		let handler = IoHandler::convert_handler(response_handler);
+		let request = IoHandler::read_request(request_str);
+		trace!(target: "rpc", "Request metadata: {:?}", meta);
+
+		match request {
+			Ok(mut request) => {
+				self.augment_request(&mut request, meta);
+				self.handler.request_handler().handle_request(request, handler, None)
+			},
+			Err(error) => handler.send(Some(Response::from(error))),
+		}
+	}
+}
+