feat: setting up base paymaster and pimlico paymaster

src/gasless-provider.ts

@@ -4,10 +4,11 @@
 import init from 'debug';
 import { createPublicClient, concat, encodeFunctionData, Hex } from 'viem';
 import { privateKeyToAccount } from 'viem/accounts';
 import { PimlicoBundlerClient, PimlicoPaymasterClient } from 'permissionless/clients/pimlico';
 import { UserOperation } from 'permissionless/types';
 import { getSenderAddress, signUserOperationHashWithECDSA } from 'permissionless';
 import * as constants from '../src/constants';
+import { BasePaymaster } from './paymasters';
 
 const log = init('hardhat:plugin:gasless');
 
@@ -21,7 +22,7 @@
     protected readonly _wrappedProvider: EIP1193Provider,
     public readonly chain: string,
     protected readonly bundlerClient: PimlicoBundlerClient,
-    protected readonly paymasterClient: PimlicoPaymasterClient,
+    protected readonly paymasterClient: BasePaymaster,
     protected readonly publicClient: ReturnType<typeof createPublicClient>,
     protected readonly _initCode: `0x${string}`,
     protected readonly senderAddress: `0x${string}`,
@@ -38,7 +39,7 @@
     _wrappedProvider: EIP1193Provider,
     chain: string,
     bundlerClient: PimlicoBundlerClient,
-    paymasterClient: PimlicoPaymasterClient,
+    paymasterClient: BasePaymaster,
     publicClient: ReturnType<typeof createPublicClient>,
   ) {
     // NOTE: Bundlers can support many entry points, but currently they only support one, we use this method so if they ever add a new one the entry point will still work
@@ -136,10 +137,7 @@
     };
 
     // REQUEST PIMLICO VERIFYING PAYMASTER SPONSORSHIP
-    const sponsorUserOperationResult = await this.paymasterClient.sponsorUserOperation({
-      userOperation,
-      entryPoint: this._entryPoint,
-    });
+    const sponsorUserOperationResult = await this.paymasterClient.sponsorUserOperation(userOperation, this._entryPoint);
 
     const sponsoredUserOperation: UserOperation = {
       ...userOperation,

src/index.ts

@@ -1,6 +1,7 @@
 import { extendProvider } from 'hardhat/config';
 import { createPublicClient, http } from 'viem';
-import { createPimlicoPaymasterClient, createPimlicoBundlerClient } from 'permissionless/clients/pimlico';
+import { createPimlicoBundlerClient } from 'permissionless/clients/pimlico';
+import { createPaymasterClient } from './paymaster';
 
 import 'dotenv/config';
 
@@ -10,6 +11,7 @@ const log = init('hardhat:plugin:gasless');
 
 import './type-extensions';
 import { GaslessProvider } from './gasless-provider';
+import { PaymasterType } from './types';
 
 // NOTE: Network name has to match how pimlico names the network in their API calls
 extendProvider(async (provider, config, networkName) => {
@@ -42,9 +44,11 @@ extendProvider(async (provider, config, networkName) => {
     transport: http(sponsoredTransaction.bundlerUrl),
   });
 
-  const paymasterClient = createPimlicoPaymasterClient({
-    transport: http(sponsoredTransaction.paymasterUrl),
-  });
+  // TODO: Change this to use our Paymaster classes based on the paymasterType
+  const paymasterClient = createPaymasterClient(
+    sponsoredTransaction.paymasterType as PaymasterType,
+    sponsoredTransaction.paymasterUrl,
+  );
 
   return await GaslessProvider.create(signer, provider, networkName, bundlerClient, paymasterClient, publicClient);
 });

src/paymaster.ts

@@ -0,0 +1,13 @@
+import { PaymasterType } from './types';
+import { BasePaymaster } from './paymasters/BasePaymaster';
+import * as Pm from './paymasters';
+
+export function createPaymasterClient(paymasterType: PaymasterType, paymasterUrl: string): BasePaymaster {
+  switch (paymasterType) {
+    case PaymasterType.Pimlico:
+      return new Pm.PimlicoPaymaster(paymasterUrl);
+
+    default:
+      throw new Error(`Unknown paymaster type ${paymasterType}`);
+  }
+}

src/paymasters/BasePaymaster.ts

@@ -0,0 +1,13 @@
+import { PartialUserOperation } from '../types';
+
+export class BasePaymaster {
+  public endpoint: string;
+
+  constructor(endpoint: string) {
+    this.endpoint = endpoint;
+  }
+
+  public async sponsorUserOperation(userOp: PartialUserOperation, entryPoint: `0x${string}`): Promise<any> {
+    throw new Error('This is a base class and should not be called directly.');
+  }
+}

src/paymasters/PimlicoPaymaster.ts

@@ -0,0 +1,26 @@
+import { BasePaymaster } from './BasePaymaster';
+import { PartialUserOperation } from '../types';
+import { http } from 'viem';
+import { createPimlicoPaymasterClient } from 'permissionless/clients/pimlico';
+import { SponsorUserOperationReturnType } from 'permissionless/actions/pimlico';
+
+export class PimlicoPaymaster extends BasePaymaster {
+  public paymasterClient: ReturnType<typeof createPimlicoPaymasterClient>;
+
+  constructor(endpoint: string) {
+    super(endpoint);
+    this.paymasterClient = createPimlicoPaymasterClient({
+      transport: http(endpoint),
+    });
+  }
+
+  public async sponsorUserOperation(
+    userOperation: PartialUserOperation,
+    entryPoint: `0x${string}`,
+  ): Promise<SponsorUserOperationReturnType> {
+    return await this.paymasterClient.sponsorUserOperation({
+      userOperation,
+      entryPoint,
+    });
+  }
+}

src/paymasters/index.ts

@@ -0,0 +1,2 @@
+export * from './BasePaymaster';
+export * from './PimlicoPaymaster';

src/type-extensions.ts

@@ -1,18 +1,21 @@
 import 'hardhat/types/config';
 import 'hardhat/types/runtime';
+import { PaymasterTypeLiteral } from './types';
 
 declare module 'hardhat/types/config' {
   export interface HttpNetworkUserConfig {
     sponsoredTransaction?: {
       bundlerUrl: string;
       paymasterUrl: string;
+      paymasterType: PaymasterTypeLiteral;
     };
   }
 
   export interface HttpNetworkConfig {
     sponsoredTransaction?: {
       bundlerUrl: string;
       paymasterUrl: string;
+      paymasterType: PaymasterTypeLiteral;
     };
   }
 }

src/types.ts

@@ -0,0 +1,18 @@
+export type PartialUserOperation = {
+  sender: `0x${string}`;
+  nonce: bigint;
+  initCode: `0x${string}`;
+  callData: `0x${string}`;
+  maxFeePerGas: bigint;
+  maxPriorityFeePerGas: bigint;
+  signature: `0x${string}`;
+};
+
+export enum PaymasterType {
+  Pimlico = 'pimlico',
+  Biconomy = 'biconomy',
+}
+
+export type PaymasterTypeLiteral = keyof {
+  [K in keyof typeof PaymasterType as string]: K;
+};

test/fixture-projects/hardhat-project/hardhat.config.ts

@@ -11,6 +11,7 @@ const config: HardhatUserConfig = {
       sponsoredTransaction: {
         bundlerUrl: 'http://localhost:3000',
         paymasterUrl: 'http://localhost:3001',
+        paymasterType: 'pimlico',
       },
     },
   },