feat: Add support for using the messenger in preinstalled Snaps

packages/examples/packages/preinstalled/package.json

@@ -46,6 +46,7 @@
     "@jest/globals": "^29.5.0",
     "@lavamoat/allow-scripts": "^4.0.0",
     "@metamask/auto-changelog": "^6.1.1",
+    "@metamask/messenger": "^1.2.0",
     "@metamask/snaps-cli": "workspace:^",
     "@metamask/snaps-jest": "workspace:^",
     "@metamask/snaps-sdk": "workspace:^",

packages/examples/packages/preinstalled/snap.manifest.json

@@ -7,7 +7,7 @@
     "url": "https://github.com/MetaMask/snaps.git"
   },
   "source": {
-    "shasum": "HEK+eFeY5FqLG4XSbZzP7BoXJgXptNV0lHtuxuFEym8=",
+    "shasum": "4Orr2LFWey4elfpvTf6tdUOBsaVCnahshTHv3v9Bf7I=",
     "location": {
       "npm": {
         "filePath": "dist/bundle.js",
@@ -25,7 +25,10 @@
     },
     "snap_dialog": {},
     "endowment:page-settings": {},
-    "snap_manageState": {}
+    "snap_manageState": {},
+    "endowment:messenger": {
+      "actions": ["PhishingController:testOrigin"]
+    }
   },
   "platformVersion": "11.1.1",
   "manifestVersion": "0.1"

packages/examples/packages/preinstalled/src/index.test.tsx

@@ -150,6 +150,18 @@ describe('onRpcRequest', () => {
       });
     });
   });
+
+  describe('messengerCall', () => {
+    it('calls the PhishingController', async () => {
+      const { request } = await installSnap();
+
+      const response = await request({
+        method: 'messengerCall',
+      });
+
+      expect(response).toRespondWith(false);
+    });
+  });
 });
 
 describe('onSettingsPage', () => {

packages/examples/packages/preinstalled/src/index.tsx

@@ -1,5 +1,7 @@
+import type { Messenger } from '@metamask/messenger';
 import {
   getJsonError,
+  getMessenger,
   MethodNotFoundError,
   UserInputEventType,
 } from '@metamask/snaps-sdk';
@@ -17,6 +19,13 @@ type SnapState = {
   setting3?: 'option1' | 'option2';
 };
 
+type PhishingControllerTestOrigin = {
+  type: 'PhishingController:testOrigin';
+  handler: (origin: string) => { result: boolean; type: string };
+};
+
+type SnapMessenger = Messenger<string, PhishingControllerTestOrigin>;
+
 /**
  * Handle incoming JSON-RPC requests from the dapp, sent through the
  * `wallet_invokeSnap` method. This handler handles the following methods:
@@ -97,6 +106,15 @@ export const onRpcRequest: OnRpcRequestHandler = async ({ request }) => {
       });
     }
 
+    case 'messengerCall': {
+      const messenger = getMessenger<SnapMessenger>();
+      const { result } = await messenger.call(
+        'PhishingController:testOrigin',
+        'https://metamask.io',
+      );
+      return result;
+    }
+
     default:
       throw new MethodNotFoundError({ method: request.method });
   }

packages/snaps-execution-environments/lavamoat/webpack/iframe/policy.json

@@ -2,7 +2,7 @@
   "resources": {
     "@metamask/json-rpc-engine": {
       "packages": {
-        "@metamask/snaps-utils>@metamask/messenger": true,
+        "@metamask/snaps-sdk>@metamask/messenger": true,
         "@metamask/rpc-errors": true,
         "@metamask/providers>@metamask/safe-event-emitter": true,
         "@metamask/utils": true

packages/snaps-execution-environments/lavamoat/webpack/node-process/policy.json

@@ -2,7 +2,7 @@
   "resources": {
     "@metamask/json-rpc-engine": {
       "packages": {
-        "@metamask/snaps-utils>@metamask/messenger": true,
+        "@metamask/snaps-sdk>@metamask/messenger": true,
         "@metamask/rpc-errors": true,
         "@metamask/providers>@metamask/safe-event-emitter": true,
         "@metamask/utils": true

packages/snaps-execution-environments/lavamoat/webpack/node-thread/policy.json

@@ -2,7 +2,7 @@
   "resources": {
     "@metamask/json-rpc-engine": {
       "packages": {
-        "@metamask/snaps-utils>@metamask/messenger": true,
+        "@metamask/snaps-sdk>@metamask/messenger": true,
         "@metamask/rpc-errors": true,
         "@metamask/providers>@metamask/safe-event-emitter": true,
         "@metamask/utils": true

packages/snaps-execution-environments/lavamoat/webpack/webview/policy.json

@@ -2,7 +2,7 @@
   "resources": {
     "@metamask/json-rpc-engine": {
       "packages": {
-        "@metamask/snaps-utils>@metamask/messenger": true,
+        "@metamask/snaps-sdk>@metamask/messenger": true,
         "@metamask/rpc-errors": true,
         "@metamask/providers>@metamask/safe-event-emitter": true,
         "@metamask/utils": true

packages/snaps-rpc-methods/jest.config.js

@@ -10,10 +10,10 @@ module.exports = deepmerge(baseConfig, {
   ],
   coverageThreshold: {
     global: {
-      branches: 97.28,
-      functions: 98.88,
-      lines: 99.19,
-      statements: 98.91,
+      branches: 97.38,
+      functions: 98.92,
+      lines: 99.22,
+      statements: 98.95,
     },
   },
 });

packages/snaps-rpc-methods/src/endowments/enum.ts

@@ -14,4 +14,5 @@ export enum SnapEndowments {
   SettingsPage = 'endowment:page-settings',
   Assets = 'endowment:assets',
   Protocol = 'endowment:protocol',
+  Messenger = 'endowment:messenger',
 }

packages/snaps-rpc-methods/src/endowments/index.ts

@@ -21,6 +21,11 @@ import {
   keyringEndowmentBuilder,
 } from './keyring';
 import { lifecycleHooksEndowmentBuilder } from './lifecycle-hooks';
+import {
+  getMessengerCaveatMapper,
+  messengerCaveatSpecifications,
+  messengerEndowmentBuilder,
+} from './messenger';
 import { multichainProviderEndowmentBuilder } from './multichain-provider';
 import {
   getNameLookupCaveatMapper,
@@ -71,6 +76,7 @@ export const endowmentPermissionBuilders = {
   [signatureInsightEndowmentBuilder.targetName]:
     signatureInsightEndowmentBuilder,
   [assetsEndowmentBuilder.targetName]: assetsEndowmentBuilder,
+  [messengerEndowmentBuilder.targetName]: messengerEndowmentBuilder,
 } as const;
 
 export const endowmentCaveatSpecifications = {
@@ -82,6 +88,7 @@ export const endowmentCaveatSpecifications = {
   ...signatureInsightCaveatSpecifications,
   ...maxRequestTimeCaveatSpecifications,
   ...protocolCaveatSpecifications,
+  ...messengerCaveatSpecifications,
 };
 
 export const endowmentCaveatMappers: Record<
@@ -114,6 +121,7 @@ export const endowmentCaveatMappers: Record<
   [assetsEndowmentBuilder.targetName]: createMaxRequestTimeMapper(
     getAssetsCaveatMapper,
   ),
+  [messengerEndowmentBuilder.targetName]: getMessengerCaveatMapper,
 };
 
 // We allow null because a permitted handler does not have an endowment

packages/snaps-rpc-methods/src/endowments/messenger.test.ts

@@ -0,0 +1,149 @@
+import { PermissionType, SubjectType } from '@metamask/permission-controller';
+import { SnapCaveatType } from '@metamask/snaps-utils';
+
+import { SnapEndowments } from './enum';
+import {
+  getMessengerCaveatMapper,
+  messengerCaveatSpecifications,
+  messengerEndowmentBuilder,
+  getMessengerCaveatActions,
+} from './messenger';
+
+describe('endowment:messenger', () => {
+  it('builds the expected permission specification', () => {
+    const specification = messengerEndowmentBuilder.specificationBuilder({});
+    expect(specification).toStrictEqual({
+      permissionType: PermissionType.Endowment,
+      targetName: SnapEndowments.Messenger,
+      endowmentGetter: expect.any(Function),
+      allowedCaveats: [SnapCaveatType.MessengerScopes],
+      subjectTypes: [SubjectType.Snap],
+      validator: expect.any(Function),
+    });
+
+    expect(specification.endowmentGetter()).toBeNull();
+  });
+
+  describe('validator', () => {
+    it('throws if the caveat is not a single "messengerScopes"', () => {
+      const specification = messengerEndowmentBuilder.specificationBuilder({});
+
+      expect(() =>
+        specification.validator({
+          // @ts-expect-error Missing other required permission types.
+          caveats: undefined,
+        }),
+      ).toThrow('Expected the following caveats: "messengerScopes".');
+
+      expect(() =>
+        // @ts-expect-error Missing other required permission types.
+        specification.validator({
+          caveats: [{ type: 'foo', value: 'bar' }],
+        }),
+      ).toThrow(
+        'Expected the following caveats: "messengerScopes", received "foo".',
+      );
+
+      expect(() =>
+        // @ts-expect-error Missing other required permission types.
+        specification.validator({
+          caveats: [
+            { type: SnapCaveatType.MessengerScopes, value: 'bar' },
+            { type: SnapCaveatType.MessengerScopes, value: 'bar' },
+          ],
+        }),
+      ).toThrow('Duplicate caveats are not allowed.');
+    });
+  });
+});
+
+describe('getMessengerCaveatMapper', () => {
+  it('maps a value to a caveat', () => {
+    expect(
+      getMessengerCaveatMapper({
+        actions: ['Foo:bar'],
+      }),
+    ).toStrictEqual({
+      caveats: [
+        {
+          type: SnapCaveatType.MessengerScopes,
+          value: {
+            actions: ['Foo:bar'],
+          },
+        },
+      ],
+    });
+  });
+
+  it('returns null if value is empty', () => {
+    expect(getMessengerCaveatMapper({})).toStrictEqual({ caveats: null });
+  });
+});
+
+describe('getMessengerCaveatActions', () => {
+  it('returns the actions from the caveat', () => {
+    expect(
+      // @ts-expect-error Missing other required permission types.
+      getMessengerCaveatActions({
+        caveats: [
+          {
+            type: SnapCaveatType.MessengerScopes,
+            value: { actions: ['Foo:bar'] },
+          },
+        ],
+      }),
+    ).toStrictEqual(['Foo:bar']);
+  });
+
+  it('returns null if no caveat found', () => {
+    expect(
+      // @ts-expect-error Missing other required permission types.
+      getMessengerCaveatActions({
+        caveats: null,
+      }),
+    ).toBeNull();
+  });
+});
+
+describe('messengerCaveatSpecifications', () => {
+  describe('validator', () => {
+    it('throws if the caveat values are invalid', () => {
+      expect(() =>
+        messengerCaveatSpecifications[
+          SnapCaveatType.MessengerScopes
+        ].validator?.(
+          // @ts-expect-error Missing value type.
+          {
+            type: SnapCaveatType.MessengerScopes,
+          },
+        ),
+      ).toThrow('Expected an object.');
+
+      expect(() =>
+        messengerCaveatSpecifications[
+          SnapCaveatType.MessengerScopes
+        ].validator?.({
+          type: SnapCaveatType.MessengerScopes,
+          value: {
+            foo: 'bar',
+          },
+        }),
+      ).toThrow(
+        'Invalid messenger scopes specified: At path: foo -- Expected a value of type `never`, but received: `"bar"`',
+      );
+
+      expect(() =>
+        messengerCaveatSpecifications[
+          SnapCaveatType.MessengerScopes
+        ].validator?.({
+          type: SnapCaveatType.MessengerScopes,
+          value: {
+            actions: [],
+          },
+        }),
+      ).toThrow(
+        'Invalid messenger scopes specified: At path: actions -- Expected a array with a length between `1` and `Infinity` but received one with a length of `0`.',
+      );
+    });
+  });
+});