Add an RPC request for the state of the network (#1884)

* Add an RPC request for the state of the network

* Fix concerns

* Fix tests

* Replace comment with TODO

* Rename the RPC

substrate/core/rpc/src/system/mod.rs

@@ -60,6 +60,13 @@ pub trait SystemApi<Hash, Number> {
 	/// Returns currently connected peers
 	#[rpc(name = "system_peers")]
 	fn system_peers(&self) -> Result<Vec<PeerInfo<Hash, Number>>>;
+
+	/// Returns current state of the network.
+	///
+	/// **Warning**: This API is not stable.
+	// TODO: make this stable and move structs https://github.com/paritytech/substrate/issues/1890
+	#[rpc(name = "system_networkState")]
+	fn system_network_state(&self) -> Result<network::NetworkState>;
 }
 
 /// System API implementation
@@ -120,4 +127,8 @@ impl<B: traits::Block> SystemApi<B::Hash, <B::Header as HeaderT>::Number> for Sy
 			best_number: p.best_number,
 		}).collect())
 	}
+
+	fn system_network_state(&self) -> Result<network::NetworkState> {
+		Ok(self.sync.network_state())
+	}
 }

substrate/core/rpc/src/system/tests.rs

@@ -52,6 +52,20 @@ impl network::SyncProvider<Block> for Status {
 		}
 	}
 
+	fn network_state(&self) -> network::NetworkState {
+		network::NetworkState {
+			peer_id: String::new(),
+			listened_addresses: Default::default(),
+			is_reserved_only: false,
+			reserved_peers: Default::default(),
+			banned_peers: Default::default(),
+			connected_peers: Default::default(),
+			not_connected_peers: Default::default(),
+			average_download_per_sec: 0,
+			average_upload_per_sec: 0,
+		}
+	}
+
 	fn peers(&self) -> Vec<(NodeIndex, NetworkPeerInfo<Block>)> {
 		vec![(1, NetworkPeerInfo {
 			peer_id: self.peer_id.clone(),
@@ -181,3 +195,21 @@ fn system_peers() {
 		}]
 	);
 }
+
+#[test]
+fn system_network_state() {
+	assert_eq!(
+		api(None).system_network_state().unwrap(),
+		network::NetworkState {
+			peer_id: String::new(),
+			listened_addresses: Default::default(),
+			is_reserved_only: false,
+			reserved_peers: Default::default(),
+			banned_peers: Default::default(),
+			connected_peers: Default::default(),
+			not_connected_peers: Default::default(),
+			average_download_per_sec: 0,
+			average_upload_per_sec: 0,
+		}
+	);
+}