Add system_peers RPC endpoint (#577)

* Add system_peers RPC endpoint

* Don't double-up on error logs

packages/api/src/promise/index.ts

@@ -209,8 +209,6 @@ export default class ApiPromise extends ApiBase<DecoratedRpc, QueryableStorage,
           .pipe(
             // if we find an error (invalid params, etc), reject the promise
             catchError((error) => {
-              console.error(error);
-
               if (!isCompleted) {
                 isCompleted = true;
 

packages/type-jsonrpc/src/system.ts

@@ -38,6 +38,13 @@ const health: RpcMethodOpt = {
   type: 'Health'
 };
 
+const peers: RpcMethodOpt = {
+  description: 'Returns the currently connected peers',
+  params: [],
+  // @ts-ignore the Vec<> wrap is fine
+  type: 'Vec<PeerInfo>'
+};
+
 const section = 'system';
 
 /**
@@ -52,6 +59,7 @@ export default {
     chain: createMethod(section, 'chain', chain),
     health: createMethod(section, 'health', health),
     name: createMethod(section, 'name', name),
+    peers: createMethod(section, 'peers', peers),
     properties: createMethod(section, 'properties', properties),
     version: createMethod(section, 'version', version)
   }

packages/types/src/Health.ts

@@ -4,16 +4,21 @@
 
 import Struct from './codec/Struct';
 import Bool from './Bool';
-import U32 from './U32';
+import USize from './USize';
 
 const JSON_MAP = new Map([
   ['isSyncing', 'is_syncing']
 ]);
 
+/**
+ * @name Health
+ * @description
+ * A system health indicator, reported back over RPC
+ */
 export default class Health extends Struct {
   constructor (value?: any) {
     super({
-      peers: U32,
+      peers: USize,
       isSyncing: Bool
     }, value, JSON_MAP);
   }
@@ -28,7 +33,7 @@ export default class Health extends Struct {
   /**
    * @description The numbers of peers as [[U32]]
    */
-  get peers (): U32 {
-    return this.get('peers') as U32;
+  get peers (): USize {
+    return this.get('peers') as USize;
   }
 }

packages/types/src/PeerInfo.ts

@@ -0,0 +1,76 @@
+// Copyright 2017-2019 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import Struct from './codec/Struct';
+import BlockNumber from './BlockNumber';
+import Hash from './Hash';
+import Text from './Text';
+import U32 from './U32';
+import USize from './USize';
+
+const JSON_MAP = new Map([
+  ['bestHash', 'best_hash'],
+  ['bestNumber', 'best_number'],
+  ['protocolVersion', 'protocol_version']
+]);
+
+/**
+ * @name PeerInfo
+ * @description
+ * A system peer info indicator, reported back over RPC
+ */
+export default class PeerInfo extends Struct {
+  constructor (value?: any) {
+    super({
+      index: USize,
+      peerId: Text,
+      roles: Text,
+      protocolVersion: U32,
+      bestHash: Hash,
+      bestNumber: BlockNumber
+    }, value, JSON_MAP);
+  }
+
+  /**
+   * @description The best block hash for the peer
+   */
+  get bestHash (): Hash {
+    return this.get('bestHash') as Hash;
+  }
+
+  /**
+   * @description The best block hash for the peer
+   */
+  get bestNumber (): BlockNumber {
+    return this.get('bestNumber') as BlockNumber;
+  }
+
+  /**
+   * @description The index of the peer in our list
+   */
+  get index (): USize {
+    return this.get('index') as USize;
+  }
+
+  /**
+   * @description The p2p network id for the peer
+   */
+  get peerId (): Text {
+    return this.get('peerId') as Text;
+  }
+
+  /**
+   * @description The index of the peer in our list
+   */
+  get protocolVersion (): U32 {
+    return this.get('protocolVersion') as U32;
+  }
+
+  /**
+   * @description The roles of the peer on the network
+   */
+  get roles (): Text {
+    return this.get('roles') as Text;
+  }
+}

packages/types/src/USize.ts

@@ -0,0 +1,14 @@
+// Copyright 2017-2019 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import U64 from './U64';
+
+/**
+ * @name USize
+ * @description
+ * A System default unsigned number, typically used in RPC to report non-consensus
+ * data. It is a wrapper for [[U64]] as a 64-binary default
+ */
+export default class USize extends U64 {
+}

packages/types/src/index.ts

@@ -64,6 +64,7 @@ export { default as IndexCompact } from './NonceCompact';
 export { default as Justification } from './Justification';
 export { default as Origin } from './Origin';
 export { default as ParaId } from './ParaId';
+export { default as PeerInfo } from './PeerInfo';
 export { default as PendingExtrinsics } from './PendingExtrinsics';
 export { default as Permill } from './Permill';
 export { default as Perbill } from './Perbill';
@@ -89,6 +90,7 @@ export { default as u32 } from './U32';
 export { default as u64 } from './U64';
 export { default as u128 } from './U128';
 export { default as u256 } from './U256';
+export { default as usize } from './USize';
 export { default as ValidatorPrefs } from './ValidatorPrefs';
 export { default as Vote } from './Vote';
 export { default as VoteThreshold } from './VoteThreshold';