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使用Google登錄和C ++進行身份驗證

通過將Google登錄功能集成到您的應用中,您可以讓用戶使用其Google帳戶向Firebase進行身份驗證。

在你開始之前

  1. 將Firebase添加到您的C ++項目
  2. 在Firebase控制台中啟用Google登錄:
    1. Firebase控制台中,打開“身份驗證”部分。
    2. 登錄方法標籤上,啟用Google登錄方法,然後點擊保存

訪問firebase::auth::Auth

Auth類是所有API調用的網關。
  1. 添加Auth和App頭文件:
    #include "firebase/app.h"
    #include "firebase/auth.h"
    
  2. 在初始化代碼中,創建一個firebase::App類。
    #if defined(__ANDROID__)
      firebase::App* app =
          firebase::App::Create(firebase::AppOptions(), my_jni_env, my_activity);
    #else
      firebase::App* app = firebase::App::Create(firebase::AppOptions());
    #endif  // defined(__ANDROID__)
    
  3. 為您的firebase::App獲取firebase::auth::Auth類。 AppAuth之間存在一對一的映射。
    firebase::auth::Auth* auth = firebase::auth::Auth::GetAuth(app);
    

使用Firebase進行身份驗證

  1. 按照AndroidiOS上的說明獲取Google登錄的ID令牌。
  2. 用戶成功登錄後,將ID令牌交換為Firebase憑證,並使用Firebase憑證與Firebase進行身份驗證:
    firebase::auth::Credential credential =
        firebase::auth::GoogleAuthProvider::GetCredential(google_id_token,
                                                          nullptr);
    firebase::Future<firebase::auth::User*> result =
        auth->SignInWithCredential(credential);
    
  3. 如果您的程序具有定期運行的更新循環(例如,每秒運行30或60次),則可以使用Auth::SignInWithCredentialLastResult
    firebase::Future<firebase::auth::User*> result =
        auth->SignInWithCredentialLastResult();
    if (result.status() == firebase::kFutureStatusComplete) {
      if (result.error() == firebase::auth::kAuthErrorNone) {
        firebase::auth::User* user = *result.result();
        printf("Sign in succeeded for `%s`\n", user->display_name().c_str());
      } else {
        printf("Sign in failed with error '%s'\n", result.error_message());
      }
    }
    
    每次更新檢查一次結果,或者,如果您的程序是事件驅動的,則您可能更願意註冊對Future的回調

在Future上註冊回調

某些程序具有每秒調用30或60次的Update函數。例如,許多遊戲都遵循這種模式。這些程序可以調用LastResult函數以輪詢異步調用。但是,如果程序是事件驅動的,則可能更希望註冊回調函數。將來完成時將調用回調函數。
void OnCreateCallback(const firebase::Future<firebase::auth::User*>& result,
                      void* user_data) {
  // The callback is called when the Future enters the `complete` state.
  assert(result.status() == firebase::kFutureStatusComplete);

  // Use `user_data` to pass-in program context, if you like.
  MyProgramContext* program_context = static_cast<MyProgramContext*>(user_data);

  // Important to handle both success and failure situations.
  if (result.error() == firebase::auth::kAuthErrorNone) {
    firebase::auth::User* user = *result.result();
    printf("Create user succeeded for email %s\n", user->email().c_str());

    // Perform other actions on User, if you like.
    firebase::auth::User::UserProfile profile;
    profile.display_name = program_context->display_name;
    user->UpdateUserProfile(profile);

  } else {
    printf("Created user failed with error '%s'\n", result.error_message());
  }
}

void CreateUser(firebase::auth::Auth* auth) {
  // Callbacks work the same for any firebase::Future.
  firebase::Future<firebase::auth::User*> result =
      auth->CreateUserWithEmailAndPasswordLastResult();

  // `&my_program_context` is passed verbatim to OnCreateCallback().
  result.OnCompletion(OnCreateCallback, &my_program_context);
}
如果願意,回調函數也可以是lambda。
void CreateUserUsingLambda(firebase::auth::Auth* auth) {
  // Callbacks work the same for any firebase::Future.
  firebase::Future<firebase::auth::User*> result =
      auth->CreateUserWithEmailAndPasswordLastResult();

  // The lambda has the same signature as the callback function.
  result.OnCompletion(
      [](const firebase::Future<firebase::auth::User*>& result,
         void* user_data) {
        // `user_data` is the same as &my_program_context, below.
        // Note that we can't capture this value in the [] because std::function
        // is not supported by our minimum compiler spec (which is pre C++11).
        MyProgramContext* program_context =
            static_cast<MyProgramContext*>(user_data);

        // Process create user result...
        (void)program_context;
      },
      &my_program_context);
}

下一步

用戶首次登錄後,將創建一個新的用戶帳戶並將其鏈接到用戶登錄的憑據(即用戶名和密碼,電話號碼或身份驗證提供者信息)。此新帳戶存儲為Firebase項目的一部分,可用於在項目中的每個應用程序中識別用戶,而無論用戶如何登錄。

  • 在您的應用中,您可以從firebase::auth::User對象獲取用戶的基本個人資料信息:

    firebase::auth::User* user = auth->current_user();
    if (user != nullptr) {
      std::string name = user->display_name();
      std::string email = user->email();
      std::string photo_url = user->photo_url();
      // The user's ID, unique to the Firebase project.
      // Do NOT use this value to authenticate with your backend server,
      // if you have one. Use firebase::auth::User::Token() instead.
      std::string uid = user->uid();
    }
    
  • 在Firebase實時數據庫和雲存儲安全規則中,您可以從auth變量中獲取登錄用戶的唯一用戶ID,並使用它來控制用戶可以訪問哪些數據。

通過將身份驗證提供程序憑據鏈接到現有用戶帳戶,可以允許用戶使用多個身份驗證提供程序登錄您的應用程序

要註銷用戶,請調用SignOut()

auth->SignOut();