Firebase提供了一套SDK用于抹平不用平台鉴权的差异性，为了方便使用，将基于firebase_auth、google_sign_in、sign_in_with_apple的依赖封装一套登录统一的功能集成。
鉴权后将会获取idToken，该数据需要传给服务器进行校验。
步骤：
1.定义模块最终返回的数据结构
class FirebaseAuthInfo { String? idToken; String? providerId; FirebaseAuthInfo({this.idToken, this.providerId}); Map toJson() { return {"idToken": idToken, "providerId": providerId}; } }2. 定义工具类，提供login和logout方法
enum LoginType { google, apple, phone, email } class LoginMethod { late LoginType loginType; factory LoginMethod(LoginType loginType) => LoginMethod._(loginType); LoginMethod._(this.loginType) { switch (loginType) { case LoginType.google: break; case LoginType.apple: break; case LoginType.phone: break; case LoginType.email: break; } } Future login() async { switch (loginType) { case LoginType.google: return await _googleSign(); case LoginType.apple: return await _appleSign(); case LoginType.phone: return; case LoginType.email: return; } } void logout() { switch (loginType) { case LoginType.google: _googleOut(); break; case LoginType.apple: break; case LoginType.phone: break; case LoginType.email: break; } } }3. 基于Firebase Email的鉴权方法（该方法调用时，Android和IOS需要配置对应SchemeUrl，通过Applink才能实现）
Future<FirebaseAuthInfo?> verifyEmail(String email, Uri uri) async { if (FirebaseAuth.instance.isSignInWithEmailLink(uri.toString())) { try { final firebaseAuth = await FirebaseAuth.instance .signInWithEmailLink(email: email, emailLink: uri.toString()); var idToken = await firebaseAuth.user?.getIdToken(); return Future.value(FirebaseAuthInfo( idToken: idToken, providerId: firebaseAuth.credential?.providerId)); } catch (error) { print('Error signing in with email link.'); } return null; } else { return null; } }4. 基于Firebase Phone的鉴权方法（验证码条数需要Firebase console中配置）
Future<FirebaseAuthInfo?> phoneSign(String code, String phone) async { Completer<FirebaseAuthInfo?> completer = Completer(); await FirebaseAuth.instance.verifyPhoneNumber( phoneNumber: '$code $phone', verificationCompleted: (PhoneAuthCredential credential) async { final firebaseAuth = await FirebaseAuth.instance.signInWithCredential(credential); var idToken = await firebaseAuth.user?.getIdToken(); if (!completer.isCompleted) { completer.complete(FirebaseAuthInfo( idToken: idToken, providerId: firebaseAuth.credential?.providerId)); } }, verificationFailed: (FirebaseAuthException e) { if (!completer.isCompleted) { completer.complete(null); } }, codeSent: (String verificationId, int? resendToken) {}, codeAutoRetrievalTimeout: (String verificationId) { if (!completer.isCompleted) { completer.complete(null); } }, ); return completer.future; }5. 基于Google Account的鉴权方法（获取账户信息的作用域请查询官方文档），如需要每次登录都可以选择指定的google账号的动作，需要登录前先登出，否则本地有缓存，下次调用将直接复用上一次的账号信息。
void _googleOut() { try { var googleSignIn = GoogleSignIn( scopes: <String>[ 'https://www.googleapis.com/auth/userinfo.email', "https://www.googleapis.com/auth/userinfo.profile" ], ); googleSignIn.signOut(); } catch (e) {} } Future<FirebaseAuthInfo?> _googleSign() async { try { var googleSignIn = GoogleSignIn( scopes: <String>[ 'https://www.googleapis.com/auth/userinfo.email', "https://www.googleapis.com/auth/userinfo.profile" ], ); await googleSignIn.signOut(); var googleAccountInfo = await googleSignIn.signIn(); var googleAuth = await googleAccountInfo?.authentication; if (googleAuth != null) { var firebaseAuth = await FirebaseAuth.instance .signInWithCredential(GoogleAuthProvider.credential( accessToken: googleAuth.accessToken, idToken: googleAuth.idToken, )); var idToken = await firebaseAuth.user?.getIdToken(); return FirebaseAuthInfo( idToken: idToken, providerId: firebaseAuth.credential?.providerId); } else { return Future.value(); } } catch (e) { debugPrint("Auth error !:${e.toString()}"); } return null; } }6. 基于Apple Account的鉴权方法
Future<FirebaseAuthInfo?> _appleSign() async { try { final appleIdCredential = await SignInWithApple.getAppleIDCredential( scopes: [ AppleIDAuthorizationScopes.email, ], ); final oAuthProvider = OAuthProvider('apple.com'); final credential = oAuthProvider.credential( idToken: appleIdCredential.identityToken, accessToken: appleIdCredential.authorizationCode, ); var identify = await FirebaseAuth.instance.signInWithCredential(credential); var idToken = await identify.user?.getIdToken(); return FirebaseAuthInfo(idToken: idToken, providerId: "apple.com"); } catch (e) { debugPrint("Auth error !:${e.toString()}"); } return null; }
