expose peer information via rpc (#1362)

* expose peer information via rpc

* fixes tests

* cleanup

Co-Authored-By: xlc <xlchen1291@gmail.com>

* Update docs

Co-Authored-By: xlc <xlchen1291@gmail.com>

* Add missing docs

* keep original type for PeerInfo best_hash/best_number

* cleanup

* Update mod.rs

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

@@ -16,8 +16,10 @@
 
 use super::*;
 
-use network::{self, SyncState, SyncStatus, ProtocolStatus};
+use network::{self, SyncState, SyncStatus, ProtocolStatus, NodeIndex, PeerId, PeerInfo as NetworkPeerInfo, PublicKey};
+use network::config::Roles;
 use test_client::runtime::Block;
+use primitives::H256;
 
 #[derive(Default)]
 struct Status {
@@ -37,6 +39,15 @@ impl network::SyncProvider<Block> for Status {
 			num_active_peers: 0,
 		}
 	}
+
+	fn peers(&self) -> Vec<(NodeIndex, Option<PeerId>, NetworkPeerInfo<Block>)> {
+		vec![(1, Some(PublicKey::Ed25519((0 .. 32).collect::<Vec<u8>>()).into()), NetworkPeerInfo {
+			roles: Roles::FULL,
+			protocol_version: 1,
+			best_hash: Default::default(),
+			best_number: 1
+		})]
+	}
 }
 
 
@@ -129,3 +140,18 @@ fn system_health() {
 		}
 	);
 }
+
+#[test]
+fn system_peers() {
+	assert_eq!(
+		api(None).system_peers().unwrap(),
+		vec![PeerInfo {
+			index: 1,
+			peer_id: "QmS5oyTmdjwBowwAH1D9YQnoe2HyWpVemH8qHiU5RqWPh4".into(),
+			roles: "FULL".into(),
+			protocol_version: 1,
+			best_hash: Default::default(),
+			best_number: 1u64,
+		}]
+	);
+}