feat: Add WebSockets support (#3450)

Implements the rewritten SIP-20 to enable WebSocket support in Snaps.

WebSockets are supported via the `WebSocketService` which runs in the
client and handles open WebSocket connections for the Snap. The Snap is
notified of WebSocket events via `onWebSocketEvent` and is notified of
`open`, `close` and `message`. Messages can also be sent from the Snap
using `snap_sendWebSocketMessage`. Both string and binary payloads are
allowed.

All of the new RPC methods are gated on `endowment:network-access`,
which is also the permission required to expose `onWebSocketEvent`.

Author: FrederikBolding

packages/snaps-controllers/coverage.json

@@ -1,6 +1,6 @@
 {
-  "branches": 95.29,
-  "functions": 98.65,
-  "lines": 98.83,
-  "statements": 98.66
+  "branches": 95.21,
+  "functions": 98.71,
+  "lines": 98.87,
+  "statements": 98.7
 }

packages/snaps-controllers/src/index.ts

@@ -6,3 +6,4 @@ export * from './cronjob';
 export * from './interface';
 export * from './insights';
 export * from './multichain';
+export * from './websocket';

packages/snaps-controllers/src/snaps/SnapController.test.tsx

@@ -6940,7 +6940,7 @@ describe('SnapController', () => {
           [MOCK_SNAP_ID]: {},
         }),
       ).rejects.toThrow(
-        'A snap must request at least one of the following permissions: endowment:rpc, endowment:transaction-insight, endowment:cronjob, endowment:name-lookup, endowment:lifecycle-hooks, endowment:keyring, endowment:page-home, endowment:page-settings, endowment:signature-insight, endowment:assets, endowment:protocol.',
+        'A snap must request at least one of the following permissions: endowment:rpc, endowment:transaction-insight, endowment:cronjob, endowment:name-lookup, endowment:lifecycle-hooks, endowment:keyring, endowment:page-home, endowment:page-settings, endowment:signature-insight, endowment:assets, endowment:protocol, endowment:network-access.',
       );
 
       controller.destroy();

packages/snaps-controllers/src/snaps/constants.ts

@@ -43,4 +43,5 @@ export const CLIENT_ONLY_HANDLERS = Object.freeze([
   HandlerType.OnAssetsLookup,
   HandlerType.OnAssetsConversion,
   HandlerType.OnAssetHistoricalPrice,
+  HandlerType.OnWebSocketEvent,
 ]);

packages/snaps-controllers/src/snaps/index.ts

@@ -1,3 +1,4 @@
+export * from './constants';
 export * from './location';
 export * from './SnapController';
 export * from './selectors';

packages/snaps-controllers/src/test-utils/controller.ts

@@ -71,6 +71,11 @@ import type {
   SnapsRegistryEvents,
 } from '../snaps';
 import type { KeyDerivationOptions } from '../types';
+import type {
+  WebSocketServiceActions,
+  WebSocketServiceAllowedActions,
+  WebSocketServiceEvents,
+} from '../websocket';
 
 const asyncNoOp = async () => Promise.resolve();
 
@@ -962,3 +967,37 @@ export const getRestrictedMultichainRouterMessenger = (
 
   return controllerMessenger;
 };
+
+// Mock controller messenger for WebSocketService
+export const getRootWebSocketServiceMessenger = () => {
+  const messenger = new MockControllerMessenger<
+    WebSocketServiceActions | WebSocketServiceAllowedActions,
+    WebSocketServiceEvents
+  >();
+
+  jest.spyOn(messenger, 'call');
+
+  return messenger;
+};
+
+export const getRestrictedWebSocketServiceMessenger = (
+  messenger: ReturnType<
+    typeof getRootWebSocketServiceMessenger
+  > = getRootWebSocketServiceMessenger(),
+) => {
+  const controllerMessenger = messenger.getRestricted<
+    'WebSocketService',
+    WebSocketServiceAllowedActions['type'],
+    WebSocketServiceEvents['type']
+  >({
+    name: 'WebSocketService',
+    allowedEvents: [
+      'SnapController:snapInstalled',
+      'SnapController:snapUpdated',
+      'SnapController:snapUninstalled',
+    ],
+    allowedActions: ['SnapController:handleRequest'],
+  });
+
+  return controllerMessenger;
+};