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 會負責處理路由,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。
關於主題,請注意以下幾點:
- 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。
- 如果您需要向每位使用者的多個裝置傳送訊息,請考慮針對這些用途使用 裝置群組訊息傳送。
- 主題訊息支援每個主題的無限訂閱項目。不過,FCM 會在下列領域實施限制:
- 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。如果您在短時間內傳送太多訂閱要求,FCM 伺服器會傳回
429 RESOURCE_EXHAUSTED
(「配額超出」) 回應。以指數輪詢方式重試。
讓用戶端應用程式訂閱主題
您可以將註冊權杖清單傳遞至 Firebase Admin SDK 訂閱方法,讓對應裝置訂閱主題:
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()
方法會產生物件,其中包含 FCM 的回應。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。
如果發生錯誤 (驗證失敗、權杖或主題無效等),這些方法會導致錯誤。如需錯誤代碼的完整清單 (包括說明和解決步驟),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。如何在用戶端上處理訊息,取決於網頁的前景/背景狀態,以及本節所述的其他因素。
訊息的行為會因網頁處於前景 (有焦點)、背景、隱藏在其他分頁後方或完全關閉而有所不同。無論如何,網頁都必須處理 onMessage
回呼,但在背景情況下,您可能還需要處理 onBackgroundMessage
或設定顯示通知,讓使用者將您的網路應用程式帶到前景。
應用程式狀態 | 通知 | 資料 | 兩者並用 |
---|---|---|---|
前景 | onMessage |
onMessage |
onMessage |
背景 (Service Worker) | onBackgroundMessage (自動顯示通知) |
onBackgroundMessage |
onBackgroundMessage (自動顯示通知) |
在前景處理網頁應用程式訊息
如要接收 onMessage
事件,應用程式必須在 firebase-messaging-sw.js
中定義 Firebase 訊息服務 worker。或者,您也可以透過 getToken(): Promise<string>
,將現有的服務工作者提供給 SDK。
Web
import { initializeApp } from "firebase/app"; import { getMessaging } from "firebase/messaging/sw"; // Initialize the Firebase app in the service worker by passing in // your app's Firebase config object. // https://firebase.google.com/docs/web/setup#config-object const firebaseApp = initializeApp({ apiKey: 'api-key', authDomain: 'project-id.firebaseapp.com', databaseURL: 'https://project-id.firebaseio.com', projectId: 'project-id', storageBucket: 'project-id.appspot.com', messagingSenderId: 'sender-id', appId: 'app-id', measurementId: 'G-measurement-id', }); // Retrieve an instance of Firebase Messaging so that it can handle background // messages. const messaging = getMessaging(firebaseApp);
Web
// Give the service worker access to Firebase Messaging. // Note that you can only use Firebase Messaging here. Other Firebase libraries // are not available in the service worker. // Replace 10.13.2 with latest version of the Firebase JS SDK. importScripts('https://www.gstatic.com/firebasejs/10.13.2/firebase-app-compat.js'); importScripts('https://www.gstatic.com/firebasejs/10.13.2/firebase-messaging-compat.js'); // Initialize the Firebase app in the service worker by passing in // your app's Firebase config object. // https://firebase.google.com/docs/web/setup#config-object firebase.initializeApp({ apiKey: 'api-key', authDomain: 'project-id.firebaseapp.com', databaseURL: 'https://project-id.firebaseio.com', projectId: 'project-id', storageBucket: 'project-id.appspot.com', messagingSenderId: 'sender-id', appId: 'app-id', measurementId: 'G-measurement-id', }); // Retrieve an instance of Firebase Messaging so that it can handle background // messages. const messaging = firebase.messaging();
當應用程式處於前景 (使用者目前正在查看網頁) 時,您可以直接在網頁中接收資料和通知酬載。
Web
// Handle incoming messages. Called when: // - a message is received while the app has focus // - the user clicks on an app notification created by a service worker // `messaging.onBackgroundMessage` handler. import { getMessaging, onMessage } from "firebase/messaging"; const messaging = getMessaging(); onMessage(messaging, (payload) => { console.log('Message received. ', payload); // ... });
Web
// Handle incoming messages. Called when: // - a message is received while the app has focus // - the user clicks on an app notification created by a service worker // `messaging.onBackgroundMessage` handler. messaging.onMessage((payload) => { console.log('Message received. ', payload); // ... });
在網頁應用程式於背景執行時處理訊息
應用程式在背景執行時收到的所有訊息,都會觸發瀏覽器顯示通知。您可以透過應用程式伺服器的傳送要求,或在用戶端使用服務工作者邏輯,指定此通知的選項,例如標題或點擊動作。
在傳送要求中設定通知選項
針對從應用程式伺服器傳送的通知訊息,FCM JavaScript API 支援 fcm_options.link
鍵。通常會設為網站應用程式中的頁面:
https://fcm.googleapis.com//v1/projects/<YOUR-PROJECT-ID>/messages:send
Content-Type: application/json
Authorization: bearer <YOUR-ACCESS-TOKEN>
{
"message": {
"topic": "matchday",
"notification": {
"title": "Background Message Title",
"body": "Background message body"
},
"webpush": {
"fcm_options": {
"link": "https://dummypage.com"
}
}
}
}
如果連結值指向瀏覽器分頁中已開啟的網頁,點選通知即可將該分頁移至前景。如果網頁尚未開啟,點選通知後會在新分頁中開啟該網頁。
由於資料訊息不支援 fcm_options.link
,建議您在所有資料訊息中加入通知酬載。或者,您也可以使用服務工作者處理通知。
如要瞭解通知和資料訊息的差異,請參閱「訊息類型」。
在服務工作者中設定通知選項
針對資料訊息,您可以在服務工作者中設定通知選項。首先,請在服務工作站中初始化應用程式:
Web
import { initializeApp } from "firebase/app"; import { getMessaging } from "firebase/messaging/sw"; // Initialize the Firebase app in the service worker by passing in // your app's Firebase config object. // https://firebase.google.com/docs/web/setup#config-object const firebaseApp = initializeApp({ apiKey: 'api-key', authDomain: 'project-id.firebaseapp.com', databaseURL: 'https://project-id.firebaseio.com', projectId: 'project-id', storageBucket: 'project-id.appspot.com', messagingSenderId: 'sender-id', appId: 'app-id', measurementId: 'G-measurement-id', }); // Retrieve an instance of Firebase Messaging so that it can handle background // messages. const messaging = getMessaging(firebaseApp);
Web
// Give the service worker access to Firebase Messaging. // Note that you can only use Firebase Messaging here. Other Firebase libraries // are not available in the service worker. // Replace 10.13.2 with latest version of the Firebase JS SDK. importScripts('https://www.gstatic.com/firebasejs/10.13.2/firebase-app-compat.js'); importScripts('https://www.gstatic.com/firebasejs/10.13.2/firebase-messaging-compat.js'); // Initialize the Firebase app in the service worker by passing in // your app's Firebase config object. // https://firebase.google.com/docs/web/setup#config-object firebase.initializeApp({ apiKey: 'api-key', authDomain: 'project-id.firebaseapp.com', databaseURL: 'https://project-id.firebaseio.com', projectId: 'project-id', storageBucket: 'project-id.appspot.com', messagingSenderId: 'sender-id', appId: 'app-id', measurementId: 'G-measurement-id', }); // Retrieve an instance of Firebase Messaging so that it can handle background // messages. const messaging = firebase.messaging();
如要設定選項,請在 firebase-messaging-sw.js
中呼叫 onBackgroundMessage
。在本範例中,我們會建立包含標題、內文和圖示欄位的通知。
Web
import { getMessaging } from "firebase/messaging/sw"; import { onBackgroundMessage } from "firebase/messaging/sw"; const messaging = getMessaging(); onBackgroundMessage(messaging, (payload) => { console.log('[firebase-messaging-sw.js] Received background message ', payload); // Customize notification here const notificationTitle = 'Background Message Title'; const notificationOptions = { body: 'Background Message body.', icon: '/firebase-logo.png' }; self.registration.showNotification(notificationTitle, notificationOptions); });
Web
messaging.onBackgroundMessage((payload) => { console.log( '[firebase-messaging-sw.js] Received background message ', payload ); // Customize notification here const notificationTitle = 'Background Message Title'; const notificationOptions = { body: 'Background Message body.', icon: '/firebase-logo.png' }; self.registration.showNotification(notificationTitle, notificationOptions); });
建立傳送要求
建立主題後,您可以透過訂閱用戶端應用程式執行個體,或透過伺服器 API,將訊息傳送至主題。如果這是您首次為 FCM 建立傳送要求,請參閱伺服器環境和 FCM 指南,瞭解重要背景資訊和設定資訊。
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,下列條件會將訊息傳送至已訂閱 TopicA
和 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,未訂閱 TopicA
的使用者也不會收到訊息。以下組合會收到這項通知:
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
- 進一步瞭解傳送至多部裝置的其他方式:裝置群組訊息