FCM 主題訊息功能採用發布/訂閱模式,可讓您向已選擇加入特定主題的多部裝置傳送訊息。您可以視需要撰寫主題訊息,FCM 會處理路由,並將訊息可靠地傳送至正確的裝置。
舉例來說,當地潮汐預測應用程式的使用者可以選擇訂閱「潮流警報」主題,接收特定地區最佳鹽水釣魚條件的通知。運動應用程式的使用者可以訂閱喜愛球隊的即時比數自動更新功能。
使用主題時,請注意下列事項:
- 主題訊息最適合用於天氣或其他公開資訊等內容。
- 主題訊息是針對總處理量而非延遲進行最佳化。如要快速安全地傳送至單一裝置或小型裝置群組,請將訊息指定給註冊權杖,而非主題。
- 如需「依使用者」傳送訊息給多部裝置,建議您 裝置群組訊息 適合這些用途
- 每個主題的訊息功能支援無限次訂閱。不過,FCM
在這些方面施行限制:
- 一個應用程式執行個體最多只能訂閱 2,000 個主題。
- 如果您使用批次匯入功能來訂閱應用程式執行個體,每個要求最多只能包含 1,000 個應用程式執行個體。
- 每個專案的新訂閱頻率都有限制。如果傳送過多
在短時間內訂閱要求,FCM 的伺服器會回應
429 RESOURCE_EXHAUSTED
(「超過配額」) 回應。以指數輪詢方式重試。
為用戶端應用程式訂閱主題
用戶端應用程式可以訂閱任何現有主題,也可以建立新主題。用戶端應用程式訂閱新的主題名稱時 (具有 Firebase 專案尚不存在的新主題,但這個名稱的新主題會是 在 FCM 中建立,且任何用戶端皆可訂閱其後續服務。
如要訂閱主題,請從應用程式的主要執行緒呼叫訂閱方法 (FCM 不安全)。如果訂閱要求一開始失敗,FCM 會自動重試。 如果無法完成訂閱,訂閱項目會擲回錯誤,您可以在完成處理常式中擷取這類錯誤,如下所示:
Swift
Messaging.messaging().subscribe(toTopic: "weather") { error in print("Subscribed to weather topic") }
Objective-C
[[FIRMessaging messaging] subscribeToTopic:@"weather" completion:^(NSError * _Nullable error) { NSLog(@"Subscribed to weather topic"); }];
此呼叫會向 FCM 後端提出非同步要求,並讓用戶端訂閱指定主題。在呼叫 subscribeToTopic:topic
之前,請確認用戶端應用程式例項已透過回呼 didReceiveRegistrationToken
收到註冊權杖。
每次應用程式啟動時
「FCM」確認已訂閱所有要求的主題。目的地:
取消訂閱、撥打 unsubscribeFromTopic:topic
,
和 FCM 在背景取消訂閱主題。
管理伺服器上的主題訂閱
Firebase Admin SDK 可讓您執行基本的 從伺服器端執行主題管理工作有鑑於此 權杖化),您可以使用以下指令大量訂閱和取消訂閱用戶端應用程式執行個體 伺服器邏輯
您可以將用戶端應用程式執行個體訂閱到任何現有主題,或 可以建立新主題當您使用 API 將用戶端應用程式訂閱至新主題 (您的 Firebase 專案中不存在的) 時,系統會在 FCM 中建立同名的新主題,之後任何用戶端都可以訂閱該主題。
您可以將註冊權杖清單傳遞至 Firebase Admin SDK 訂閱對應方法,藉此訂閱特定主題:
Node.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);
});
Java
// 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')
Go
// 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");
管理員 FCM API 還可讓您將裝置從主題取消訂閱,方法是將註冊權杖傳遞至適當的方法:
Node.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);
});
Java
// 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')
Go
// 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()
和 unsubscribeFromTopic()
方法會使
包含 FCM 回應的物件。無論要求中指定的註冊符記號數量為何,傳回類型都會採用相同的格式。
發生錯誤 (驗證失敗、憑證無效或主題等) 會導致錯誤發生 完整的錯誤代碼清單 (包括說明) 和解決方法,請參閱 Admin FCM API 錯誤。
接收及處理主題訊息
FCM 會以與其他下游訊息相同的方式傳送主題訊息。
導入application(_:didReceiveRemoteNotification:fetchCompletionHandler:)
如下所示:
Swift
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 }
Objective-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); }
版本傳送要求
建立主題後,您可以透過訂閱用戶端應用程式執行個體 在用戶端或 server API 進行連線,您就能傳送訊息至 主題。如果這是您首次為 FCM 建立傳送要求,請參閱指南,瞭解伺服器環境和 FCM 的重要背景和設定資訊。
在後端的傳送邏輯中,指定所需的專案名稱,如下所示:
Node.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);
});
Java
// 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)
Go
// 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);
REST
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"
}
}
}
cURL 指令:
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
如要將訊息傳送至主題組合,請指定條件,這是指定目標主題的布林運算式。舉例來說,當郵件符合下列條件時,
訂閱 TopicA
且 TopicB
或 TopicC
的裝置:
"'TopicA' in topics && ('TopicB' in topics || 'TopicC' in topics)"
FCM 會先評估括號中的任何條件,然後從左到右評估運算式。在上述運算式中,訂閱任何單一主題的使用者都不會收到訊息。同樣地,如果使用者未
訂閱 TopicA
並未收到訊息。這些組合
收到:
TopicA
和TopicB
TopicA
和TopicC
您最多可以在條件式運算式中加入五個主題。
如要傳送至條件:
Node.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);
});
Java
// 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)
Go
// 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);
REST
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",
}
}
}
cURL 指令:
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
後續步驟
- 進一步瞭解傳送到多部裝置的其他方式。 裝置群組訊息