feat: add getVersion method

web3.js/module.flow.js

@@ -69,6 +69,10 @@ declare module '@solana/web3.js' {
     accountInfo: AccountInfo,
   };
 
+  declare export type Version = {
+    'solana-core': string,
+  };
+
   declare export type VoteAccountInfo = {
     votePubkey: string,
     nodePubkey: string,
@@ -130,6 +134,7 @@ declare module '@solana/web3.js' {
     ): Promise<SignatureSuccess | TransactionError | null>;
     getTransactionCount(commitment: ?Commitment): Promise<number>;
     getTotalSupply(commitment: ?Commitment): Promise<number>;
+    getVersion(): Promise<Version>;
     getInflation(commitment: ?Commitment): Promise<Inflation>;
     getEpochSchedule(): Promise<EpochSchedule>;
     getRecentBlockhash(

web3.js/src/connection.js

@@ -132,6 +132,16 @@ const GetEpochScheduleResult = struct({
   first_normal_slot: 'number',
 });
 
+/**
+ * Version info for a node
+ *
+ * @typedef {Object} Version
+ * @property {string} solana-core Version of solana-core
+ */
+const Version = struct({
+  'solana-core': 'string',
+});
+
 function createRpcRequest(url): RpcRequest {
   const server = jayson(async (request, callback) => {
     const options = {
@@ -204,6 +214,16 @@ const GetBalanceRpcResult = struct({
   result: 'number?',
 });
 
+/**
+ * Expected JSON RPC response for the "getVersion" message
+ */
+const GetVersionRpcResult = struct({
+  jsonrpc: struct.literal('2.0'),
+  id: 'string',
+  error: 'any?',
+  result: Version,
+});
+
 /**
  * @private
  */
@@ -871,6 +891,19 @@ export class Connection {
     return res.result;
   }
 
+  /**
+   * Fetch the node version
+   */
+  async getVersion(): Promise<Version> {
+    const unsafeRes = await this._rpcRequest('getVersion', []);
+    const res = GetVersionRpcResult(unsafeRes);
+    if (res.error) {
+      throw new Error(res.error.message);
+    }
+    assert(typeof res.result !== 'undefined');
+    return res.result;
+  }
+
   /**
    * Request an allocation of lamports to the specified account
    */

web3.js/test/connection.test.js

@@ -475,6 +475,25 @@ test('get recent blockhash', async () => {
   expect(feeCalculator.lamportsPerSignature).toBeGreaterThanOrEqual(0);
 });
 
+test('getVersion', async () => {
+  const connection = new Connection(url);
+
+  mockRpc.push([
+    url,
+    {
+      method: 'getVersion',
+      params: [],
+    },
+    {
+      error: null,
+      result: {'solana-core': '0.20.4'},
+    },
+  ]);
+
+  const version = await connection.getVersion();
+  expect(version['solana-core']).toBeTruthy();
+});
+
 test('request airdrop', async () => {
   const account = new Account();
   const connection = new Connection(url, 'recent');