Moralis wallet authentication using flutter and Parse SDK

dart_moralis_auth.dart

import 'dart:typed_data';
import 'package:parse_server_sdk_flutter/parse_server_sdk.dart';
import 'package:web3dart/crypto.dart';
import 'package:web3dart/web3dart.dart';

final Wallet? wallet = Wallet(); // User wallet should be initialized

authenticate() async {
  if (wallet == null) {
    throw Exception('Wallet is not initialized');
  }
  
  // Address is required for authentication
  final address = wallet.privateKey.address;

  // Grabbing Moralis servicer time
  final getServerTime = ParseCloudFunction('getServerTime');
  final serverTimeResponse = await getServerTime.execute();
  final serverTime = Map<String, dynamic>.from(serverTimeResponse.result)['dateTime'];
  
  // Grabbing Moralis Application ID, should be provided in Parse().initialize()
  final appId = ParseCoreData().applicationId;
  
  // Defining your signing message
  final anyMessageToSign = "Welcome to my awesome DApp";
  final data = "$anyMessageToSign\n\nId: $appId:$serverTime";

  // Using web3dart .signPersonalMessage(...) to sign the message
  // this methood retuns a EIP-191 compliant signeture as ethersJs .signMessage(...)
  // Check https://docs.ethers.io/v5/api/signer/#Signer-signMessage
  final signedMessage = await wallet.privateKey
      .signPersonalMessage(Uint8List.fromList(data.codeUnits));
  final signature = bytesToHex(signedMessage, include0x: true);
  // Composing the payload moralis expect
  final authData = {
    "id": address!.hex,
    "signature": signature,
    "data": data,
  };
  // Logging with moralis custom authentication
  final response = await ParseUser.loginWith("moralisEth", authData);

  // In case of errors you can check the `response`
  if (!response.success) {
    throw Exception('Authentication failed');
  }

  // According to ParsePlatform docs in case loginWith was a success ParseUser.currentUser()
  // Will hold the authenticated user
  final user = ParseUser.currentUser() as ParseObject;

  // Setting up the user in case of registration as Moralis JS SDK does
  user.setACL(user);
  user.setAddAllUnique('accounts', [address.hex]);
  user.set('ethAddress', address.hex);
  await user.save();
  return user;
}

Good gist it helped out!