feat: Add providerAsMiddlewareV2

Author: rekmarks

eslint-warning-thresholds.json

@@ -180,7 +180,7 @@
     "jsdoc/match-description": 4
   },
   "packages/eth-json-rpc-middleware/src/methods/wallet-request-execution-permissions.ts": {
-    "jsdoc/require-jsdoc": 1
+    "jsdoc/require-jsdoc": 2
   },
   "packages/eth-json-rpc-middleware/src/methods/wallet-revoke-execution-permission.ts": {
     "jsdoc/require-jsdoc": 1

packages/eth-json-rpc-middleware/src/index.test.ts

@@ -13,6 +13,7 @@ describe('index module', () => {
         "createRetryOnEmptyMiddleware": [Function],
         "createWalletMiddleware": [Function],
         "providerAsMiddleware": [Function],
+        "providerAsMiddlewareV2": [Function],
       }
     `);
   });

packages/eth-json-rpc-middleware/src/providerAsMiddleware.test.ts

@@ -0,0 +1,59 @@
+import type { SafeEventEmitterProvider } from '@metamask/eth-json-rpc-provider';
+import { JsonRpcEngine } from '@metamask/json-rpc-engine';
+import { JsonRpcEngineV2 } from '@metamask/json-rpc-engine/v2';
+import { assertIsJsonRpcSuccess, Json } from '@metamask/utils';
+
+import { providerAsMiddleware, providerAsMiddlewareV2 } from './providerAsMiddleware';
+import { createRequest } from '../test/util/helpers';
+
+const createMockProvider = (result: Json): SafeEventEmitterProvider =>
+  ({
+    request: jest.fn().mockResolvedValue(result),
+  } as unknown as SafeEventEmitterProvider);
+
+describe('providerAsMiddleware', () => {
+  it('forwards requests to the provider and returns the result', async () => {
+    const mockResult = 42;
+    const mockProvider = createMockProvider(mockResult);
+
+    const engine = new JsonRpcEngine();
+    engine.push(providerAsMiddleware(mockProvider));
+
+    const request = createRequest({
+      method: 'eth_chainId',
+      params: [],
+    });
+
+    await new Promise<void>((resolve) => {
+      engine.handle(request, (error, response) => {
+        expect(error).toBeNull();
+        expect(response).toBeDefined();
+        assertIsJsonRpcSuccess(response);
+        expect(response.result).toEqual(mockResult);
+        expect(mockProvider.request).toHaveBeenCalledWith(request);
+        resolve();
+      });
+    });
+  });
+});
+
+describe('providerAsMiddlewareV2', () => {
+  it('forwards requests to the provider and returns the result', async () => {
+    const mockResult = 123;
+    const mockProvider = createMockProvider(mockResult);
+
+    const engine = JsonRpcEngineV2.create({
+      middleware: [providerAsMiddlewareV2(mockProvider)],
+    });
+
+    const request = createRequest({
+      method: 'eth_chainId',
+      params: [],
+    });
+
+    const result = await engine.handle(request);
+
+    expect(result).toEqual(mockResult);
+    expect(mockProvider.request).toHaveBeenCalledWith(request);
+  });
+});

packages/eth-json-rpc-middleware/src/providerAsMiddleware.ts

@@ -1,14 +1,21 @@
 import type { InternalProvider } from '@metamask/eth-json-rpc-provider';
 import {
   createAsyncMiddleware,
-  type JsonRpcMiddleware,
+  type JsonRpcMiddleware as LegacyJsonRpcMiddleware,
 } from '@metamask/json-rpc-engine';
-import type { Json, JsonRpcParams } from '@metamask/utils';
+import type { JsonRpcMiddleware } from '@metamask/json-rpc-engine/v2';
+import type { Json, JsonRpcParams, JsonRpcRequest } from '@metamask/utils';
 
 export function providerAsMiddleware(
   provider: InternalProvider,
-): JsonRpcMiddleware<JsonRpcParams, Json> {
+): LegacyJsonRpcMiddleware<JsonRpcParams, Json> {
   return createAsyncMiddleware(async (req, res) => {
     res.result = await provider.request(req);
   });
 }
+
+export function providerAsMiddlewareV2(
+  provider: InternalProvider,
+): JsonRpcMiddleware<JsonRpcRequest, Json> {
+  return async ({ request }) => provider.request(request);
+}