chore: add OHLCVService for real-time candlestick WebSocket streaming

eslint-suppressions.json

@@ -862,34 +862,45 @@
       "count": 1
     }
   },
-  "packages/core-backend/src/AccountActivityService.test.ts": {
+  "packages/core-backend/src/api/shared-types.ts": {
     "no-restricted-syntax": {
-      "count": 2
+      "count": 1
     }
   },
-  "packages/core-backend/src/AccountActivityService.ts": {
+  "packages/core-backend/src/index.ts": {
     "no-restricted-syntax": {
-      "count": 1
+      "count": 4
     }
   },
-  "packages/core-backend/src/BackendWebSocketService.test.ts": {
+  "packages/core-backend/src/ws/AccountActivityService.test.ts": {
     "no-restricted-syntax": {
-      "count": 1
+      "count": 2
     }
   },
-  "packages/core-backend/src/BackendWebSocketService.ts": {
+  "packages/core-backend/src/ws/AccountActivityService.ts": {
     "no-restricted-syntax": {
-      "count": 5
+      "count": 1
     }
   },
-  "packages/core-backend/src/api/shared-types.ts": {
+  "packages/core-backend/src/ws/BackendWebSocketService.test.ts": {
     "no-restricted-syntax": {
       "count": 1
     }
   },
-  "packages/core-backend/src/index.ts": {
+  "packages/core-backend/src/ws/BackendWebSocketService.ts": {
     "no-restricted-syntax": {
+      "count": 5
+    }
+  },
+  "packages/core-backend/src/ws/ohlcv/OHLCVService.test.ts": {
+    "@typescript-eslint/naming-convention": {
       "count": 2
+    },
+    "id-length": {
+      "count": 1
+    },
+    "no-restricted-syntax": {
+      "count": 1
     }
   },
   "packages/delegation-controller/src/DelegationController.test.ts": {

packages/core-backend/CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `OHLCVService` for real-time OHLCV (candlestick) data streaming via WebSocket ([#8695](https://github.com/MetaMask/core/pull/8695))
+  - Wraps `BackendWebSocketService` through the messenger pattern to provide subscribe/unsubscribe semantics for market-data OHLCV channels
+  - Includes reference counting, grace-period unsubscribe, idempotency checks, chain-status forwarding, and automatic resubscription on reconnect
+- Export new types `OHLCVBar`, `OHLCVSubscriptionOptions`, `OHLCVSystemNotificationData`, `OHLCVServiceOptions`, `OHLCVServiceActions`, `OHLCVServiceAllowedActions`, `OHLCVServiceBarUpdatedEvent`, `OHLCVServiceChainStatusChangedEvent`, `OHLCVServiceSubscriptionErrorEvent`, `OHLCVServiceEvents`, `OHLCVServiceAllowedEvents`, and `OHLCVServiceMessenger` ([#8695](https://github.com/MetaMask/core/pull/8695))
+- Export new constants `OHLCV_SERVICE_ALLOWED_ACTIONS` and `OHLCV_SERVICE_ALLOWED_EVENTS` for configuring the messenger ([#8695](https://github.com/MetaMask/core/pull/8695))
+
 ### Changed
 
 - Bump `@metamask/accounts-controller` from `^38.1.0` to `^38.1.1` ([#8774](https://github.com/MetaMask/core/pull/8774))

packages/core-backend/package.json

@@ -60,6 +60,7 @@
     "@metamask/profile-sync-controller": "^28.0.2",
     "@metamask/utils": "^11.9.0",
     "@tanstack/query-core": "^5.62.16",
+    "async-mutex": "^0.5.0",
     "uuid": "^8.3.2"
   },
   "devDependencies": {

packages/core-backend/src/index.ts

@@ -9,7 +9,7 @@ export {
   getCloseReason,
   WebSocketState,
   WebSocketEventType,
-} from './BackendWebSocketService';
+} from './ws/BackendWebSocketService';
 
 export type {
   BackendWebSocketServiceOptions,
@@ -24,7 +24,7 @@ export type {
   BackendWebSocketServiceConnectionStateChangedEvent,
   BackendWebSocketServiceEvents,
   BackendWebSocketServiceMessenger,
-} from './BackendWebSocketService';
+} from './ws/BackendWebSocketService';
 
 // ============================================================================
 // ACCOUNT ACTIVITY SERVICE
@@ -34,7 +34,7 @@ export {
   AccountActivityService,
   ACCOUNT_ACTIVITY_SERVICE_ALLOWED_ACTIONS,
   ACCOUNT_ACTIVITY_SERVICE_ALLOWED_EVENTS,
-} from './AccountActivityService';
+} from './ws/AccountActivityService';
 
 export type {
   SystemNotificationData,
@@ -49,7 +49,7 @@ export type {
   AccountActivityServiceEvents,
   AllowedEvents as AccountActivityServiceAllowedEvents,
   AccountActivityServiceMessenger,
-} from './AccountActivityService';
+} from './ws/AccountActivityService';
 
 // ============================================================================
 // SHARED TYPES
@@ -80,6 +80,31 @@ export type {
   ApiPlatformClientServiceMessenger,
 } from './ApiPlatformClientService';
 
+// ============================================================================
+// OHLCV SERVICE
+// ============================================================================
+
+export {
+  OHLCVService,
+  OHLCV_SERVICE_ALLOWED_ACTIONS,
+  OHLCV_SERVICE_ALLOWED_EVENTS,
+} from './ws/ohlcv';
+
+export type {
+  OHLCVBar,
+  OHLCVSubscriptionOptions,
+  OHLCVSystemNotificationData,
+  OHLCVServiceOptions,
+  OHLCVServiceActions,
+  OHLCVServiceAllowedActions,
+  OHLCVServiceBarUpdatedEvent,
+  OHLCVServiceChainStatusChangedEvent,
+  OHLCVServiceSubscriptionErrorEvent,
+  OHLCVServiceEvents,
+  OHLCVServiceAllowedEvents,
+  OHLCVServiceMessenger,
+} from './ws/ohlcv';
+
 // ============================================================================
 // API PLATFORM CLIENT
 // ============================================================================

packages/core-backend/src/AccountActivityService.test.ts → packages/core-backend/src/ws/AccountActivityService.test.ts

@@ -7,16 +7,16 @@ import type {
 } from '@metamask/messenger';
 import type { Hex } from '@metamask/utils';
 
-import { flushPromises } from '../../../tests/helpers';
+import { flushPromises } from '../../../../tests/helpers';
+import type { Transaction, BalanceUpdate } from '../types';
+import type { AccountActivityMessage } from '../types';
 import { AccountActivityService } from './AccountActivityService';
 import type {
   AccountActivityServiceMessenger,
   SubscriptionOptions,
 } from './AccountActivityService';
 import type { ServerNotificationMessage } from './BackendWebSocketService';
 import { WebSocketState } from './BackendWebSocketService';
-import type { Transaction, BalanceUpdate } from './types';
-import type { AccountActivityMessage } from './types';
 
 type AllAccountActivityServiceActions =
   MessengerActions<AccountActivityServiceMessenger>;

packages/core-backend/src/AccountActivityService.ts → packages/core-backend/src/ws/AccountActivityService.ts

@@ -13,6 +13,12 @@ import type { TraceCallback } from '@metamask/controller-utils';
 import type { InternalAccount } from '@metamask/keyring-internal-api';
 import type { Messenger } from '@metamask/messenger';
 
+import { projectLogger, createModuleLogger } from '../logger';
+import type {
+  Transaction,
+  AccountActivityMessage,
+  BalanceUpdate,
+} from '../types';
 import type { AccountActivityServiceMethodActions } from './AccountActivityService-method-action-types';
 import type {
   WebSocketConnectionInfo,
@@ -21,12 +27,6 @@ import type {
 } from './BackendWebSocketService';
 import { WebSocketState } from './BackendWebSocketService';
 import type { BackendWebSocketServiceMethodActions } from './BackendWebSocketService-method-action-types';
-import { projectLogger, createModuleLogger } from './logger';
-import type {
-  Transaction,
-  AccountActivityMessage,
-  BalanceUpdate,
-} from './types';
 
 // =============================================================================
 // Types and Constants

packages/core-backend/src/BackendWebSocketService.test.ts → packages/core-backend/src/ws/BackendWebSocketService.test.ts

@@ -5,7 +5,7 @@ import type {
   MockAnyNamespace,
 } from '@metamask/messenger';
 
-import { flushPromises } from '../../../tests/helpers';
+import { flushPromises } from '../../../../tests/helpers';
 import {
   BackendWebSocketService,
   getCloseReason,

packages/core-backend/src/BackendWebSocketService.ts → packages/core-backend/src/ws/BackendWebSocketService.ts

@@ -9,8 +9,8 @@ import type { AuthenticationController } from '@metamask/profile-sync-controller
 import { getErrorMessage } from '@metamask/utils';
 import { v4 as uuidV4 } from 'uuid';
 
+import { projectLogger, createModuleLogger } from '../logger';
 import type { BackendWebSocketServiceMethodActions } from './BackendWebSocketService-method-action-types';
-import { projectLogger, createModuleLogger } from './logger';
 
 const SERVICE_NAME = 'BackendWebSocketService' as const;
 

packages/core-backend/src/ws/ohlcv/OHLCVService-method-action-types.ts

@@ -0,0 +1,40 @@
+/**
+ * This file is auto generated.
+ * Do not edit manually.
+ */
+
+import type { OHLCVService } from './OHLCVService';
+
+/**
+ * Subscribe to an OHLCV channel. If this is the first subscriber for the
+ * given asset/interval/currency combination a WebSocket subscription is
+ * created. Additional calls for the same combination only bump the reference
+ * count.
+ *
+ * @param options - The subscription parameters.
+ * @returns A promise that resolves once the subscription is established.
+ */
+export type OHLCVServiceSubscribeAction = {
+  type: `OHLCVService:subscribe`;
+  handler: OHLCVService['subscribe'];
+};
+
+/**
+ * Unsubscribe from an OHLCV channel. Decrements the reference count and,
+ * when it reaches zero, starts a grace-period timer before actually
+ * unsubscribing from the WebSocket to absorb rapid navigation patterns.
+ *
+ * @param options - The subscription parameters to unsubscribe from.
+ * @returns A promise that resolves once the unsubscription is processed.
+ */
+export type OHLCVServiceUnsubscribeAction = {
+  type: `OHLCVService:unsubscribe`;
+  handler: OHLCVService['unsubscribe'];
+};
+
+/**
+ * Union of all OHLCVService action types.
+ */
+export type OHLCVServiceMethodActions =
+  | OHLCVServiceSubscribeAction
+  | OHLCVServiceUnsubscribeAction;