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向 Apple 平台上的主題發送消息

透過集合功能整理內容 你可以依據偏好儲存及分類內容。

基於發布/訂閱模型,FCM 主題消息傳遞允許您向已選擇加入特定主題的多個設備發送消息。您可以根據需要撰寫主題消息,FCM 負責處理路由並將消息可靠地傳遞到正確的設備。

例如,本地潮汐預報應用程序的用戶可以選擇“潮汐流警報”主題並接收指定區域最佳鹹水捕魚條件的通知。體育應用程序的用戶可以訂閱他們最喜歡的球隊實時比賽比分的自動更新。

有關主題的一些注意事項:

  • 主題消息最適合天氣或其他公開信息等內容。
  • 主題消息針對吞吐量而不是延遲進行了優化。為了快速、安全地傳送到單個設備或一小組設備,將消息定位到註冊令牌,而不是主題。
  • 如果您需要向每個用戶的多個設備發送消息,請考慮針對這些用例的設備組消息傳遞
  • 主題消息支持對每個主題的無限訂閱。但是,FCM 在這些方面實施了限制:
    • 一個應用實例可以訂閱不超過 2000 個主題。
    • 如果您使用批量導入訂閱應用實例,則每個請求限制為 1000 個應用實例。
    • 新訂閱的頻率受每個項目的速率限制。如果您在短時間內發送過多的訂閱請求,FCM 服務器將響應429 RESOURCE_EXHAUSTED (“超出配額”)響應。使用指數退避重試。

為客戶端應用程序訂閱主題

客戶端應用程序可以訂閱任何現有主題,也可以創建新主題。當客戶端應用程序訂閱一個新主題名稱(您的 Firebase 項目尚不存在的主題名稱)時,將在 FCM 中創建一個具有該名稱的新主題,隨後任何客戶端都可以訂閱它。

要訂閱主題,請從應用程序的主線程調用訂閱方法(FCM 不是線程安全的)。如果訂閱請求最初失敗,FCM 會自動重試。對於無法完成訂閱的情況,訂閱會拋出一個錯誤,您可以在完成處理程序中捕獲該錯誤,如下所示:

迅速

Messaging.messaging().subscribe(toTopic: "weather") { error in
  print("Subscribed to weather topic")
}

目標-C

[[FIRMessaging messaging] subscribeToTopic:@"weather"
                                completion:^(NSError * _Nullable error) {
  NSLog(@"Subscribed to weather topic");
}];

此調用向 FCM 後端發出異步請求,並為客戶端訂閱給定主題。在調用subscribeToTopic:topic之前,確保客戶端應用程序實例已經通過回調didReceiveRegistrationToken接收到註冊令牌。

每次應用程序啟動時,FCM 都會確保所有請求的主題都已訂閱。要取消訂閱,請調用unsubscribeFromTopic:topic ,FCM 會在後台取消訂閱該主題。

在服務器上管理主題訂閱

Firebase Admin SDK允許您從服務器端執行基本的主題管理任務。鑑於他們的註冊令牌,您可以使用服務器邏輯批量訂閱和取消訂閱客戶端應用程序實例。

您可以將客戶端應用程序實例訂閱到任何現有主題,也可以創建新主題。當您使用 API 為客戶端應用程序訂閱一個新主題(您的 Firebase 項目尚不存在的主題)時,將在 FCM 中創建一個同名的新主題,隨後任何客戶端都可以訂閱它。

您可以將註冊令牌列表傳遞給 Firebase Admin SDK 訂閱方法,以便為相應的設備訂閱主題:

節點.js

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

// Subscribe the devices corresponding to the registration tokens to the
// topic.
getMessaging().subscribeToTopic(registrationTokens, topic)
  .then((response) => {
    // See the MessagingTopicManagementResponse reference documentation
    // for the contents of response.
    console.log('Successfully subscribed to topic:', response);
  })
  .catch((error) => {
    console.log('Error subscribing to topic:', error);
  });

爪哇

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

// Subscribe the devices corresponding to the registration tokens to the
// topic.
TopicManagementResponse response = FirebaseMessaging.getInstance().subscribeToTopic(
    registrationTokens, topic);
// See the TopicManagementResponse reference documentation
// for the contents of response.
System.out.println(response.getSuccessCount() + " tokens were subscribed successfully");

Python

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

# Subscribe the devices corresponding to the registration tokens to the
# topic.
response = messaging.subscribe_to_topic(registration_tokens, topic)
# See the TopicManagementResponse reference documentation
# for the contents of response.
print(response.success_count, 'tokens were subscribed successfully')

// These registration tokens come from the client FCM SDKs.
registrationTokens := []string{
	"YOUR_REGISTRATION_TOKEN_1",
	// ...
	"YOUR_REGISTRATION_TOKEN_n",
}

// Subscribe the devices corresponding to the registration tokens to the
// topic.
response, err := client.SubscribeToTopic(ctx, registrationTokens, topic)
if err != nil {
	log.Fatalln(err)
}
// See the TopicManagementResponse reference documentation
// for the contents of response.
fmt.Println(response.SuccessCount, "tokens were subscribed successfully")

C#

// These registration tokens come from the client FCM SDKs.
var registrationTokens = new List<string>()
{
    "YOUR_REGISTRATION_TOKEN_1",
    // ...
    "YOUR_REGISTRATION_TOKEN_n",
};

// Subscribe the devices corresponding to the registration tokens to the
// topic
var response = await FirebaseMessaging.DefaultInstance.SubscribeToTopicAsync(
    registrationTokens, topic);
// See the TopicManagementResponse reference documentation
// for the contents of response.
Console.WriteLine($"{response.SuccessCount} tokens were subscribed successfully");

Admin FCM API 還允許您通過將註冊令牌傳遞給適當的方法來取消訂閱設備的主題:

節點.js

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

// Unsubscribe the devices corresponding to the registration tokens from
// the topic.
getMessaging().unsubscribeFromTopic(registrationTokens, topic)
  .then((response) => {
    // See the MessagingTopicManagementResponse reference documentation
    // for the contents of response.
    console.log('Successfully unsubscribed from topic:', response);
  })
  .catch((error) => {
    console.log('Error unsubscribing from topic:', error);
  });

爪哇

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

// Unsubscribe the devices corresponding to the registration tokens from
// the topic.
TopicManagementResponse response = FirebaseMessaging.getInstance().unsubscribeFromTopic(
    registrationTokens, topic);
// See the TopicManagementResponse reference documentation
// for the contents of response.
System.out.println(response.getSuccessCount() + " tokens were unsubscribed successfully");

Python

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

# Unubscribe the devices corresponding to the registration tokens from the
# topic.
response = messaging.unsubscribe_from_topic(registration_tokens, topic)
# See the TopicManagementResponse reference documentation
# for the contents of response.
print(response.success_count, 'tokens were unsubscribed successfully')

// These registration tokens come from the client FCM SDKs.
registrationTokens := []string{
	"YOUR_REGISTRATION_TOKEN_1",
	// ...
	"YOUR_REGISTRATION_TOKEN_n",
}

// Unsubscribe the devices corresponding to the registration tokens from
// the topic.
response, err := client.UnsubscribeFromTopic(ctx, registrationTokens, topic)
if err != nil {
	log.Fatalln(err)
}
// See the TopicManagementResponse reference documentation
// for the contents of response.
fmt.Println(response.SuccessCount, "tokens were unsubscribed successfully")

C#

// These registration tokens come from the client FCM SDKs.
var registrationTokens = new List<string>()
{
    "YOUR_REGISTRATION_TOKEN_1",
    // ...
    "YOUR_REGISTRATION_TOKEN_n",
};

// Unsubscribe the devices corresponding to the registration tokens from the
// topic
var response = await FirebaseMessaging.DefaultInstance.UnsubscribeFromTopicAsync(
    registrationTokens, topic);
// See the TopicManagementResponse reference documentation
// for the contents of response.
Console.WriteLine($"{response.SuccessCount} tokens were unsubscribed successfully");

subscribeToTopic()unsubscribeFromTopic()方法生成一個包含來自 FCM 的響應的對象。無論請求中指定的註冊令牌數量如何,返回類型都具有相同的格式。

如果出現錯誤(身份驗證失敗、無效令牌或主題等),這些方法會導致錯誤。有關錯誤代碼的完整列表,包括描述和解決步驟,請參閱管理 FCM API 錯誤

接收和處理主題消息

FCM 以與其他下游消息相同的方式傳遞主題消息。

實現application(_:didReceiveRemoteNotification:fetchCompletionHandler:)如下所示:

迅速

func application(_ application: UIApplication,
                 didReceiveRemoteNotification userInfo: [AnyHashable: Any]) async
  -> UIBackgroundFetchResult {
  // If you are receiving a notification message while your app is in the background,
  // this callback will not be fired till the user taps on the notification launching the application.
  // TODO: Handle data of notification

  // With swizzling disabled you must let Messaging know about the message, for Analytics
  // Messaging.messaging().appDidReceiveMessage(userInfo)

  // Print message ID.
  if let messageID = userInfo[gcmMessageIDKey] {
    print("Message ID: \(messageID)")
  }

  // Print full message.
  print(userInfo)

  return UIBackgroundFetchResult.newData
}

目標-C

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
    fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
  // If you are receiving a notification message while your app is in the background,
  // this callback will not be fired till the user taps on the notification launching the application.
  // TODO: Handle data of notification

  // With swizzling disabled you must let Messaging know about the message, for Analytics
  // [[FIRMessaging messaging] appDidReceiveMessage:userInfo];

  // ...

  // Print full message.
  NSLog(@"%@", userInfo);

  completionHandler(UIBackgroundFetchResultNewData);
}

構建發送請求

創建主題後,通過在客戶端訂閱客戶端應用程序實例或通過服務器 API訂閱主題,您可以向主題發送消息。如果這是您第一次為 FCM 構建發送請求,請參閱您的服務器環境和 FCM指南,了解重要的背景和設置信息。

在後端的發送邏輯中,指定所需的主題名稱,如下所示:

節點.js

// The topic name can be optionally prefixed with "/topics/".
const topic = 'highScores';

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

// Send a message to devices subscribed to the provided topic.
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);
  });

爪哇

// The topic name can be optionally prefixed with "/topics/".
String topic = "highScores";

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

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

Python

# The topic name can be optionally prefixed with "/topics/".
topic = 'highScores'

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

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

// The topic name can be optionally prefixed with "/topics/".
topic := "highScores"

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

// Send a message to the devices subscribed to the provided topic.
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#

// The topic name can be optionally prefixed with "/topics/".
var topic = "highScores";

// See documentation on defining a message payload.
var message = new Message()
{
    Data = new Dictionary<string, string>()
    {
        { "score", "850" },
        { "time", "2:45" },
    },
    Topic = topic,
};

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

休息

POST https://fcm.googleapis.com/v1/projects/myproject-b5ae1/messages:send HTTP/1.1

Content-Type: application/json
Authorization: Bearer ya29.ElqKBGN2Ri_Uz...HnS_uNreA
{
  "message":{
    "topic" : "foo-bar",
    "notification" : {
      "body" : "This is a Firebase Cloud Messaging Topic Message!",
      "title" : "FCM Message"
      }
   }
}

捲曲命令:

curl -X POST -H "Authorization: Bearer ya29.ElqKBGN2Ri_Uz...HnS_uNreA" -H "Content-Type: application/json" -d '{
  "message": {
    "topic" : "foo-bar",
    "notification": {
      "body": "This is a Firebase Cloud Messaging Topic Message!",
      "title": "FCM Message"
    }
  }
}' https://fcm.googleapis.com/v1/projects/myproject-b5ae1/messages:send HTTP/1.1

要向主題組合發送消息,請指定condition ,它是指定目標主題的布爾表達式。例如,以下條件會將消息發送到訂閱了TopicATopicBTopicC的設備:

"'TopicA' in topics && ('TopicB' in topics || 'TopicC' in topics)"

FCM 首先計算括號中的任何條件,然後從左到右計算表達式。在上面的表達式中,訂閱任何單個主題的用戶不會收到消息。同樣,未訂閱TopicA的用戶也不會收到消息。這些組合確實收到了它:

  • TopicATopicB
  • TopicATopicC

您最多可以在條件表達式中包含五個主題。

發送到一個條件:

節點.js

// Define a condition which will send to devices which are subscribed
// to either the Google stock or the tech industry topics.
const condition = '\'stock-GOOG\' in topics || \'industry-tech\' in topics';

// See documentation on defining a message payload.
const message = {
  notification: {
    title: '$FooCorp up 1.43% on the day',
    body: '$FooCorp gained 11.80 points to close at 835.67, up 1.43% on the day.'
  },
  condition: condition
};

// Send a message to devices subscribed to the combination of topics
// specified by the provided condition.
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);
  });

爪哇

// Define a condition which will send to devices which are subscribed
// to either the Google stock or the tech industry topics.
String condition = "'stock-GOOG' in topics || 'industry-tech' in topics";

// See documentation on defining a message payload.
Message message = Message.builder()
    .setNotification(Notification.builder()
        .setTitle("$GOOG up 1.43% on the day")
        .setBody("$GOOG gained 11.80 points to close at 835.67, up 1.43% on the day.")
        .build())
    .setCondition(condition)
    .build();

// Send a message to devices subscribed to the combination of topics
// specified by the provided condition.
String response = FirebaseMessaging.getInstance().send(message);
// Response is a message ID string.
System.out.println("Successfully sent message: " + response);

Python

# Define a condition which will send to devices which are subscribed
# to either the Google stock or the tech industry topics.
condition = "'stock-GOOG' in topics || 'industry-tech' in topics"

# See documentation on defining a message payload.
message = messaging.Message(
    notification=messaging.Notification(
        title='$GOOG up 1.43% on the day',
        body='$GOOG gained 11.80 points to close at 835.67, up 1.43% on the day.',
    ),
    condition=condition,
)

# Send a message to devices subscribed to the combination of topics
# specified by the provided condition.
response = messaging.send(message)
# Response is a message ID string.
print('Successfully sent message:', response)

// Define a condition which will send to devices which are subscribed
// to either the Google stock or the tech industry topics.
condition := "'stock-GOOG' in topics || 'industry-tech' in topics"

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

// Send a message to devices subscribed to the combination of topics
// specified by the provided condition.
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#

// Define a condition which will send to devices which are subscribed
// to either the Google stock or the tech industry topics.
var condition = "'stock-GOOG' in topics || 'industry-tech' in topics";

// See documentation on defining a message payload.
var message = new Message()
{
    Notification = new Notification()
    {
        Title = "$GOOG up 1.43% on the day",
        Body = "$GOOG gained 11.80 points to close at 835.67, up 1.43% on the day.",
    },
    Condition = condition,
};

// Send a message to devices subscribed to the combination of topics
// specified by the provided condition.
string response = await FirebaseMessaging.DefaultInstance.SendAsync(message);
// Response is a message ID string.
Console.WriteLine("Successfully sent message: " + response);

休息

POST https://fcm.googleapis.com/v1/projects/myproject-b5ae1/messages:send HTTP/1.1

Content-Type: application/json
Authorization: Bearer ya29.ElqKBGN2Ri_Uz...HnS_uNreA
{
   "message":{
    "condition": "'dogs' in topics || 'cats' in topics",
    "notification" : {
      "body" : "This is a Firebase Cloud Messaging Topic Message!",
      "title" : "FCM Message",
    }
  }
}

捲曲命令:

curl -X POST -H "Authorization: Bearer ya29.ElqKBGN2Ri_Uz...HnS_uNreA" -H "Content-Type: application/json" -d '{
  "notification": {
    "title": "FCM Message",
    "body": "This is a Firebase Cloud Messaging Topic Message!",
  },
  "condition": "'dogs' in topics || 'cats' in topics"
}' https://fcm.googleapis.com/v1/projects/myproject-b5ae1/messages:send HTTP/1.1

下一步

  • 了解更多關於發送到多個設備的另一種方式——設備組消息