Implement /runtime/metadata

README.md

@@ -84,8 +84,6 @@ a 32-byte hex string (`0x` followed by 64 hexadecimal digits) that denotes the b
 
 -   [`/block` fetch latest finalized block details.](/src/controllers/blocks/BlocksController.ts)
 
--   [`/block` fetch latest finalized block details.](/src/controllers/blocks/BlocksController.ts)
-
 -   [`/block/NUMBER` fetch block details at the block identified by 'NUMBER`.](/src/controllers/blocks/BlocksController.ts)
 
 -   [`/balance/ADDRESS` fetch balances for `ADDRESS` at latest finalized block.](src/controllers/accounts/AccountsBalanceInfoController.ts)
@@ -104,16 +102,14 @@ a 32-byte hex string (`0x` followed by 64 hexadecimal digits) that denotes the b
 
 -   [`/vesting/ADDRESS/NUMBER` fetch the vesting info for `ADDRESS` at the block identified by 'NUMBER`.](src/controllers/accounts/AccountsVestingInfoController.ts)
 
--   [`/metadata` fetch chain metadata at latest finalized block.](src/controllers/runtime/RuntimeMetadataController.ts)
-
--   [`/metadata/NUMBER` fetch chain metadata at the block identified by 'NUMBER`.](src/controllers/runtime/RuntimeMetadataController.ts)
-
 -   [`/node/network` fetch information about the Substrate node's activity in the peer-to-peer network.](src/controllers/node/NodeNetworkController.ts)
 
 -   [`/node/transaction-pool` fetch pending extrinsics from the Substrate node.](src/controllers/node/NodeTransactionPoolController.ts)
 
 -   [`/node/version` fetch information about the Substrates node's implementation and versioning.](src/controllers/node/NodeVersionController.ts)
 
+-   [`/runtime/metadata` fetch the runtime metadata in decoded, JSON form.](src/controllers/runtime/RuntimeMetadataController.ts) (replaces `/metadata`)
+
 -   [`/runtime/code` fetch the Wasm code blob of the Substrate runtime.](src/controllers/runtime/RuntimeCodeController.ts)
 
 -   [`/runtime/spec` version information of the Substrate runtime.](src/controllers/runtime/RuntimeSpecController.ts)

openapi/openapi-proposal.yaml

@@ -944,7 +944,11 @@ paths:
       tags:
       - runtime
       summary: Get the runtime metadata in decoded, JSON form.
-      description: Returns the runtime metadata as a JSON object.
+      description: >-
+       Returns the runtime metadata as a JSON object.
+       Substrate Reference:
+       - FRAME Support: https://crates.parity.io/frame_support/metadata/index.html
+       - Knowledge Base: https://substrate.dev/docs/en/knowledgebase/runtime/metadata
       parameters:
       - name: at
         in: query

src/controllers/runtime/RuntimeMetadataController.ts

@@ -0,0 +1,50 @@
+import { ApiPromise } from '@polkadot/api';
+import { RequestHandler } from 'express';
+
+import { RuntimeMetadataService } from '../../services';
+import AbstractController from '../AbstractController';
+
+/**
+ * GET the chain's metadata.
+ *
+ * Query:
+ * - (Optional) `at`: Block hash or height at which to query. If not provided, queries
+ *   finalized head.
+ *
+ * Returns:
+ * - Metadata object.
+ *
+ * Substrate Reference:
+ * - FRAME Support: https://crates.parity.io/frame_support/metadata/index.html
+ * - Knowledge Base: https://substrate.dev/docs/en/knowledgebase/runtime/metadata
+ */
+export default class RuntimeMetadataController extends AbstractController<
+	RuntimeMetadataService
+> {
+	constructor(api: ApiPromise) {
+		super(api, '/runtime/metadata', new RuntimeMetadataService(api));
+		this.initRoutes();
+	}
+
+	protected initRoutes(): void {
+		this.safeMountAsyncGetHandlers([['', this.getMetadata]]);
+	}
+
+	/**
+	 * Get the chain's latest metadata in a decoded, JSON format.
+	 *
+	 * @param _req Express Request
+	 * @param res Express Response
+	 */
+	private getMetadata: RequestHandler = async (
+		{ query: { at } },
+		res
+	): Promise<void> => {
+		const hash = await this.getHashFromAt(at);
+
+		RuntimeMetadataController.sanitizedSend(
+			res,
+			await this.service.fetchMetadata(hash)
+		);
+	};
+}

src/controllers/runtime/index.ts

@@ -1,2 +1,3 @@
 export { default as RuntimeCode } from './RuntimeCodeController';
 export { default as RuntimeSpec } from './RuntimeSpecController';
+export { default as RuntimeMetadata } from './RuntimeMetadataController';

src/main.ts

@@ -97,6 +97,7 @@ async function main() {
 	);
 	const runtimeCodeController = new controllers.RuntimeCode(api);
 	const runtimeSpecController = new controllers.RuntimeSpec(api);
+	const runtimeMetadataController = new controllers.RuntimeMetadata(api);
 	const transactionDryRunController = new controllers.TransactionDryRun(api);
 
 	// Create our App
@@ -109,6 +110,7 @@ async function main() {
 			nodeTransactionPoolController,
 			runtimeCodeController,
 			runtimeSpecController,
+			runtimeMetadataController,
 			transactionDryRunController,
 			...v0Controllers,
 		],

src/services/runtime/RuntimeMetadataService.spec.ts

@@ -0,0 +1,18 @@
+import { sanitizeNumbers } from '../../sanitize/sanitizeNumbers';
+import { blockHash789629, mockApi } from '../test-helpers/mock';
+import * as response789629 from '../test-helpers/responses/runtime/metadata789629.json';
+import { RuntimeMetadataService } from './RuntimeMetadataService';
+
+const runtimeMetadataService = new RuntimeMetadataService(mockApi);
+
+describe('RuntimeMetadataService', () => {
+	describe('fetchMetadata', () => {
+		it('works when ApiPromise works (block 789629)', async () => {
+			expect(
+				sanitizeNumbers(
+					await runtimeMetadataService.fetchMetadata(blockHash789629)
+				)
+			).toStrictEqual(response789629);
+		});
+	});
+});

src/services/runtime/RuntimeMetadataService.ts

@@ -0,0 +1,19 @@
+import { Metadata } from '@polkadot/types';
+import { BlockHash } from '@polkadot/types/interfaces';
+
+import { AbstractService } from '../AbstractService';
+
+export class RuntimeMetadataService extends AbstractService {
+	/**
+	 * Fetch `Metadata` in decoded JSON form.
+	 *
+	 * @param hash `BlockHash` to make call at
+	 */
+	async fetchMetadata(hash: BlockHash): Promise<Metadata> {
+		const api = await this.ensureMeta(hash);
+
+		const metadata = await api.rpc.state.getMetadata(hash);
+
+		return metadata;
+	}
+}

src/services/runtime/index.ts

@@ -1,2 +1,3 @@
 export * from './RuntimeCodeService';
 export * from './RuntimeSpecService';
+export * from './RuntimeMetadataService';