Supporting /api/ping for dapps server (#1543)

* Refactoring dapps to support API endpoints.

* Using ContentHandler for unauthorized requests

* Extracting url stuff

* Adding ping endpoint

* CORS support for ping request

* Fixing url.is_none()

* minor formatting fix

[ci:skip]

dapps/src/api/api.rs

@@ -15,20 +15,23 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 use std::sync::Arc;
-use endpoint::{Endpoint, Endpoints, Handler, EndpointPath};
-use api::types::{App, ApiError};
-use api::response::{as_json, as_json_error};
 use hyper::{server, net, Decoder, Encoder, Next};
+use api::types::{App, ApiError};
+use api::response::{as_json, as_json_error, ping_response};
+use handlers::extract_url;
+use endpoint::{Endpoint, Endpoints, Handler, EndpointPath};
 
 #[derive(Clone)]
 pub struct RestApi {
+	local_domain: String,
 	endpoints: Arc<Endpoints>,
 }
 
 impl RestApi {
-	pub fn new(endpoints: Arc<Endpoints>) -> Box<Endpoint> {
+	pub fn new(local_domain: String, endpoints: Arc<Endpoints>) -> Box<Endpoint> {
 		Box::new(RestApi {
-			endpoints: endpoints
+			local_domain: local_domain,
+			endpoints: endpoints,
 		})
 	}
 
@@ -59,9 +62,28 @@ struct RestApiRouter {
 
 impl server::Handler<net::HttpStream> for RestApiRouter {
 
-	fn on_request(&mut self, _request: server::Request<net::HttpStream>) -> Next {
-		self.handler = as_json(&self.api.list_apps());
-		Next::write()
+	fn on_request(&mut self, request: server::Request<net::HttpStream>) -> Next {
+		let url = extract_url(&request);
+		if url.is_none() {
+			// Just return 404 if we can't parse URL
+			return Next::write();
+		}
+
+		let url = url.expect("Check for None is above; qed");
+		let endpoint = url.path.get(1).map(|v| v.as_str());
+
+		let handler = endpoint.and_then(|v| match v {
+			"apps" => Some(as_json(&self.api.list_apps())),
+			"ping" => Some(ping_response(&self.api.local_domain)),
+			_ => None,
+		});
+
+		// Overwrite default
+		if let Some(h) = handler {
+			self.handler = h;
+		}
+
+		self.handler.on_request(request)
 	}
 
 	fn on_request_readable(&mut self, decoder: &mut Decoder<net::HttpStream>) -> Next {

dapps/src/api/response.rs

@@ -17,7 +17,7 @@
 use serde::Serialize;
 use serde_json;
 use endpoint::Handler;
-use handlers::ContentHandler;
+use handlers::{ContentHandler, EchoHandler};
 
 pub fn as_json<T : Serialize>(val: &T) -> Box<Handler> {
 	Box::new(ContentHandler::ok(serde_json::to_string(val).unwrap(), "application/json".to_owned()))
@@ -26,3 +26,11 @@ pub fn as_json<T : Serialize>(val: &T) -> Box<Handler> {
 pub fn as_json_error<T : Serialize>(val: &T) -> Box<Handler> {
 	Box::new(ContentHandler::not_found(serde_json::to_string(val).unwrap(), "application/json".to_owned()))
 }
+
+pub fn ping_response(local_domain: &str) -> Box<Handler> {
+	Box::new(EchoHandler::cors(vec![
+		format!("http://{}", local_domain),
+		// Allow CORS calls also for localhost
+		format!("http://{}", local_domain.replace("127.0.0.1", "localhost")),
+	]))
+}

dapps/src/api/types.rs

@@ -19,5 +19,3 @@ include!("types.rs.in");
 
 #[cfg(not(feature = "serde_macros"))]
 include!(concat!(env!("OUT_DIR"), "/types.rs"));
-
-

dapps/src/api/types.rs.in

@@ -48,4 +48,3 @@ pub struct ApiError {
 	pub detail: String,
 }
 
-