web3 middleware

packages/web3-core/src/types.ts

@@ -15,7 +15,7 @@ You should have received a copy of the GNU Lesser General Public License
 along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-import { HexString, Transaction } from 'web3-types';
+import { HexString, JsonRpcResponse, Transaction, Web3APIMethod, Web3APIRequest, Web3APIReturnType } from 'web3-types';
 
 export type TransactionTypeParser = (
 	transaction: Transaction,
@@ -30,3 +30,18 @@ export interface ExtensionObject {
 	property?: string;
 	methods: Method[];
 }
+
+export interface RequestManagerMiddleware<API> {
+	processRequest<
+		AnotherMethod extends Web3APIMethod<API>
+	>(
+		request: Web3APIRequest<API, AnotherMethod>, 
+		options?: { [key: string]: unknown }): Promise<Web3APIRequest<API, AnotherMethod>>;
+
+	processResponse<
+		AnotherMethod extends Web3APIMethod<API>,
+		ResponseType = Web3APIReturnType<API, AnotherMethod>>
+	(
+		response: JsonRpcResponse<ResponseType>, 
+		options?: { [key: string]: unknown }): Promise<JsonRpcResponse<ResponseType>>;
+  }

packages/web3-core/src/web3_context.ts

@@ -25,7 +25,7 @@ import { isNullish } from 'web3-utils';
 import { BaseTransaction, TransactionFactory } from 'web3-eth-accounts';
 import { isSupportedProvider } from './utils.js';
 // eslint-disable-next-line import/no-cycle
-import { ExtensionObject } from './types.js';
+import { ExtensionObject, RequestManagerMiddleware } from './types.js';
 import { Web3BatchRequest } from './web3_batch_request.js';
 // eslint-disable-next-line import/no-cycle
 import { Web3Config, Web3ConfigEvent, Web3ConfigOptions } from './web3_config.js';
@@ -65,6 +65,7 @@ export type Web3ContextInitOptions<
 	registeredSubscriptions?: RegisteredSubs;
 	accountProvider?: Web3AccountProvider<Web3BaseWalletAccount>;
 	wallet?: Web3BaseWallet<Web3BaseWalletAccount>;
+	requestManagerMiddleware?: RequestManagerMiddleware<API>;
 };
 
 // eslint-disable-next-line no-use-before-define
@@ -129,6 +130,7 @@ export class Web3Context<
 			registeredSubscriptions,
 			accountProvider,
 			wallet,
+			requestManagerMiddleware
 		} = providerOrContext as Web3ContextInitOptions<API, RegisteredSubs>;
 
 		this.setConfig(config ?? {});
@@ -138,6 +140,7 @@ export class Web3Context<
 			new Web3RequestManager<API>(
 				provider,
 				config?.enableExperimentalFeatures?.useSubscriptionWhenCheckingBlockTimeout,
+				requestManagerMiddleware
 			);
 
 		if (subscriptionManager) {
@@ -352,6 +355,11 @@ export class Web3Context<
 		this.provider = provider;
 		return true;
 	}
+
+	public setRequestManagerMiddleware(requestManagerMiddleware: RequestManagerMiddleware<API>){
+		this.requestManager.setMiddleware(requestManagerMiddleware);
+	}
+
 	/**
 	 * Will return the {@link Web3BatchRequest} constructor.
 	 */

packages/web3-core/src/web3_request_manager.ts

@@ -52,6 +52,7 @@ import {
 	isWeb3Provider,
 } from './utils.js';
 import { Web3EventEmitter } from './web3_event_emitter.js';
+import { RequestManagerMiddleware } from './types.js';
 
 export enum Web3RequestManagerEvent {
 	PROVIDER_CHANGED = 'PROVIDER_CHANGED',
@@ -73,18 +74,25 @@ export class Web3RequestManager<
 }> {
 	private _provider?: SupportedProviders<API>;
 	private readonly useRpcCallSpecification?: boolean;
+	public middleware?: RequestManagerMiddleware<API>;
+
 	public constructor(
 		provider?: SupportedProviders<API> | string,
 		useRpcCallSpecification?: boolean,
+		requestManagerMiddleware?: RequestManagerMiddleware<API>
 	) {
 		super();
 
 		if (!isNullish(provider)) {
 			this.setProvider(provider);
 		}
 		this.useRpcCallSpecification = useRpcCallSpecification;
-	}
 
+		if (!isNullish(requestManagerMiddleware))
+			this.middleware = requestManagerMiddleware;
+
+	}
+
 	/**
 	 * Will return all available providers
 	 */
@@ -142,6 +150,10 @@ export class Web3RequestManager<
 		return true;
 	}
 
+	public setMiddleware(requestManagerMiddleware: RequestManagerMiddleware<API>){
+		this.middleware = requestManagerMiddleware;
+	}
+
 	/**
 	 *
 	 * Will execute a request
@@ -155,7 +167,17 @@ export class Web3RequestManager<
 		Method extends Web3APIMethod<API>,
 		ResponseType = Web3APIReturnType<API, Method>,
 	>(request: Web3APIRequest<API, Method>): Promise<ResponseType> {
-		const response = await this._sendRequest<Method, ResponseType>(request);
+
+		let requestObj = {...request};
+
+		if (!isNullish(this.middleware))
+		requestObj = await this.middleware.processRequest(requestObj);
+
+		let response = await this._sendRequest<Method, ResponseType>(requestObj);
+
+		if (!isNullish(this.middleware))
+			response = await this.middleware.processResponse(response);
+
 		if (jsonRpc.isResponseWithResult(response)) {
 			return response.result;
 		}

packages/web3-core/test/unit/web3_context.test.ts

@@ -18,8 +18,10 @@ along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
 // eslint-disable-next-line max-classes-per-file
 import { ExistingPluginNamespaceError } from 'web3-errors';
 import HttpProvider from 'web3-providers-http';
+import { EthExecutionAPI, JsonRpcResponse, Web3APIMethod, Web3APIRequest, Web3APIReturnType } from 'web3-types';
 import { Web3Context, Web3PluginBase } from '../../src/web3_context';
 import { Web3RequestManager } from '../../src/web3_request_manager';
+import { RequestManagerMiddleware } from '../../src/types';
 
 // eslint-disable-next-line @typescript-eslint/ban-types
 class Context1 extends Web3Context<{}> {}
@@ -63,6 +65,19 @@ describe('Web3Context', () => {
 
 			expect(context.currentProvider).toBeInstanceOf(HttpProvider);
 		});
+
+		it('should set middleware for the request manager', () => {
+			const context = new Web3Context('http://test.com');
+
+			const middleware: RequestManagerMiddleware<EthExecutionAPI>
+			  = {
+				processRequest: jest.fn(async <Method extends Web3APIMethod<EthExecutionAPI>>(request: Web3APIRequest<EthExecutionAPI, Method>) => request),
+				processResponse: jest.fn(async <Method extends Web3APIMethod<EthExecutionAPI>, ResponseType = Web3APIReturnType<EthExecutionAPI, Method>>(response: JsonRpcResponse<ResponseType>) => response),
+			  };
+
+			context.setRequestManagerMiddleware(middleware);
+			expect(context.requestManager.middleware).toEqual(middleware);
+		});
 	});
 
 	describe('getContextObject', () => {

packages/web3-core/test/unit/web3_middleware_request_manager.test.ts

@@ -0,0 +1,144 @@
+/*
+This file is part of web3.js.
+
+web3.js is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+web3.js is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import { EthExecutionAPI, JsonRpcResponse, Web3APIMethod, Web3APIRequest, Web3APIReturnType } from 'web3-types';
+import { jsonRpc } from 'web3-utils';
+import { RequestManagerMiddleware } from '../../src/types';
+import { Web3RequestManager } from '../../src/web3_request_manager';
+
+class Web3Middleware<API> implements RequestManagerMiddleware<API> {
+
+  // eslint-disable-next-line class-methods-use-this
+  public async processRequest<Method extends Web3APIMethod<API>>(
+    request: Web3APIRequest<API, Method>
+  ): Promise<Web3APIRequest<API, Method>> {
+    // Implement the processRequest logic here
+
+    let requestObj = {...request};
+    if (request.method === 'eth_call' && Array.isArray(request.params)) {
+      requestObj = {
+        ...requestObj,
+        params: [...request.params, '0x0', '0x1'],
+      };
+    }
+
+    return Promise.resolve(requestObj);
+  }
+
+  // eslint-disable-next-line class-methods-use-this
+  public async processResponse<
+    Method extends Web3APIMethod<API>,
+    ResponseType = Web3APIReturnType<API, Method>
+  >(
+    response: JsonRpcResponse<ResponseType>
+  ): Promise<JsonRpcResponse<ResponseType>> {
+
+    let responseObj = {...response};
+    if (!jsonRpc.isBatchResponse(responseObj) && responseObj.id === 1) {
+      responseObj = {
+        ...responseObj,
+        result: '0x6a756e616964' as any,
+      };
+    }
+
+    return Promise.resolve(responseObj);
+  }
+}
+
+describe('Request Manager Middleware', () => {
+  let requestManagerMiddleware: RequestManagerMiddleware<EthExecutionAPI>;
+
+  beforeAll(() => { 
+    requestManagerMiddleware = {
+      processRequest: jest.fn(async <Method extends Web3APIMethod<EthExecutionAPI>>(request: Web3APIRequest<EthExecutionAPI, Method>) => request),
+      processResponse: jest.fn(async <Method extends Web3APIMethod<EthExecutionAPI>, ResponseType = Web3APIReturnType<EthExecutionAPI, Method>>(response: JsonRpcResponse<ResponseType>) => response),
+    };
+
+  });
+
+  it('should set requestManagerMiddleware via constructor', () => {
+    const web3RequestManager1: Web3RequestManager = new Web3RequestManager<EthExecutionAPI>(undefined, true, requestManagerMiddleware);
+
+    expect(web3RequestManager1.middleware).toBeDefined();
+    expect(web3RequestManager1.middleware).toEqual(requestManagerMiddleware);
+  });
+
+  it('should set requestManagerMiddleware via set method', () => {
+
+    const middleware2: RequestManagerMiddleware<EthExecutionAPI> = new Web3Middleware<EthExecutionAPI>();
+    const web3RequestManager2: Web3RequestManager = new Web3RequestManager<EthExecutionAPI>('http://localhost:8181');
+    web3RequestManager2.setMiddleware(middleware2);
+
+    expect(web3RequestManager2.middleware).toBeDefined();
+    expect(web3RequestManager2.middleware).toEqual(middleware2);
+  });
+
+  it('should call processRequest and processResponse functions of requestManagerMiddleware', async () => {
+
+    const web3RequestManager3 = new Web3RequestManager<EthExecutionAPI>('http://localhost:8080', true, requestManagerMiddleware );
+
+    const expectedResponse: JsonRpcResponse<string> = {
+        jsonrpc: '2.0',
+        id: 1,
+        result: '0x0',
+      };
+
+    jest.spyOn(web3RequestManager3 as any, '_sendRequest').mockResolvedValue(expectedResponse);
+
+    const request = {
+      id: 1,
+      method: 'eth_call',
+      params: [],
+    };
+
+    await web3RequestManager3.send(request);
+
+    expect(requestManagerMiddleware.processRequest).toHaveBeenCalledWith(request);
+    expect(requestManagerMiddleware.processResponse).toHaveBeenCalled();
+  });
+
+  it('should allow modification of request and response', async () => {
+
+    const middleware3: RequestManagerMiddleware<EthExecutionAPI> = new Web3Middleware<EthExecutionAPI>();
+
+    const web3RequestManager3 = new Web3RequestManager<EthExecutionAPI>('http://localhost:8080', true, middleware3);
+
+    const expectedResponse: JsonRpcResponse<string> = {
+        jsonrpc: '2.0',
+        id: 1,
+        result: '0x0',
+      };
+
+    const mockSendRequest = jest.spyOn(web3RequestManager3 as any, '_sendRequest');
+    mockSendRequest.mockResolvedValue(expectedResponse);
+
+    const request = {
+      id: 1,
+      method: 'eth_call',
+      params: ['0x3'],
+    };
+
+    const response = await web3RequestManager3.send(request);
+    expect(response).toBe('0x6a756e616964');
+
+    expect(mockSendRequest).toHaveBeenCalledWith({
+      ...request,
+      params: [...request.params, '0x0', '0x1'],
+    });
+
+  });
+});

tools/web3-plugin-example/src/custom_rpc_methods.ts

@@ -17,6 +17,7 @@ along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
 import { Web3PluginBase } from 'web3-core';
 // eslint-disable-next-line require-extensions/require-extensions
 import { Web3Context } from './reexported_web3_context';
+import { Web3Middleware } from './middleware';
 
 type CustomRpcApi = {
 	custom_rpc_method: () => string;
@@ -25,7 +26,24 @@ type CustomRpcApi = {
 
 export class CustomRpcMethodsPlugin extends Web3PluginBase<CustomRpcApi> {
 	public pluginNamespace = 'customRpcMethods';
+	public web3Middleware: Web3Middleware<CustomRpcApi> | undefined;
 
+	public constructor(testMiddleware = false){
+		super();
+
+		if(testMiddleware)
+			this.web3Middleware = new Web3Middleware<CustomRpcApi>();
+	}
+
+public link(parentContext: Web3Context): void {
+
+	if(this.web3Middleware)
+		parentContext.requestManager.setMiddleware(this.web3Middleware);
+
+    super.link(parentContext);
+  }
+
+
 	public async customRpcMethod() {
 		return this.requestManager.send({
 			method: 'custom_rpc_method',
@@ -39,6 +57,7 @@ export class CustomRpcMethodsPlugin extends Web3PluginBase<CustomRpcApi> {
 			params: [parameter1, parameter2],
 		});
 	}
+
 }
 
 // Module Augmentation