feat: add decoded xcm data in blocks endpoint

src/controllers/blocks/BlocksController.ts

@@ -159,7 +159,7 @@ export default class BlocksController extends AbstractController<BlocksService>
 	 * @param res Express Response
 	 */
 	private getBlockById: RequestHandler<INumberParam> = async (
-		{ params: { number }, query: { eventDocs, extrinsicDocs, finalizedKey } },
+		{ params: { number }, query: { eventDocs, extrinsicDocs, finalizedKey, decodedXcmMsgs, paraId } },
 		res,
 	): Promise<void> => {
 		const checkFinalized = isHex(number);
@@ -168,6 +168,7 @@ export default class BlocksController extends AbstractController<BlocksService>
 
 		const eventDocsArg = eventDocs === 'true';
 		const extrinsicDocsArg = extrinsicDocs === 'true';
+		const decodedXcmMsgsArg = decodedXcmMsgs === 'true';
 		const finalizeOverride = finalizedKey === 'false';
 
 		const queryFinalizedHead = !this.options.finalizes ? false : true;
@@ -189,7 +190,10 @@ export default class BlocksController extends AbstractController<BlocksService>
 		const historicApi = await this.api.at(hash);
 
 		// We set the last param to true because we haven't queried the finalizedHead
-		BlocksController.sanitizedSend(res, await this.service.fetchBlock(hash, historicApi, options));
+		BlocksController.sanitizedSend(
+			res,
+			await this.service.fetchBlock(hash, historicApi, options, decodedXcmMsgsArg, paraId as string),
+		);
 	};
 
 	/**

src/services/blocks/BlocksService.ts

@@ -1,4 +1,4 @@
-// Copyright 2017-2022 Parity Technologies (UK) Ltd.
+// Copyright 2017-2023 Parity Technologies (UK) Ltd.
 // This file is part of Substrate API Sidecar.
 //
 // Substrate API Sidecar is free software: you can redistribute it and/or modify
@@ -56,6 +56,7 @@ import {
 import { IOption } from '../../types/util';
 import { isPaysFee } from '../../types/util';
 import { AbstractService } from '../AbstractService';
+import { XcmDecoder } from './XCMDecoder';
 
 /**
  * Types for fetchBlock's options
@@ -102,6 +103,8 @@ export class BlocksService extends AbstractService {
 		hash: BlockHash,
 		historicApi: ApiDecoration<'promise'>,
 		{ eventDocs, extrinsicDocs, checkFinalized, queryFinalizedHead, omitFinalizedTag }: FetchBlockOptions,
+		decodedXcmMsgsArg?: boolean,
+		paraId?: string,
 	): Promise<IBlock> {
 		const { api } = this;
 
@@ -287,7 +290,8 @@ export class BlocksService extends AbstractService {
 				kind: dispatchFeeType,
 			};
 		}
-
+		const decodedMsgs = decodedXcmMsgsArg ? new XcmDecoder(api, specName.toString(), extrinsics, paraId) : undefined;
+		const decodedXcmMsgs = decodedMsgs?.messages;
 		const response = {
 			number,
 			hash,
@@ -300,6 +304,7 @@ export class BlocksService extends AbstractService {
 			extrinsics,
 			onFinalize,
 			finalized,
+			decodedXcmMsgs,
 		};
 
 		// Store the block in the cache

src/services/blocks/XCMDecoder.ts

@@ -0,0 +1,151 @@
+// Copyright 2017-2023 Parity Technologies (UK) Ltd.
+// This file is part of Substrate API Sidecar.
+//
+// Substrate API Sidecar is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// 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 '@polkadot/api-augment';
+
+import { ApiPromise } from '@polkadot/api';
+import { Bytes } from '@polkadot/types';
+
+import {
+	IDownwardMessage,
+	IExtrinsic,
+	IFrameMethod,
+	IHorizontalMessage,
+	IMessages,
+	IUpwardMessage,
+} from '../../types/responses';
+
+enum ChainType {
+	Relay = 'Relay',
+	Parachain = 'Parachain',
+}
+
+export class XcmDecoder {
+	readonly messages: IMessages[];
+	readonly api: ApiPromise;
+	static curChainType: ChainType;
+
+	constructor(api: ApiPromise, specName: string, extrinsics: IExtrinsic[], paraId?: string) {
+		this.api = api;
+		XcmDecoder.curChainType = XcmDecoder.getCurChainType(specName);
+		this.messages = XcmDecoder.getMessages(api, extrinsics, paraId);
+	}
+
+	static getCurChainType(specName: string): ChainType {
+		const relay = ['polkadot', 'kusama', 'westend', 'rococo'];
+		if (relay.includes(specName)) {
+			return ChainType.Relay;
+		} else {
+			return ChainType.Parachain;
+		}
+	}
+
+	static getMessages(api: ApiPromise, extrinsics: IExtrinsic[], paraId?: string): IMessages[] {
+		const xcmMessages: IMessages[] = [];
+		if (XcmDecoder.curChainType === ChainType.Relay) {
+			extrinsics.forEach((extrinsic) => {
+				const frame = extrinsic.method as IFrameMethod;
+				if (frame.pallet === 'paraInherent' && frame.method === 'enter') {
+					const data: any = extrinsic.args.data;
+					const upwardMessage: IUpwardMessage[] = [];
+					if (paraId !== undefined) {
+						data.backedCandidates.forEach((candidate: any) => {
+							if (candidate.candidate.descriptor.paraId.toString() === paraId) {
+								const msg_decoded = XcmDecoder.checkUpwardMsg(api, candidate);
+								if (msg_decoded != undefined && Object.keys(msg_decoded).length > 0) {
+									upwardMessage.push(msg_decoded);
+								}
+							}
+						});
+					} else {
+						data.backedCandidates.forEach((candidate: any) => {
+							const msg_decoded = XcmDecoder.checkUpwardMsg(api, candidate);
+							if (msg_decoded != undefined && Object.keys(msg_decoded).length > 0) {
+								upwardMessage.push(msg_decoded);
+							}
+						});
+					}
+					xcmMessages.push({
+						upwardMessages: upwardMessage,
+					});
+				}
+			});
+		} else if (XcmDecoder.curChainType === ChainType.Parachain) {
+			extrinsics.forEach((extrinsic) => {
+				const frame: IFrameMethod = extrinsic.method as IFrameMethod;
+				if (frame.pallet === 'parachainSystem' && frame.method === 'setValidationData') {
+					const data: any = extrinsic.args.data;
+					data.downwardMessages.forEach((msg: any) => {
+						if (msg.msg.length > 0) {
+							const downwardMessage: IDownwardMessage[] = [];
+							const xcmMessageDecoded = this.decodeMsg(api, msg.msg);
+							downwardMessage.push({
+								sentAt: msg.sentAt,
+								data: xcmMessageDecoded,
+							});
+							xcmMessages.push({
+								downwardMessages: downwardMessage,
+							});
+						}
+					});
+					data.horizontalMessages.forEach((msg: [], index: string) => {
+						msg.forEach((msg: any) => {
+							const horizontalMessage: IHorizontalMessage[] = [];
+							const xcmMessageDecoded = this.decodeMsg(api, msg.data.slice(1));
+							horizontalMessage.push({
+								sentAt: msg.sentAt,
+								paraId: index,
+								data: xcmMessageDecoded,
+							});
+							xcmMessages.push({
+								horizontalMessages: horizontalMessage,
+							});
+						});
+					});
+				}
+			});
+		}
+		return xcmMessages;
+	}
+
+	static checkUpwardMsg(api: ApiPromise, candidate: any): IUpwardMessage | undefined {
+		if (candidate.candidate.commitments.upwardMessages.length > 0) {
+			const xcmMessage: string = candidate.candidate.commitments.upwardMessages;
+			const paraId: string = candidate.candidate.descriptor.paraId.toString();
+			const xcmMessageDecoded: string = this.decodeMsg(api, xcmMessage[0]);
+			const upwardMessage = {
+				paraId: paraId,
+				data: xcmMessageDecoded[0],
+			};
+			return upwardMessage;
+		} else {
+			return undefined;
+		}
+	}
+
+	static decodeMsg(api: ApiPromise, message: string): string {
+		const instructions = [];
+		let xcmMessage: string = message;
+		let instructionLength = 0;
+		while (xcmMessage.length != 0) {
+			const xcmInstructions: Bytes = api.createType('XcmVersionedXcm', xcmMessage);
+			instructions.push(xcmInstructions);
+			instructionLength = xcmInstructions.toU8a().length;
+			xcmMessage = xcmMessage.slice(instructionLength);
+		}
+		return instructions as unknown as string;
+	}
+}

src/types/responses/Block.ts

@@ -20,6 +20,7 @@ import { AccountId } from '@polkadot/types/interfaces/runtime';
 import { Codec } from '@polkadot/types/types';
 
 import { IExtrinsic, ISanitizedEvent } from '.';
+import { IMessages } from './BlockXCMMessages';
 
 export interface IBlock {
 	number: Compact<BlockNumber>;
@@ -33,6 +34,7 @@ export interface IBlock {
 	extrinsics: IExtrinsic[];
 	onFinalize: IOnInitializeOrFinalize;
 	finalized: boolean | undefined;
+	decodedXcmMsgs?: IMessages[] | undefined;
 }
 
 interface IOnInitializeOrFinalize {

src/types/responses/BlockXCMMessages.ts

@@ -0,0 +1,37 @@
+// Copyright 2017-2023 Parity Technologies (UK) Ltd.
+// This file is part of Substrate API Sidecar.
+//
+// Substrate API Sidecar is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+export interface IUpwardMessage {
+	paraId: string;
+	data: string;
+}
+
+export interface IDownwardMessage {
+	sentAt: string;
+	data: string;
+}
+
+export interface IHorizontalMessage {
+	sentAt: string;
+	paraId: string;
+	data: string;
+}
+
+export interface IMessages {
+	horizontalMessages?: IHorizontalMessage[];
+	downwardMessages?: IDownwardMessage[];
+	upwardMessages?: IUpwardMessage[];
+}

src/types/responses/index.ts

@@ -25,6 +25,7 @@ export * from './Assets';
 export * from './At';
 export * from './Block';
 export * from './BlockRaw';
+export * from './BlockXCMMessages';
 export * from './EraPayouts';
 export * from './Extrinsic';
 export * from './ForeignAssets';