使用 Firebase Admin SDK 傳送訊息

如果尚未設定 Firebase Admin SDK，請按照指南在伺服器上設定 Firebase Admin SDK。

啟用 FCM HTTP v1 API

  1. 在 Firebase 控制台中，依序前往「設定」 >「一般」。然後按一下「Cloud Messaging」分頁標籤。

  2. 啟用 Cloud Messaging API。

授權其他專案的服務帳戶

您可以使用「傳送者專案」中的服務帳戶，為「目標專案」傳送訊息。這樣一來，您就能在一個專案中集中管理服務帳戶，同時代表他人傳送訊息。如要瞭解如何執行這項操作，請按照下列步驟操作：

  1. 在傳送者專案中，請確認已啟用 Firebase Cloud Messaging API。如要檢查是否已啟用，請前往 Firebase 控制台，然後依序點選「設定」「一般」。然後按一下「Cloud Messaging」分頁標籤。

  2. 在傳送者專案中，建立服務帳戶。

  3. 在目標專案中，將 Firebase Cloud Messaging API 管理員角色指派給服務帳戶的電子郵件地址。您可以在 Google Cloud 控制台的「IAM & Admin」(IAM 與管理) >「IAM」(身分與存取權管理)頁面執行這項操作。這個角色可讓傳送端專案的服務帳戶將訊息傳送至目標專案。

  4. 使用傳送者專案的服務帳戶金鑰檔案和目標專案的專案 ID，初始化 SDK。

    Node.js

    import { initializeApp, applicationDefault } from 'firebase-admin/app';

initializeApp({
  // The credential is configured to be the sender project's service
  // account key via the environment variable GOOGLE_APPLICATION_CREDENTIALS
  credential: applicationDefault(),
  projectId: '<TARGET_PROJECT_ID>',
});

    Java

    FirebaseOptions options = FirebaseOptions.builder()
    // The credential is configured to be the sender project's service
    // account key via the environment variable GOOGLE_APPLICATION_CREDENTIALS
    .setCredentials(GoogleCredentials.getApplicationDefault())
    .setProjectId("<TARGET_PROJECT_ID>")
    .build();

FirebaseApp.initializeApp(options);

    Python

    import firebase_admin

app_options = {'projectId': '<TARGET_PROJECT_ID>'}
# Initialize with the default credential, i.e. the sender project's service
# account key, stored in GOOGLE_APPLICATION_CREDENTIALS
default_app = firebase_admin.initialize_app(options=app_options)

    Go

    config := &firebase.Config{ProjectID: "<TARGET_PROJECT_ID>"}
// Initialize with the default credential, i.e. the sender project's service
// account key, stored in GOOGLE_APPLICATION_CREDENTIALS
app, err := firebase.NewApp(context.Background(), config)
if err != nil {
        log.Fatalf("error initializing app: %v\n", err)
}

    C#

    FirebaseApp.Create(new AppOptions()
{
    // The credential is configured to be the sender project's service
    // account key via the environment variable GOOGLE_APPLICATION_CREDENTIALS
    Credential = GoogleCredential.GetApplicationDefault(),
    ProjectId = "<TARGET_PROJECT_ID>",
});

將訊息傳送至特定裝置

如要傳送至特定單一裝置，可以指定該裝置的 Firebase 安裝 ID (FID) 或註冊權杖。

Node.js

使用 FID (建議)：

// This installation ID comes from the client FCM SDKs.
const fid = 'YOUR_REGISTERED_FID';

const message = {
  data: {
    score: '850',
    time: '2:45'
  },
  fid: fid
};

// Send a message to the device corresponding to the provided FID.
getMessaging().send(message)
  .then((response) => {
    // Response is a message ID string.
    console.log('Successfully sent message:', response);
  })
  .catch((error) => {
    console.log('Error sending message:', error);
  });

使用註冊權杖 (已淘汰)：

// This registration token comes from the client FCM SDKs.
const registrationToken = 'YOUR_REGISTRATION_TOKEN';

const message = {
  data: {
    score: '850',
    time: '2:45'
  },
  token: registrationToken
};

// Send a message to the device corresponding to the provided
// registration token.
getMessaging().send(message)
  .then((response) => {
    // Response is a message ID string.
    console.log('Successfully sent message:', response);
  })
  .catch((error) => {
    console.log('Error sending message:', error);
  });

Java

使用 FID (建議)：

// This installation ID comes from the client FCM SDKs.
String fid = "YOUR_REGISTERED_FID";

// See documentation on defining a message payload.
Message message = Message.builder()
    .putData("score", "850")
    .putData("time", "2:45")
    .setFid(fid)
    .build();

// Send a message to the device corresponding to the provided FID.
String response = FirebaseMessaging.getInstance().send(message);
// Response is a message ID string.
System.out.println("Successfully sent message: " + response);

使用註冊權杖 (已淘汰)：

// This registration token comes from the client FCM SDKs.
String registrationToken = "YOUR_REGISTRATION_TOKEN";

// See documentation on defining a message payload.
Message message = Message.builder()
    .putData("score", "850")
    .putData("time", "2:45")
    .setToken(registrationToken)
    .build();

// Send a message to the device corresponding to the provided
// registration token.
String response = FirebaseMessaging.getInstance().send(message);
// Response is a message ID string.
System.out.println("Successfully sent message: " + response);

Python

使用 FID (建議)：

# This installation ID comes from the client FCM SDKs.
fid = 'YOUR_REGISTERED_FID'

# See documentation on defining a message payload.
message = messaging.Message(
    data={
        'score': '850',
        'time': '2:45',
    },
    fid=fid,
)

# Send a message to the device corresponding to the provided FID.
response = messaging.send(message)
# Response is a message ID string.
print('Successfully sent message:', response)

使用註冊權杖 (已淘汰)：

# This registration token comes from the client FCM SDKs.
registration_token = 'YOUR_REGISTRATION_TOKEN'

# See documentation on defining a message payload.
message = messaging.Message(
    data={
        'score': '850',
        'time': '2:45',
    },
    token=registration_token,
)

# Send a message to the device corresponding to the provided
# registration token.
response = messaging.send(message)
# Response is a message ID string.
print('Successfully sent message:', response)

Go

使用 FID (建議)：

// Obtain a messaging.Client from the App.
ctx := context.Background()
client, err := app.Messaging(ctx)
if err != nil {
    log.Fatalf("error getting Messaging client: %v\n", err)
}

// This installation ID comes from the client FCM SDKs.
fid := "YOUR_REGISTERED_FID"

// See documentation on defining a message payload.
message := &messaging.Message{
    Data: map[string]string{
        "score": "850",
        "time":  "2:45",
    },
    Fid: fid,
}

// Send a message to the device corresponding to the provided FID.
response, err := client.Send(ctx, message)
if err != nil {
    log.Fatalln(err)
}
// Response is a message ID string.
fmt.Println("Successfully sent message:", response)

使用註冊權杖 (已淘汰)：

// Obtain a messaging.Client from the App.
ctx := context.Background()
client, err := app.Messaging(ctx)
if err != nil {
	log.Fatalf("error getting Messaging client: %v\n", err)
}

// This registration token comes from the client FCM SDKs.
registrationToken := "YOUR_REGISTRATION_TOKEN"

// See documentation on defining a message payload.
message := &messaging.Message{
	Data: map[string]string{
		"score": "850",
		"time":  "2:45",
	},
	Token: registrationToken,
}

// Send a message to the device corresponding to the provided
// registration token.
response, err := client.Send(ctx, message)
if err != nil {
	log.Fatalln(err)
}
// Response is a message ID string.
fmt.Println("Successfully sent message:", response)

C#

使用 FID (建議)：

// This installation ID comes from the client FCM SDKs.
var fid = "YOUR_REGISTERED_FID";

var message = new Message()
{
    Data = new Dictionary<string, string>()
    {
        { "score", "850" },
        { "time", "2:45" },
    },
    Fid = fid,
};

// Send a message to the device corresponding to the provided FID.
string response = await FirebaseMessaging.DefaultInstance.SendAsync(message);
// Response is a message ID string.
Console.WriteLine("Successfully sent message: " + response);

使用註冊權杖 (已淘汰)：

            // This registration token comes from the client FCM SDKs.
            var registrationToken = "YOUR_REGISTRATION_TOKEN";

            // See documentation on defining a message payload.
            var message = new Message()
            {
                Data = new Dictionary<string, string>()
                {
                    { "score", "850" },
                    { "time", "2:45" },
                },
#pragma warning disable CS0618
                Token = registrationToken,
#pragma warning restore CS0618
            };

            // Send a message to the device corresponding to the provided
            // registration token.
            string response = await FirebaseMessaging.DefaultInstance.SendAsync(message);
            // Response is a message ID string.
            Console.WriteLine("Successfully sent message: " + response);

成功時，每個傳送方法都會傳回郵件 ID。Firebase Admin SDK 會傳回 projects/{project_id}/messages/{message_id} 格式的 ID 字串。

將訊息傳送至多部裝置

您可以使用 Admin FCM SDK，將訊息多播至 Firebase 安裝 ID (FID) 或裝置註冊權杖清單。如需將相同訊息傳送至大量裝置，可以使用這項功能。每次呼叫最多可指定 500 個 FID 和/或權杖。

傳回值包含與輸入目標、FID 和/或權杖順序對應的回覆清單。如要查看哪些目標導致錯誤，這項功能就非常實用。如果同時提供權杖和 FID，系統會先處理權杖，再處理 FID。

Node.js

使用 FID (建議)：

// These Firebase Installation IDs (FIDs) come from the client FCM SDKs.
const fids = [
  'YOUR_REGISTERED_FID_1',
  // ...
  'YOUR_REGISTERED_FID_N'
];

const message = {
  data: {score: '850', time: '2:45'},
  fids: fids,
};

getMessaging().sendEachForMulticast(message)
  .then((response) => {
    console.log(response.successCount + ' messages were sent successfully');
    if (response.failureCount > 0) {
      const failedFids = [];
      response.responses.forEach((resp, idx) => {
        if (!resp.success) {
          failedFids.push(fids[idx]);
        }
      });
      console.log('List of FIDs that caused failures: ' + failedFids);
    }
  });

使用註冊權杖 (已淘汰)：

// These registration tokens come from the client FCM SDKs.
const registrationTokens = [
  'YOUR_REGISTRATION_TOKEN_1',
  // …
  'YOUR_REGISTRATION_TOKEN_N',
];

const message = {
  data: {score: '850', time: '2:45'},
  tokens: registrationTokens,
};

getMessaging().sendEachForMulticast(message)
  .then((response) => {
    if (response.failureCount > 0) {
      const failedTokens = [];
      response.responses.forEach((resp, idx) => {
        if (!resp.success) {
          failedTokens.push(registrationTokens[idx]);
        }
      });
      console.log('List of tokens that caused failures: ' + failedTokens);
    }
  });

Java

使用 FID (建議)：

// These Firebase Installation IDs (FIDs) come from the client FCM SDKs.
List<String> fids = Arrays.asList(
    "YOUR_REGISTERED_FID_1",
    // ...
    "YOUR_REGISTERED_FID_N"
);

MulticastMessage message = MulticastMessage.builder()
    .putData("score", "850")
    .putData("time", "2:45")
    .addAllFids(fids)
    .build();

BatchResponse response = FirebaseMessaging.getInstance().sendEachForMulticast(message);
if (response.getFailureCount() > 0) {
  List<SendResponse> responses = response.getResponses();
  List<String> failedFids = new ArrayList<>();
  for (int i = 0; i < responses.size(); i++) {
    if (!responses.get(i).isSuccessful()) {
      // The order of responses corresponds to the order of the destination FIDs.
      failedFids.add(fids.get(i));
    }
  }
  System.out.println("List of FIDs that caused failures: " + failedFids);
}

使用註冊權杖 (已淘汰)：

// These registration tokens come from the client FCM SDKs.
List<String> registrationTokens = Arrays.asList(
    "YOUR_REGISTRATION_TOKEN_1",
    // ...
    "YOUR_REGISTRATION_TOKEN_n"
);

MulticastMessage message = MulticastMessage.builder()
    .putData("score", "850")
    .putData("time", "2:45")
    .addAllTokens(registrationTokens)
    .build();
BatchResponse response = FirebaseMessaging.getInstance().sendEachForMulticast(message);
if (response.getFailureCount() > 0) {
  List<SendResponse> responses = response.getResponses();
  List<String> failedTokens = new ArrayList<>();
  for (int i = 0; i < responses.size(); i++) {
    if (!responses.get(i).isSuccessful()) {
      // The order of responses corresponds to the order of the registration tokens.
      failedTokens.add(registrationTokens.get(i));
    }
  }

  System.out.println("List of tokens that caused failures: " + failedTokens);
}

Python

使用 FID (建議)：

# These Firebase Installation IDs (FIDs) come from the client FCM SDKs.
fids = [
    'YOUR_REGISTERED_FID_1',
    # ...
    'YOUR_REGISTERED_FID_N',
]

message = messaging.MulticastMessage(
    data={'score': '850', 'time': '2:45'},
    fids=fids,
)
response = messaging.send_each_for_multicast(message)
if response.failure_count > 0:
    responses = response.responses
    failed_fids = []
    for idx, resp in enumerate(responses):
        if not resp.success:
            # The order of responses corresponds to the order of the destination FIDs.
            failed_fids.append(fids[idx])
    print('List of FIDs that caused failures: {0}'.format(failed_fids))

使用註冊權杖 (已淘汰)：

# These registration tokens come from the client FCM SDKs.
registration_tokens = [
    'YOUR_REGISTRATION_TOKEN_1',
    # ...
    'YOUR_REGISTRATION_TOKEN_N',
]

message = messaging.MulticastMessage(
    data={'score': '850', 'time': '2:45'},
    tokens=registration_tokens,
)
response = messaging.send_each_for_multicast(message)
if response.failure_count > 0:
    responses = response.responses
    failed_tokens = []
    for idx, resp in enumerate(responses):
        if not resp.success:
            # The order of responses corresponds to the order of the registration tokens.
            failed_tokens.append(registration_tokens[idx])
    print(f'List of tokens that caused failures: {failed_tokens}')

Go

使用 FID (建議)：

// Create a list containing up to 500 Firebase Installation IDs (FIDs).
// These Firebase Installation IDs (FIDs) come from the client FCM SDKs.
fids := []string{
    "YOUR_REGISTERED_FID_1",
    // ...
    "YOUR_REGISTERED_FID_N",
}

message := &messaging.MulticastMessage{
    Data: map[string]string{
        "score": "850",
        "time":  "2:45",
    },
    Fids: fids,
}

br, err := client.SendEachForMulticast(ctx, message)
if err != nil {
    log.Fatalln(err)
}

if br.FailureCount > 0 {
    var failedFids []string
    for idx, resp := range br.Responses {
        if !resp.Success {
            // The order of responses corresponds to the order of the destination FIDs.
            failedFids = append(failedFids, fids[idx])
        }
    }
    fmt.Printf("List of FIDs that caused failures: %v\n", failedFids)
}

使用註冊權杖 (已淘汰)：

// Create a list containing up to 500 registration tokens.
// This registration tokens come from the client FCM SDKs.
registrationTokens := []string{
	"YOUR_REGISTRATION_TOKEN_1",
	// ...
	"YOUR_REGISTRATION_TOKEN_n",
}
message := &messaging.MulticastMessage{
	Data: map[string]string{
		"score": "850",
		"time":  "2:45",
	},
	Tokens: registrationTokens,
}

br, err := client.SendEachForMulticast(context.Background(), message)
if err != nil {
	log.Fatalln(err)
}

if br.FailureCount > 0 {
	var failedTokens []string
	for idx, resp := range br.Responses {
		if !resp.Success {
			// The order of responses corresponds to the order of the registration tokens.
			failedTokens = append(failedTokens, registrationTokens[idx])
		}
	}

	fmt.Printf("List of tokens that caused failures: %v\n", failedTokens)
}

C#

使用 FID (建議)：

// These Firebase Installation IDs (FIDs) come from the client FCM SDKs.
var fids = new List<string>()
{
    "YOUR_REGISTERED_FID_1",
    // ...
    "YOUR_REGISTERED_FID_N",
};

var message = new MulticastMessage()
{
    Data = new Dictionary<string, string>()
    {
        { "score", "850" },
        { "time", "2:45" },
    },
    Fids = fids,
};

var response = await FirebaseMessaging.DefaultInstance.SendEachForMulticastAsync(message);

if (response.FailureCount > 0)
{
    var failedFids = new List<string>();
    for (var i = 0; i < response.Responses.Count; i++)
    {
        if (!response.Responses[i].IsSuccess)
        {
            // The order of responses corresponds to the order of the destination FIDs.
            failedFids.add(fids[i]);
        }
    }
    Console.WriteLine($"List of FIDs that caused failures: {string.Join(", ", failedFids)}");
}

使用註冊權杖 (已淘汰)：

            // These registration tokens come from the client FCM SDKs.
            var registrationTokens = new List<string>()
            {
                "YOUR_REGISTRATION_TOKEN_1",
                // ...
                "YOUR_REGISTRATION_TOKEN_n",
            };
            var message = new MulticastMessage()
            {
#pragma warning disable CS0618
                Tokens = registrationTokens,
#pragma warning restore CS0618
                Data = new Dictionary<string, string>()
                {
                    { "score", "850" },
                    { "time", "2:45" },
                },
            };

            var response = await FirebaseMessaging.DefaultInstance.SendEachForMulticastAsync(message);
            if (response.FailureCount > 0)
            {
                var failedTokens = new List<string>();
                for (var i = 0; i < response.Responses.Count; i++)
                {
                    if (!response.Responses[i].IsSuccess)
                    {
                        // The order of responses corresponds to the order of the registration tokens.
                        failedTokens.Add(registrationTokens[i]);
                    }
                }

                Console.WriteLine($"List of tokens that caused failures: {failedTokens}");
            }

傳送訊息清單

Admin SDK 最多可傳送 500 則訊息。這項功能可用於建立自訂訊息集，並傳送給不同收件者，包括主題、Firebase 安裝 ID (FID) 或裝置註冊權杖。舉例來說，如果需要向不同目標對象傳送不同訊息，就可以使用這項功能。

Node.js

使用混合目標 (建議做法)：

// Create a list containing up to 500 messages.
const messages = [
  {
    notification: { title: 'Price drop', body: '5% off all electronics' },
    fid: 'YOUR_REGISTERED_FID', // Using FID (Recommended)
  },
  {
    notification: { title: 'Price drop', body: '2% off all books' },
    token: 'YOUR_REGISTRATION_TOKEN', // Using token (Deprecated)
  },
  {
    notification: { title: 'Price drop', body: '10% off all shoes' },
    topic: 'readers-club',
  }
];

getMessaging().sendEach(messages)
  .then((response) => {
    console.log(response.successCount + ' messages were sent successfully');
  });

使用註冊權杖 (已淘汰)：

// Create a list containing up to 500 messages.
const messages = [];
messages.push({
  notification: { title: 'Price drop', body: '5% off all electronics' },
  token: registrationToken,
});
messages.push({
  notification: { title: 'Price drop', body: '2% off all books' },
  topic: 'readers-club',
});

getMessaging().sendEach(messages)
  .then((response) => {
    console.log(response.successCount + ' messages were sent successfully');
  });

Java

使用混合目標 (建議做法)：

// Create a list containing up to 500 messages.
List<Message> messages = new ArrayList<>();
messages.add(Message.builder()
    .setNotification(Notification.builder()
        .setTitle("Price drop")
        .setBody("5% off all electronics")
        .build())
    .setFid("YOUR_REGISTERED_FID") // Using FID (Recommended)
    .build());
messages.add(Message.builder()
    .setNotification(Notification.builder()
        .setTitle("Price drop")
        .setBody("2% off all books")
        .build())
    .setToken("YOUR_REGISTRATION_TOKEN") // Using token (Deprecated)
    .build());
messages.add(Message.builder()
    .setNotification(Notification.builder()
        .setTitle("Price drop")
        .setBody("10% off all shoes")
        .build())
    .setTopic("readers-club")
    .build());

BatchResponse response = FirebaseMessaging.getInstance().sendEach(messages);
// See the BatchResponse reference documentation
// for the contents of response.
System.out.println(response.getSuccessCount() + " messages were sent successfully");

使用註冊權杖 (已淘汰)：

// Create a list containing up to 500 messages.
List<Message> messages = Arrays.asList(
    Message.builder()
        .setNotification(Notification.builder()
            .setTitle("Price drop")
            .setBody("5% off all electronics")
            .build())
        .setToken(registrationToken)
        .build(),
    // ...
    Message.builder()
        .setNotification(Notification.builder()
            .setTitle("Price drop")
            .setBody("2% off all books")
            .build())
        .setTopic("readers-club")
        .build()
);

BatchResponse response = FirebaseMessaging.getInstance().sendEach(messages);
// See the BatchResponse reference documentation
// for the contents of response.
System.out.println(response.getSuccessCount() + " messages were sent successfully");

Python

使用混合目標 (建議做法)：

# Create a list containing up to 500 messages.
messages = [
    messaging.Message(
        notification=messaging.Notification('Price drop', '5% off all electronics'),
        fid='YOUR_REGISTERED_FID', # Using FID (Recommended)
    ),
    messaging.Message(
        notification=messaging.Notification('Price drop', '2% off all books'),
        token='YOUR_REGISTRATION_TOKEN', # Using token (Deprecated)
    ),
    messaging.Message(
        notification=messaging.Notification('Price drop', '10% off all shoes'),
        topic='readers-club',
    ),
]

response = messaging.send_each(messages)
# See the BatchResponse reference documentation
# for the contents of response.
print('{0} messages were sent successfully'.format(response.success_count))

使用註冊權杖 (已淘汰)：

# Create a list containing up to 500 messages.
messages = [
    messaging.Message(
        notification=messaging.Notification('Price drop', '5% off all electronics'),
        token=registration_token,
    ),
    # ...
    messaging.Message(
        notification=messaging.Notification('Price drop', '2% off all books'),
        topic='readers-club',
    ),
]

response = messaging.send_each(messages)
# See the BatchResponse reference documentation
# for the contents of response.
print(f'{response.success_count} messages were sent successfully')

Go

使用混合目標 (建議做法)：

// Create a list containing up to 500 messages.
messages := []*messaging.Message{
    {
        Notification: &messaging.Notification{
            Title: "Price drop",
            Body:  "5% off all electronics",
        },
        Fid: "YOUR_REGISTERED_FID", // Using FID (Recommended)
    },
    {
        Notification: &messaging.Notification{
            Title: "Price drop",
            Body:  "2% off all books",
        },
        Token: "YOUR_REGISTRATION_TOKEN", // Using token (Deprecated)
    },
    {
        Notification: &messaging.Notification{
            Title: "Price drop",
            Body:  "10% off all shoes",
        },
        Topic: "readers-club",
    },
}

br, err := client.SendEach(ctx, messages)
if err != nil {
    log.Fatalln(err)
}
// See the BatchResponse reference documentation
// for the contents of response.
fmt.Printf("%d messages were sent successfully\n", br.SuccessCount)

使用註冊權杖 (已淘汰)：

// Create a list containing up to 500 messages.
messages := []*messaging.Message{
	{
		Notification: &messaging.Notification{
			Title: "Price drop",
			Body:  "5% off all electronics",
		},
		Token: registrationToken,
	},
	{
		Notification: &messaging.Notification{
			Title: "Price drop",
			Body:  "2% off all books",
		},
		Topic: "readers-club",
	},
}

br, err := client.SendEach(context.Background(), messages)
if err != nil {
	log.Fatalln(err)
}

// See the BatchResponse reference documentation
// for the contents of response.
fmt.Printf("%d messages were sent successfully\n", br.SuccessCount)

C#

使用混合目標 (建議做法)：

// Create a list containing up to 500 messages.
var messages = new List<Message>()
{
    new Message()
    {
        Notification = new Notification()
        {
            Title = "Price drop",
            Body = "5% off all electronics",
        },
        Fid = "YOUR_REGISTERED_FID", // Using FID (Recommended)
    },
    new Message()
    {
        Notification = new Notification()
        {
            Title = "Price drop",
            Body = "2% off all books",
        },
        Token = "YOUR_REGISTRATION_TOKEN", // Using token (Deprecated)
    },
    new Message()
    {
        Notification = new Notification()
        {
            Title = "Price drop",
            Body = "10% off all shoes",
        },
        Topic = "readers-club",
    },
};

var response = await FirebaseMessaging.DefaultInstance.SendEachAsync(messages);
// See the BatchResponse reference documentation
// for the contents of response.
Console.WriteLine($"{response.SuccessCount} messages were sent successfully");

使用註冊權杖 (已淘汰)：

            // Create a list containing up to 500 messages.
            var messages = new List<Message>()
            {
                new Message()
                {
                    Notification = new Notification()
                    {
                        Title = "Price drop",
                        Body = "5% off all electronics",
                    },
#pragma warning disable CS0618
                    Token = registrationToken,
#pragma warning restore CS0618
                },
                new Message()
                {
                    Notification = new Notification()
                    {
                        Title = "Price drop",
                        Body = "2% off all books",
                    },
                    Topic = "readers-club",
                },
            };

            var response = await FirebaseMessaging.DefaultInstance.SendEachAsync(messages);
            // See the BatchResponse reference documentation
            // for the contents of response.
            Console.WriteLine($"{response.SuccessCount} messages were sent successfully");