v0.1.7 (#16)

* chore: Bump api to 1.5.1

* feat: Metadata endpoint

* feat: Update readme

README.md

@@ -20,6 +20,8 @@ yarn start
 + `/block/NUMBER` fetch block details at block height `NUMBER`.
 + `/balance/ADDRESS` fetch balances for `ADDRESS` at latest finalized block.
 + `/balance/ADDRESS/NUMBER` fetch balances for `ADDRESS` at block height `NUMBER`.
++ `/metadata` fetch chain metadata at latest finalized block.
++ `/metadata/NUMBER` fetch chain metadata at block height `NUMBER`.
 
 ### Configuration
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "polkadot-rpc-proxy",
-  "version": "0.1.6",
+  "version": "0.1.7",
   "description": "",
   "main": "index.js",
   "scripts": {
@@ -11,10 +11,10 @@
   "author": "",
   "license": "GPL-3.0-or-later",
   "dependencies": {
-    "@polkadot/api": "1.4.0-beta.45",
-    "@polkadot/metadata": "1.4.0-beta.45",
-    "@polkadot/rpc-provider": "1.4.0-beta.45",
-    "@polkadot/types": "1.4.0-beta.45",
+    "@polkadot/api": "1.5.1",
+    "@polkadot/metadata": "1.5.1",
+    "@polkadot/rpc-provider": "1.5.1",
+    "@polkadot/types": "1.5.1",
     "@types/express": "^4.17.2",
     "express": "^4.17.1",
     "typescript": "^3.8.2"

src/ApiHandler.ts

@@ -38,12 +38,10 @@ export default class ApiHandler {
 	}
 
 	async fetchBlock(hash: BlockHash) {
-		await this.ensureMeta(hash);
-
-		const { api } = this;
+		const api = await this.ensureMeta(hash);
 		const [{ block }, events] = await Promise.all([
 			api.rpc.chain.getBlock(hash),
-			this.fetchEvents(hash),
+			this.fetchEvents(api, hash),
 		]);
 
 		const { parentHash, number, stateRoot, extrinsicsRoot } = block.header;
@@ -126,9 +124,7 @@ export default class ApiHandler {
 	}
 
 	async fetchBalance(hash: BlockHash, address: string) {
-		await this.ensureMeta(hash);
-
-		const { api } = this;
+		const api = await this.ensureMeta(hash);
 
 		const [header, free, reserved, locks, nonce] = await Promise.all([
 			api.rpc.chain.getHeader(hash),
@@ -146,15 +142,23 @@ export default class ApiHandler {
 		return { at, nonce, free, reserved, locks };
 	}
 
-	async fetchEvents(hash: BlockHash): Promise<EventRecord[] | string> {
+	async fetchMetadata(hash: BlockHash) {
+		const api = await this.ensureMeta(hash);
+
+		const metadata = await api.rpc.state.getMetadata(hash);
+
+		return metadata;
+	}
+
+	async fetchEvents(api: ApiPromise, hash: BlockHash): Promise<EventRecord[] | string> {
 		try {
-			return await await this.api.query.system.events.at(hash);
+			return await await api.query.system.events.at(hash);
 		} catch (_) {
 			return 'Unable to fetch Events, cannot confirm extrinsic status. Check pruning settings on the node.';
 		}
 	}
 
-	async ensureMeta(hash: BlockHash) {
+	async ensureMeta(hash: BlockHash): Promise<ApiPromise> {
 		const { api } = this;
 
 		try {
@@ -167,13 +171,15 @@ export default class ApiHandler {
 				const meta = await api.rpc.state.getMetadata(hash);
 				const chain = await api.rpc.system.chain();
 
-				api.registry.register(getSpecTypes(chain, runtimeVersion));
+				api.registry.register(getSpecTypes(api.registry, chain, runtimeVersion));
 				api.registry.setMetadata(meta);
 			}
 		} catch (err) {
 			console.error(`Failed to get Metadata for block ${hash}, using latest.`);
 			console.error(err);
 			this.specVersion = api.createType('u32', -1);
 		}
+
+		return api;
 	}
 }

src/main.ts

@@ -27,6 +27,20 @@ const WS_URL = process.env.NODE_WS_URL || 'ws://127.0.0.1:9944';
 
 type Params = { [key: string]: string };
 
+interface Error {
+	error: string;
+}
+
+function parseNumber(n: string): [Error | null, number] {
+	const num = Number(n);
+
+	if (!Number.isInteger(num)) {
+		return [{ error: 'Invalid block number' }, 0];
+	}
+
+	return [null, num];
+}
+
 async function main() {
 	const api = await ApiPromise.create({ provider: new WsProvider(WS_URL) });
 	const handler = new ApiHandler(api);
@@ -47,7 +61,12 @@ async function main() {
 	get('/', async (req) => 'Sidecar is running, go to /block to get latest finalized block');
 
 	get('/block/:number', async (params) => {
-		const number = Number(params.number) || 0;
+		const [error, number] = parseNumber(params.number);
+
+		if (error) {
+			return error;
+		}
+
 		const hash = await api.rpc.chain.getBlockHash(number);
 
 		return await handler.fetchBlock(hash);
@@ -68,12 +87,35 @@ async function main() {
 
 	get('/balance/:address/:number', async (params) => {
 		const { address } = params;
-		const number = Number(params.number) || 0;
+		const [error, number] = parseNumber(params.number);
+
+		if (error) {
+			return error;
+		}
+
 		const hash = await api.rpc.chain.getBlockHash(number);
 
 		return await handler.fetchBalance(hash, address);
 	});
 
+	get('/metadata/', async () => {
+		const hash = await api.rpc.chain.getFinalizedHead();
+
+		return await handler.fetchMetadata(hash);
+	});
+
+	get('/metadata/:number', async (params) => {
+		const [error, number] = parseNumber(params.number);
+
+		if (error) {
+			return error;
+		}
+
+		const hash = await api.rpc.chain.getBlockHash(number);
+
+		return await handler.fetchMetadata(hash);
+	});
+
 	app.listen(PORT, HOST, () => console.log(`Running on http://${HOST}:${PORT}/`))
 }