[Day23] Flutter - Domain Error Handle (part7)

前言

Hi, 我是鱼板伯爵今天要把侦错的功能加上去，教学内容只会撷取片段程序码，建议大家搭配完整程序码来练习。

完整程序码

需准备的知识

[Day15] Flutter - 大海捞针不是办法 ( Dartz )

安装

dartz: ^0.9.2

Domain：Google Failure

我创建了一个错误讯息的类别，如果Google登入出错时会出现GoogleAuthServerFailure，如果你还有FB、Github等的登入你可以往里面一直新增，FirebaseAuthFailure则是处理登入获取使用者资料的错误讯息。

import 'package:equatable/equatable.dart';

abstract class AuthFailure extends Equatable {
  final String message;

  AuthFailure({required this.message});

  @override
  List<Object> get props => [message];
}

class GoogleAuthServerFailure extends AuthFailure {
  GoogleAuthServerFailure({required String message}) : super(message: "");
}

class FirebaseAuthFailure extends AuthFailure {
  FirebaseAuthFailure({required String message}) : super(message: "");
}

修改 Infrastructure Auth

将所有功能都加上AuthFailure，我多新增了一个getUser，这样一来登入完成後可以直接获取使用者资讯。

import 'package:dartz/dartz.dart';
import 'package:google_sign_in/google_sign_in.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:stunning_tribble/domain/auth/auth_failure.dart';

abstract class AuthRepositoryImpl {
  /// Used when the google login button is triggered.
  Future<Either<AuthFailure, Unit>> signInWithGoogle();

  /// Check if you are logged in.
  Future<Either<AuthFailure, Unit>> isSignedIn();

  /// Log out of device.
  Future<Either<AuthFailure, Unit>> signOut();

  /// Get current user info.
  Future<Either<AuthFailure, User>> getUser();
}

class AuthRepository implements AuthRepositoryImpl {
  final FirebaseAuth _firebaseAuth;
  final GoogleSignIn _googleSignIn;

  AuthRepository()
      : _firebaseAuth = FirebaseAuth.instance,
        _googleSignIn = GoogleSignIn();

  @override
  Future<Either<AuthFailure, Unit>> signInWithGoogle() async {
    try {
      final GoogleSignInAccount? googleUser = await _googleSignIn.signIn();
      if (googleUser == null) {
        return left(GoogleAuthServerFailure(message: "Cache User Failure"));
      }
      final GoogleSignInAuthentication googleAuth =
          await googleUser.authentication;
      final AuthCredential credential = GoogleAuthProvider.credential(
        accessToken: googleAuth.accessToken,
        idToken: googleAuth.idToken,
      );
      await _firebaseAuth.signInWithCredential(credential);

      return right(unit);
    } catch (e) {
      return left(GoogleAuthServerFailure(message: "$e"));
    }
  }

  @override
  Future<Either<AuthFailure, Unit>> isSignedIn() async {
    try {
      final User? currentUser = _firebaseAuth.currentUser;
      if (currentUser != null) {
        return right(unit);
      } else {
        return left(FirebaseAuthFailure(message: "Not Logged In"));
      }
    } catch (e) {
      return left(FirebaseAuthFailure(message: "$e"));
    }
  }

  Future<Either<AuthFailure, User>> getUser() async {
    try {
      return right(_firebaseAuth.currentUser);
    } catch (_) {
      return left(FirebaseAuthFailure(message: "Get Current User Failure"));
    }
  }

  @override
  Future<Either<AuthFailure, Unit>> signOut() async {
    try {
      Future.wait([
        _firebaseAuth.signOut(),
        _googleSignIn.signOut(),
      ]);
      return right(unit);
    } catch (e) {
      return left(FirebaseAuthFailure(message: "$e"));
    }
  }
}