Add RPC enode lookup (#3096)

* add enode rpc

* spaces -> tabs

rpc/src/v1/helpers/errors.rs

@@ -41,6 +41,7 @@ mod codes {
 	pub const ACCOUNT_ERROR: i64 = -32023;
 	pub const SIGNER_DISABLED: i64 = -32030;
 	pub const DAPPS_DISABLED: i64 = -32031;
+	pub const NETWORK_DISABLED: i64 = -32035;
 	pub const REQUEST_REJECTED: i64 = -32040;
 	pub const REQUEST_REJECTED_LIMIT: i64 = -32041;
 	pub const REQUEST_NOT_FOUND: i64 = -32042;
@@ -185,6 +186,14 @@ pub fn dapps_disabled() -> Error {
 	}
 }
 
+pub fn network_disabled() -> Error {
+	Error {
+		code: ErrorCode::ServerError(codes::NETWORK_DISABLED),
+		message: "Network is disabled or not yet up.".into(),
+		data: None
+	}
+}
+
 pub fn encryption_error<T: fmt::Debug>(error: T) -> Error {
 	Error {
 		code: ErrorCode::ServerError(codes::ENCRYPTION_ERROR),

rpc/src/v1/impls/ethcore.rs

@@ -353,4 +353,8 @@ impl<C, M, S: ?Sized, F> Ethcore for EthcoreClient<C, M, S, F> where
 			Mode::Active => "active",
 		}.into())
 	}
+
+	fn enode(&self) -> Result<String, Error> {
+		take_weak!(self.sync).enode().ok_or_else(errors::network_disabled)
+	}
 }

rpc/src/v1/tests/helpers/sync_provider.rs

@@ -93,5 +93,9 @@ impl SyncProvider for TestSyncProvider {
 			}
 		]
 	}
+
+	fn enode(&self) -> Option<String> {
+		None
+	}
 }
 

rpc/src/v1/traits/ethcore.rs

@@ -133,5 +133,9 @@ build_rpc_trait! {
 		/// Get the mode. Results one of: "active", "passive", "dark", "off".
 		#[rpc(name = "ethcore_mode")]
 		fn mode(&self) -> Result<String, Error>;
+
+		/// Get the enode of this node.
+		#[rpc(name = "ethcore_enode")]
+		fn enode(&self) -> Result<String, Error>;
 	}
 }

sync/src/api.rs

@@ -73,6 +73,9 @@ pub trait SyncProvider: Send + Sync {
 
 	/// Get peers information
 	fn peers(&self) -> Vec<PeerInfo>;
+    
+	/// Get the enode if available.
+	fn enode(&self) -> Option<String>;
 }
 
 /// Peer connection information
@@ -143,6 +146,10 @@ impl SyncProvider for EthSync {
 			self.handler.sync.write().peers(&sync_io)
 		}).unwrap_or(Vec::new())
 	}
+
+	fn enode(&self) -> Option<String> {
+		self.network.external_url()
+	}
 }
 
 struct SyncProtocolHandler {