refactor: Rewrite retryOnEmpty

Author: rekmarks

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

@@ -1,19 +1,19 @@
-import { errorCodes, providerErrors, rpcErrors } from '@metamask/rpc-errors';
+import { providerErrors, rpcErrors } from '@metamask/rpc-errors';
 import type { Json, JsonRpcParams, JsonRpcRequest } from '@metamask/utils';
 
 import { createRetryOnEmptyMiddleware } from '.';
 import type { ProviderRequestStub } from '../test/util/helpers';
 import {
   createMockParamsWithBlockParamAt,
   createMockParamsWithoutBlockParamAt,
-  createSimpleFinalMiddleware,
   createStubForBlockNumberRequest,
   expectProviderRequestNotToHaveBeenMade,
   requestMatches,
   stubProviderRequests,
   createProviderAndBlockTracker,
   createEngine,
   createRequest,
+  createFinalMiddlewareWithDefaultResult,
 } from '../test/util/helpers';
 
 const originalSetTimeout = globalThis.setTimeout;
@@ -100,18 +100,14 @@ describe('createRetryOnEmptyMiddleware', () => {
             }),
           ]);
 
-          const responsePromise = engine.handle(request);
+          const resultPromise = engine.handle(request);
           await waitForRequestToBeRetried({
             requestSpy,
             request,
             numberOfTimes: 10,
           });
 
-          expect(await responsePromise).toStrictEqual({
-            id: 1,
-            jsonrpc: '2.0',
-            result: 'something',
-          });
+          expect(await resultPromise).toBe('something');
         });
 
         it('returns an error if the request is still unsuccessful after 10 retries', async () => {
@@ -141,26 +137,20 @@ describe('createRetryOnEmptyMiddleware', () => {
             }),
           ]);
 
-          const responsePromise = engine.handle(request);
+          const resultPromise = engine.handle(request);
           await waitForRequestToBeRetried({
             requestSpy,
             request,
             numberOfTimes: 10,
           });
 
-          expect(await responsePromise).toMatchObject({
-            error: expect.objectContaining({
-              data: expect.objectContaining({
-                cause: expect.objectContaining({
-                  message: 'RetryOnEmptyMiddleware - retries exhausted',
-                }),
-              }),
-            }),
-          });
+          await expect(resultPromise).rejects.toThrow(
+            new Error('RetryOnEmptyMiddleware - retries exhausted'),
+          );
         });
 
         it('does not proceed to the next middleware after making a request through the provider', async () => {
-          const finalMiddleware = createSimpleFinalMiddleware();
+          const finalMiddleware = createFinalMiddlewareWithDefaultResult();
 
           const engine = createEngine(
             createRetryOnEmptyMiddleware({
@@ -219,7 +209,7 @@ describe('createRetryOnEmptyMiddleware', () => {
           });
 
           it('proceeds to the next middleware', async () => {
-            const finalMiddleware = createSimpleFinalMiddleware();
+            const finalMiddleware = createFinalMiddlewareWithDefaultResult();
 
             const engine = createEngine(
               createRetryOnEmptyMiddleware({
@@ -276,7 +266,7 @@ describe('createRetryOnEmptyMiddleware', () => {
             });
 
             it('proceeds to the next middleware', async () => {
-              const finalMiddleware = createSimpleFinalMiddleware();
+              const finalMiddleware = createFinalMiddlewareWithDefaultResult();
 
               const engine = createEngine(
                 createRetryOnEmptyMiddleware({
@@ -334,7 +324,7 @@ describe('createRetryOnEmptyMiddleware', () => {
             });
 
             it('proceeds to the next middleware', async () => {
-              const finalMiddleware = createSimpleFinalMiddleware();
+              const finalMiddleware = createFinalMiddlewareWithDefaultResult();
 
               const engine = createEngine(
                 createRetryOnEmptyMiddleware({
@@ -389,7 +379,7 @@ describe('createRetryOnEmptyMiddleware', () => {
           });
 
           it('proceeds to the next middleware', async () => {
-            const finalMiddleware = createSimpleFinalMiddleware();
+            const finalMiddleware = createFinalMiddlewareWithDefaultResult();
 
             const engine = createEngine(
               createRetryOnEmptyMiddleware({
@@ -437,7 +427,7 @@ describe('createRetryOnEmptyMiddleware', () => {
     });
 
     it('proceeds to the next middleware', async () => {
-      const finalMiddleware = createSimpleFinalMiddleware();
+      const finalMiddleware = createFinalMiddlewareWithDefaultResult();
 
       const engine = createEngine(
         createRetryOnEmptyMiddleware({
@@ -478,13 +468,11 @@ describe('createRetryOnEmptyMiddleware', () => {
           },
         },
       ]);
-      const responsePromise = engine.handle(request);
-      expect(await responsePromise).toMatchObject({
-        error: expect.objectContaining({
-          code: errorCodes.rpc.invalidInput,
-          message: 'execution reverted',
-        }),
-      });
+
+      const resultPromise = engine.handle(request);
+      await expect(resultPromise).rejects.toThrow(
+        rpcErrors.invalidInput('execution reverted'),
+      );
     });
   });
 });

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

@@ -1,9 +1,8 @@
 import type { PollingBlockTracker } from '@metamask/eth-block-tracker';
 import type { InternalProvider } from '@metamask/eth-json-rpc-provider';
-import type { JsonRpcMiddleware } from '@metamask/json-rpc-engine';
-import { createAsyncMiddleware } from '@metamask/json-rpc-engine';
-import type { Json, JsonRpcParams } from '@metamask/utils';
-import { klona } from 'klona/full';
+import type { JsonRpcMiddleware } from '@metamask/json-rpc-engine/v2';
+import type { Json, JsonRpcParams, JsonRpcRequest } from '@metamask/utils';
+import { klona } from 'klona';
 
 import { projectLogger, createModuleLogger } from './logging-utils';
 import type { Block } from './types';
@@ -41,7 +40,7 @@ export function createRetryOnEmptyMiddleware({
 }: {
   provider?: InternalProvider;
   blockTracker?: PollingBlockTracker;
-} = {}): JsonRpcMiddleware<JsonRpcParams, Json> {
+} = {}): JsonRpcMiddleware<JsonRpcRequest, Json> {
   if (!provider) {
     throw Error(
       'RetryOnEmptyMiddleware - mandatory "provider" option is missing.',
@@ -54,16 +53,18 @@ export function createRetryOnEmptyMiddleware({
     );
   }
 
-  return createAsyncMiddleware(async (req, res, next) => {
-    const blockRefIndex: number | undefined = blockTagParamIndex(req.method);
+  return async ({ request, next }) => {
+    const blockRefIndex: number | undefined = blockTagParamIndex(
+      request.method,
+    );
     // skip if method does not include blockRef
     if (blockRefIndex === undefined) {
       return next();
     }
     // skip if not exact block references
     let blockRef: string | undefined =
-      Array.isArray(req.params) && req.params[blockRefIndex]
-        ? (req.params[blockRefIndex] as string)
+      Array.isArray(request.params) && request.params[blockRefIndex]
+        ? (request.params[blockRefIndex] as string)
         : undefined;
     // omitted blockRef implies "latest"
     if (blockRef === undefined) {
@@ -102,7 +103,7 @@ export function createRetryOnEmptyMiddleware({
     );
 
     // create child request with specific block-ref
-    const childRequest = klona(req);
+    const childRequest = klona(request);
     // attempt child request until non-empty response is received
     const childResult = await retry(10, async () => {
       log('Performing request %o', childRequest);
@@ -122,10 +123,8 @@ export function createRetryOnEmptyMiddleware({
       return attemptResult;
     });
     log('Copying result %o', childResult);
-    // copy child result onto original response
-    res.result = childResult;
-    return undefined;
-  });
+    return childResult;
+  };
 }
 
 /**

packages/eth-json-rpc-middleware/test/util/helpers.ts

@@ -120,18 +120,6 @@ export function createEngine(
   });
 }
 
-/**
- * Creates a middleware function that just ends the request, but is also a Jest
- * mock function so that you can make assertions on it.
- *
- * @returns The created middleware, as a mock function.
- */
-export function createSimpleFinalMiddleware() {
-  return jest.fn((_req, _res, _next, end) => {
-    end();
-  });
-}
-
 /**
  * Some JSON-RPC endpoints take a "block" param (example: `eth_blockNumber`)
  * which can optionally be left out. Additionally, the endpoint may support some