Flutter & firebase auth(google, apple, email login) 사용하기

Setting

Google Login

• Firebase에서 안드로이드 앱을 등록할때 반드시 SHA 인증서 지문을 입력해줘야한다.

    keytool -list -v \
    -alias androiddebugkey -keystore ~/.android/debug.keystore
  

  • 비밀번호는 반드시 android로 한다

    // flutter pub add google_sign_in.dart
      
    import 'package:google_sign_in/google_sign_in.dart';
      
    Future<UserCredential> signInWithGoogle() async {
    	try {
    	  // Trigger the authentication flow
    	  final GoogleSignInAccount? googleUser = await GoogleSignIn().signIn();
      	
    	  // Obtain the auth details from the request
    	  final GoogleSignInAuthentication googleAuth =
    	      await googleUser!.authentication;
      	
    	  // Create a new credential
    	  final credential = GoogleAuthProvider.credential(
    	    accessToken: googleAuth.accessToken,
    	    idToken: googleAuth.idToken,
    	  );
      	
    	  // Once signed in, return the UserCredential
    	  return await FirebaseAuth.instance.signInWithCredential(credential);
    	} catch (e) {
    		print(e);
    	}
    }
  

• 구글 로그인의 경우 예외처리를 해줘도 PlatformExption이 발생하는데, reales 버전에서는 문제 없다고 한다…

Apple Login

• 사전준비
  1. Firebase에서 앱을 추가할때 Apple Developer에서 발급받은 앱 ID가 필요
     • Apple Developer → Certificates → identifiers → 생성
     • App IDs → App → Sign In with Apple 체크 후 등록
  2. Xcode Runner → Signing & Capabilities → + Capability → Sign in with Apple
  3. GoogleService-Info.plist에서 REVERSED_CLIENT_ID 값을 Runner → Info → URL Types 추가 후 URL Schemes에 입력
• 필요조건

  1. iOS 13 이상 : Signing with Apple

      // flutter pub add sign_in_with_apple
             
      import 'package:sign_in_with_apple/sign_in_with_apple.dart';
      import 'dart:math';
      import 'dart:convert';
             
      String generateNonce([int length = 32]) {
        final charset =
            '0123456789ABCDEFGHIJKLMNOPQRSTUVXYZabcdefghijklmnopqrstuvwxyz-._';
        final random = Random.secure();
        return List.generate(length, (_) => charset[random.nextInt(charset.length)])
            .join();
      }
             
      /// Returns the sha256 hash of [input] in hex notation.
      String sha256ofString(String input) {
        final bytes = utf8.encode(input);
        final digest = sha256.convert(bytes);
        return digest.toString();
      }
             
      Future<UserCredential> signInWithApple() async {
      	try {
      	  // Request credential for the currently signed in Apple account.
      	  final appleCredential = await SignInWithApple.getAppleIDCredential(
      	    scopes: [
      	      AppleIDAuthorizationScopes.email,
      	      AppleIDAuthorizationScopes.fullName,
      	    ],
      	  );
             	
      	  // Create an `OAuthCredential` from the credential returned by Apple.
      	  final oauthCredential = OAuthProvider("apple.com").credential(
      	    idToken: appleCredential.identityToken,
      	    accessToken: appleCredential.authorizationCode,
      	  );
             	
      	  // Sign in the user with Firebase. If the nonce we generated earlier does
      	  // not match the nonce in `appleCredential.identityToken`, sign in will fail.
      	  return await FirebaseAuth.instance.signInWithCredential(oauthCredential);
      	} catch (e) {
      		// 로그인을 취소했을 경우
      		print(e);
      	}
      }
     

Email Login

void _emailSignUp() async {
    try {
      UserCredential userCredential = await FirebaseAuth.instance
          .createUserWithEmailAndPassword(
              email: "myemail@google.com", password: "SuperSecretPassword!");
    } on FirebaseAuthException catch (e) {
      if (e.code == 'weak-password') {
        print('The password provided is too weak.');
      } else if (e.code == 'email-already-in-use') {
        print('The account already exists for that email.');
      }
    } catch (e) {
      print(e);
    }
  }

  void _emailSignIn() async {
    try {
      // UserCredential userCredential =
      await FirebaseAuth.instance.signInWithEmailAndPassword(
          email: "myemail@google.com", password: "SuperSecretPassword!");
    } on FirebaseAuthException catch (e) {
      if (e.code == 'user-not-found') {
        print('No user found for that email.');
      } else if (e.code == 'wrong-password') {
        print('Wrong password provided for that user.');
      }
    }
  }

Use

StreamBuilder로 상태 가져오기

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<User?>(
      stream: FirebaseAuth.instance.authStateChanges(),
      builder: (BuildContext context, AsyncSnapshot<User?> user) {
        if (!user.hasData) {
          // 로그인한적이 없는 경우
          return SignIn();
        }

        // 로그인한 경우
        return MyPage();
      },
    );
  }
}

정보가져오기

• FirebaseAuth.instance.currentUser!.
  • photoURL
  • displayName : google에서 따로 지정하지 않으면 null
  • email
  • emailVerified
  • metadata
    • creationTime
    • lastSignInTime
  • uid

동작하기

• 이메일 인증 메일 보내기 FirebaseAuth.instance.currentUser!.sendEmailVerification();
• 로그아웃 FirebaseAuth.instance.signOut();
• 유저 삭제 FirebaseAuth.instance.currentUser!.delete();
• 비밀번호 재설정 FirebaseAuth.instance.sendPasswordResetEmail(email: "email@example.com")