feat: simplify API of bootstrapping, connection to MetaMask (#92)

* add MetaMask abstraction, add default start to RLN Instance, expose RLN Contract

* remove console timer

* improve text

* rename to createRLN

* update README, fix tests

* use Provider type

* use provider as it is

README.md

@@ -71,7 +71,16 @@ Browse http://localhost:8080 and open the dev tools console to see the proof bei
 ```js
 import * as rln from "@waku/rln";
 
-const rlnInstance = await rln.create();
+const rlnInstance = await rln.createRLN();
+```
+
+### Starting RLN to listen to a contract
+
+```js
+import * as rln from "@waku/rln";
+
+const rlnInstance = await rln.createRLN();
+await rlnInstance.start(); // will use default Sepolia contract
 ```
 
 #### Generating RLN Membership Credentials
@@ -94,6 +103,17 @@ let credentials = rlnInstance.generateSeededIdentityCredentials(seed);
 rlnInstance.insertMember(credentials.IDCommitment);
 ```
 
+### Registering Membership on a contract
+
+```js
+import * as rln from "@waku/rln";
+
+const rlnInstance = await rln.createRLN();
+await rlnInstance.start(); // will use default Sepolia contract
+
+const membershipInfo = await rlnInstance.contract.registerWithKey(credentials);
+```
+
 ### Generating a Proof
 
 ```js

src/codec.spec.ts

@@ -44,7 +44,7 @@ const EMPTY_PROTO_MESSAGE = {
 
 describe("RLN codec with version 0", () => {
   it("toWire", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);
@@ -85,7 +85,7 @@ describe("RLN codec with version 0", () => {
   });
 
   it("toProtoObj", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);
@@ -128,7 +128,7 @@ describe("RLN codec with version 0", () => {
 
 describe("RLN codec with version 1", () => {
   it("Symmetric, toWire", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);
@@ -175,7 +175,7 @@ describe("RLN codec with version 1", () => {
   });
 
   it("Symmetric, toProtoObj", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);
@@ -221,7 +221,7 @@ describe("RLN codec with version 1", () => {
   });
 
   it("Asymmetric, toWire", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);
@@ -269,7 +269,7 @@ describe("RLN codec with version 1", () => {
   });
 
   it("Asymmetric, toProtoObj", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);
@@ -318,7 +318,7 @@ describe("RLN codec with version 1", () => {
 
 describe("RLN Codec - epoch", () => {
   it("toProtoObj", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);
@@ -374,7 +374,7 @@ describe("RLN codec with version 0 and meta setter", () => {
   };
 
   it("toWire", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);
@@ -422,7 +422,7 @@ describe("RLN codec with version 0 and meta setter", () => {
   });
 
   it("toProtoObj", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const credential = rlnInstance.generateIdentityCredentials();
     const index = 0;
     const payload = new Uint8Array([1, 2, 3, 4, 5]);

src/codec.ts

@@ -44,15 +44,12 @@ export class RLNEncoder implements IEncoder {
 
   private async generateProof(message: IMessage): Promise<IRateLimitProof> {
     const signal = toRLNSignal(this.contentTopic, message);
-
-    console.time("proof_gen_timer");
     const proof = await this.rlnInstance.generateRLNProof(
       signal,
       this.index,
       message.timestamp,
       this.idSecretHash
     );
-    console.timeEnd("proof_gen_timer");
     return proof;
   }
 

src/create.ts

@@ -0,0 +1,9 @@
+import type { RLNInstance } from "./rln.js";
+
+export async function createRLN(): Promise<RLNInstance> {
+  // A dependency graph that contains any wasm must all be imported
+  // asynchronously. This file does the single async import, so
+  // that no one else needs to worry about it again.
+  const rlnModule = await import("./rln.js");
+  return rlnModule.create();
+}

src/index.spec.ts

@@ -4,7 +4,7 @@ import * as rln from "./index.js";
 
 describe("js-rln", () => {
   it("should verify a proof", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
 
     const credential = rlnInstance.generateIdentityCredentials();
 
@@ -59,7 +59,7 @@ describe("js-rln", () => {
     }
   });
   it("should verify a proof with a seeded membership key generation", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const seed = "This is a test seed";
     const credential = rlnInstance.generateSeededIdentityCredential(seed);
 
@@ -115,7 +115,7 @@ describe("js-rln", () => {
   });
 
   it("should generate the same membership key if the same seed is provided", async function () {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const seed = "This is a test seed";
     const memKeys1 = rlnInstance.generateSeededIdentityCredential(seed);
     const memKeys2 = rlnInstance.generateSeededIdentityCredential(seed);

src/index.ts

@@ -4,6 +4,7 @@ import {
   RLN_STORAGE_ABI,
   SEPOLIA_CONTRACT,
 } from "./constants.js";
+import { createRLN } from "./create.js";
 import { Keystore } from "./keystore/index.js";
 import {
   IdentityCredential,
@@ -14,16 +15,8 @@ import {
 import { RLNContract } from "./rln_contract.js";
 import { MerkleRootTracker } from "./root_tracker.js";
 
-// reexport the create function, dynamically imported from rln.ts
-export async function create(): Promise<RLNInstance> {
-  // A dependency graph that contains any wasm must all be imported
-  // asynchronously. This file does the single async import, so
-  // that no one else needs to worry about it again.
-  const rlnModule = await import("./rln.js");
-  return await rlnModule.create();
-}
-
 export {
+  createRLN,
   Keystore,
   RLNInstance,
   IdentityCredential,

src/metamask.ts

@@ -0,0 +1,15 @@
+import { ethers } from "ethers";
+
+export const extractMetaMaskAccount =
+  async (): Promise<ethers.providers.Web3Provider> => {
+    const ethereum = (window as any).ethereum;
+
+    if (!ethereum) {
+      throw Error(
+        "Missing or invalid Ethereum provider. Please install a Web3 wallet such as MetaMask."
+      );
+    }
+
+    await ethereum.request({ method: "eth_requestAccounts" });
+    return new ethers.providers.Web3Provider(ethereum, "any");
+  };

src/rln.ts

@@ -1,10 +1,14 @@
 import type { IRateLimitProof } from "@waku/interfaces";
 import init from "@waku/zerokit-rln-wasm";
 import * as zerokitRLN from "@waku/zerokit-rln-wasm";
+import { ethers } from "ethers";
 
 import { buildBigIntFromUint8Array, writeUIntLE } from "./byte_utils.js";
+import { SEPOLIA_CONTRACT } from "./constants.js";
 import { dateToEpoch, epochIntToBytes } from "./epoch.js";
+import { extractMetaMaskAccount } from "./metamask.js";
 import verificationKey from "./resources/verification_key.js";
+import { RLNContract } from "./rln_contract.js";
 import * as wc from "./witness_calculator.js";
 import { WitnessCalculator } from "./witness_calculator.js";
 
@@ -158,12 +162,39 @@ export function sha256(input: Uint8Array): Uint8Array {
   return zerokitRLN.hash(lenPrefixedData);
 }
 
+type StartRLNOptions = {
+  /**
+   * If not set - will extract MetaMask account and get provider from it.
+   */
+  provider?: ethers.providers.Provider;
+  /**
+   * If not set - will use default SEPOLIA_CONTRACT address.
+   */
+  registryAddress?: string;
+};
+
 export class RLNInstance {
+  private _contract: null | RLNContract = null;
+
   constructor(
     private zkRLN: number,
     private witnessCalculator: WitnessCalculator
   ) {}
 
+  public get contract(): null | RLNContract {
+    return this._contract;
+  }
+
+  public async start(options: StartRLNOptions = {}): Promise<void> {
+    const provider = options.provider || (await extractMetaMaskAccount());
+    const registryAddress = options.registryAddress || SEPOLIA_CONTRACT.address;
+
+    this._contract = await RLNContract.init(this, {
+      registryAddress,
+      provider,
+    });
+  }
+
   generateIdentityCredentials(): IdentityCredential {
     const memKeys = zerokitRLN.generateExtendedMembershipKey(this.zkRLN); // TODO: rename this function in zerokit rln-wasm
     return IdentityCredential.fromBytes(memKeys);

src/rln_contract.spec.ts

@@ -8,7 +8,7 @@ chai.use(spies);
 
 describe("RLN Contract abstraction", () => {
   it("should be able to fetch members from events and store to rln instance", async () => {
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
 
     rlnInstance.insertMember = () => undefined;
     const insertMemberSpy = chai.spy.on(rlnInstance, "insertMember");
@@ -36,7 +36,7 @@ describe("RLN Contract abstraction", () => {
     const mockSignature =
       "0xdeb8a6b00a8e404deb1f52d3aa72ed7f60a2ff4484c737eedaef18a0aacb2dfb4d5d74ac39bb71fa358cf2eb390565a35b026cc6272f2010d4351e17670311c21c";
 
-    const rlnInstance = await rln.create();
+    const rlnInstance = await rln.createRLN();
     const voidSigner = new ethers.VoidSigner(rln.SEPOLIA_CONTRACT.address);
     const rlnContract = new rln.RLNContract(rlnInstance, {
       registryAddress: rln.SEPOLIA_CONTRACT.address,