feat: add at query param for staking-payouts (#1388)

* feat: add `at` query param for staking-payouts

* add docs

* rewrite derive to fit historic data

* hack for tests

* add new mock data

* export mock data

* add single new test

* fix test

* update test to reflect validator and nominator

* add extract axposure test

* extractExposure for nom and val

* extractTotalValidatorRewardPoints

* error test

* another error test

* deriveNominatedExposures

* replace original file

* finalize tests

docs/src/openapi-v1.yaml

@@ -472,6 +472,15 @@ paths:
         schema:
           format: SS58
           type: string
+      - name: at
+        in: query
+        description: Block at which to query staking payouts.
+        required: false
+        schema:
+          type: string
+          description: Block height (as a non-negative integer) or hash
+            (as a hex string).
+          format: unsignedInteger or $hex
       - name: depth
         in: query
         description: The number of eras to query for payouts of. Must be less

src/controllers/accounts/AccountsStakingPayoutsController.ts

@@ -14,7 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import { ApiPromise } from '@polkadot/api';
+import type { ApiPromise } from '@polkadot/api';
+import type { ApiDecoration } from '@polkadot/api/types';
 import { Option } from '@polkadot/types';
 import BN from 'bn.js';
 import { RequestHandler } from 'express';
@@ -95,10 +96,12 @@ export default class AccountsStakingPayoutsController extends AbstractController
 	 * @param res Express Response
 	 */
 	private getStakingPayoutsByAccountId: RequestHandler<IAddressParam> = async (
-		{ params: { address }, query: { depth, era, unclaimedOnly } },
+		{ params: { address }, query: { depth, era, unclaimedOnly, at } },
 		res,
 	): Promise<void> => {
-		const { hash, eraArg, currentEra } = await this.getEraAndHash(this.verifyAndCastOr('era', era, undefined));
+		const hash = await this.getHashFromAt(at);
+		const apiAt = await this.api.at(hash);
+		const { eraArg, currentEra } = await this.getEraAndHash(apiAt, this.verifyAndCastOr('era', era, undefined));
 
 		const unclaimedOnlyArg = unclaimedOnly === 'false' ? false : true;
 
@@ -111,15 +114,15 @@ export default class AccountsStakingPayoutsController extends AbstractController
 				eraArg,
 				unclaimedOnlyArg,
 				currentEra,
+				apiAt,
 			),
 		);
 	};
 
-	private async getEraAndHash(era?: number) {
-		const [hash, activeEraOption, currentEraMaybeOption] = await Promise.all([
-			this.api.rpc.chain.getFinalizedHead(),
-			this.api.query.staking.activeEra(),
-			this.api.query.staking.currentEra(),
+	private async getEraAndHash(apiAt: ApiDecoration<'promise'>, era?: number) {
+		const [activeEraOption, currentEraMaybeOption] = await Promise.all([
+			apiAt.query.staking.activeEra(),
+			apiAt.query.staking.currentEra(),
 		]);
 
 		if (activeEraOption.isNone) {
@@ -148,7 +151,6 @@ export default class AccountsStakingPayoutsController extends AbstractController
 		}
 
 		return {
-			hash,
 			eraArg: era === undefined ? activeEra - 1 : era,
 			currentEra,
 		};