Add noMeta query param to tx/artifacts (#222)

* Add noMeta query param to `tx/artifacts`

* Fix comment

* Change to boolean arg for service

Author: emostov

src/controllers/transaction/TransactionMaterialController.ts

@@ -13,6 +13,10 @@ import AbstractController from '../AbstractController';
  * - (Optional) `number`: Block hash or number at which to query. If not provided, queries
  *   finalized head.
  *
+ * Query
+ * - (Optional) `noMeta`: If true, does not return metadata hex. This is useful when metadata is not
+ * needed and response time is a concern. Defaults to false.
+ *
  * Returns:
  * - `at`: Block number and hash at which the call was made.
  * - `genesisHash`: The hash of the chain's genesis block.
@@ -56,14 +60,16 @@ export default class TransactionMaterialController extends AbstractController<
 	 * @param res Express Response
 	 */
 	private getTxArtifacts: RequestHandler = async (
-		_req,
+		{ query: { noMeta } },
 		res
 	): Promise<void> => {
 		const hash = await this.api.rpc.chain.getFinalizedHead();
 
+		const noMetaArg = noMeta === 'true' ? true : false;
+
 		TransactionMaterialController.sanitizedSend(
 			res,
-			await this.service.fetchTransactionMaterial(hash)
+			await this.service.fetchTransactionMaterial(hash, noMetaArg)
 		);
 	};
 
@@ -75,14 +81,16 @@ export default class TransactionMaterialController extends AbstractController<
 	 * @param res Express Response
 	 */
 	private getTxArtifactsAtBlock: RequestHandler<INumberParam> = async (
-		{ params: { number } },
+		{ params: { number }, query: { noMeta } },
 		res
 	): Promise<void> => {
 		const hash = await this.getHashForBlock(number);
 
+		const noMetaArg = noMeta === 'true' ? true : false;
+
 		TransactionMaterialController.sanitizedSend(
 			res,
-			await this.service.fetchTransactionMaterial(hash)
+			await this.service.fetchTransactionMaterial(hash, noMetaArg)
 		);
 	};
 }

src/services/transaction/TransactionMaterialService.spec.ts

@@ -11,7 +11,8 @@ describe('TransactionMaterialService', () => {
 			expect(
 				sanitizeNumbers(
 					await transactionMaterialService.fetchTransactionMaterial(
-						blockHash789629
+						blockHash789629,
+						false
 					)
 				)
 			).toStrictEqual(response789629);

src/services/transaction/TransactionMaterialService.ts

@@ -11,10 +11,34 @@ export class TransactionMaterialService extends AbstractService {
 	 * @param hash `BlockHash` to make call at
 	 */
 	async fetchTransactionMaterial(
-		hash: BlockHash
+		hash: BlockHash,
+		noMeta: boolean
 	): Promise<ITransactionMaterial> {
 		const api = await this.ensureMeta(hash);
 
+		if (noMeta) {
+			const [header, genesisHash, name, version] = await Promise.all([
+				api.rpc.chain.getHeader(hash),
+				api.rpc.chain.getBlockHash(0),
+				api.rpc.system.chain(),
+				api.rpc.state.getRuntimeVersion(hash),
+			]);
+
+			const at = {
+				hash,
+				height: header.number.toNumber().toString(10),
+			};
+
+			return {
+				at,
+				genesisHash,
+				chainName: name.toString(),
+				specName: version.specName.toString(),
+				specVersion: version.specVersion,
+				txVersion: version.transactionVersion,
+			};
+		}
+
 		const [
 			header,
 			metadata,

src/types/responses/TransactionMaterial.ts

@@ -10,5 +10,5 @@ export interface ITransactionMaterial {
 	specName: string;
 	specVersion: U32;
 	txVersion: U32;
-	metadata: string;
+	metadata?: string;
 }