我想知道是否可以在 Firebase 在特定实体上添加新子项时向 Android 移动设备发送推送通知。 例如，假设 Firebase 上有一个名为 Tasks 的实体。每当向该 firebase 集合添加新任务时，都会触发“child_added”事件，然后以某种方式向移动客户端发送推送通知。 触发器是 child_added 事件。但是，我不确定直接从 Firebase 事件发送推送通知是否可行。
【问题讨论】：
标签： android firebase push-notification
编辑：您应该看看Firebase Cloud Functions，它让您无需创建 Node.js 服务器即可完成此操作
【讨论】：
您可以制作一个非常简单的 node.js 服务器或 java servlet（根据您的语言偏好），然后使用 firebase server sdk 添加 childEventListener。当值更改时，您可以使用 FCM 使用 http 协议发送推送通知。我在我的应用程序中使用它，它非常可行和可靠。
注意：如果您将此流程用于 android 应用程序，那么使用 java server sdk 将是有益的，因为它与您在 android 上的几乎相似。
编辑：在得到一些关于这个答案的关注之后，我想分享一些关于相同的更多信息。
//this official firebase blog 上看到的示例 node.js 服务器
var firebase = require('firebase');
var request = require('request');
var API_KEY = "..."; // Your Firebase Cloud Server API key
firebase.initializeApp({
serviceAccount: ".json",
databaseURL: "https://.firebaseio.com/"
});
ref = firebase.database().ref();
function listenForNotificationRequests() {
var requests = ref.child('notificationRequests');
ref.on('child_added', function(requestSnapshot) {
var request = requestSnapshot.val();
sendNotificationToUser(
request.username,
request.message,
function() {
request.ref().remove();
}
);
}, function(error) {
console.error(error);
});
};
function sendNotificationToUser(username, message, onSuccess) {
request({
url: 'https://fcm.googleapis.com/fcm/send',
method: 'POST',
headers: {
'Content-Type' :' application/json',
'Authorization': 'key='+API_KEY
},
body: JSON.stringify({
notification: {
title: message
},
to : '/topics/user_'+username
})
}, function(error, response, body) {
if (error) { console.error(error); }
else if (response.statusCode >= 400) {
console.error('HTTP Error: '+response.statusCode+' - '+response.statusMessage);
}
else {
onSuccess();
}
});
}
// start listening
listenForNotificationRequests();
//示例测试 java servlet 我只是为了演示这个用例
@WebServlet("/TestServlet")
public class MainServlet extends HttpServlet {
* @see HttpServlet#HttpServlet()
*/
public MainServlet() {
super();
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// Get context and then relative path to saved json config file from
// firebase
ServletContext context = getServletContext();
String fullPath = context.getRealPath(FILE_PATH_FOR_JSON_SERVER_AUTH);
// Check if we actually got a file from above path
if (fullPath != null) {
} else {
}
// Setup connection to firebase database here
FirebaseOptions options = new FirebaseOptions.Builder().setServiceAccount(new FileInputStream(fullPath))
.setDatabaseUrl(FIREBASE_DATABSE_URL).build();
// Check to make sure we don't initialize firebase app each time webpage
// is refreshed
if (!exists) {
// If firebase app doesn't exist then initialize it here and set
// exists to true
FirebaseApp.initializeApp(options);
exists = true;
}
// Call this to begin listening *notify* node in firebase database for notifications
addNotificationListener(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// Build apache httpclient POST request
HttpClient client = HttpClientBuilder.create().build();
HttpPost post = new HttpPost(ENDPOINT_URL);
//Get the required id stored in lastMsgId tree map here
if (!(chatLogs.getLastMsgIdTreeMap().isEmpty())) {
sendToID = chatLogs.getLastMsgIdTreeMap().firstKey();
lstmsg = chatLogs.getLastMsgIdTreeMap().get(sendToID);
}
//Set up a unique id with concatenating sendToID and lstmsg
uniqueID = sendToID + lstmsg;
//Set up a previous id to check with unique id. To avoid instant duplicate notifications
previousID = fcmHelper.getPreviousid();
// Check uniqueId and PreviousID beforeSending
if (!(uniqueID.equals(previousID))) {
fcmHelper.setPreviousid(uniqueID);
//Check if device token and user Id hashmap is not null
if (!(userLogs.getUserIdAndFcmTokenHashMap().isEmpty())) {
//Get the device token of sendTo Id here
deviceToken = userLogs.getUserIdAndFcmTokenHashMap().get(sendToID);
// Create JSON object for downstream data/notification
JSONObject mainNotificationJsonObj = new JSONObject();
JSONObject outerBaseJsonObj = new JSONObject();
try {
// Notification payload has 'title' and 'body' key
mainNotificationJsonObj.put(TITLE, NEW_MESSAGE_RECEIVED);
mainNotificationJsonObj.put(BODY, lstmsg);
mainNotificationJsonObj.put(NOTIFICATION_SOUND, NOTIFICATION_SOUND_TYPE_DEFAULT);
//mainNotificationJsonObj.put(TAG, fcmHelper.getFcmTagId());
System.out.println("This is sentBy id =" + fcmHelper.getFcmTagId());
// This will be used in case of both 'notification' or 'data' payload
outerBaseJsonObj.put(TO, deviceToken);
// Set priority of notification. For instant chat setting
// high will
// wake device from idle state - HIGH BATTERY DRAIN
outerBaseJsonObj.put(PRIORITY_KEY, PRIORITY_HIGH);
// Specify required payload key here either 'data' or
// 'notification'. We can even use both payloads in single
// message
outerBaseJsonObj.put(NOTIFICATION, mainNotificationJsonObj);
} catch (JSONException e) {
e.printStackTrace();
}
// Setup http entity with json data and 'Content-Type' header
StringEntity requestEntity = new StringEntity(outerBaseJsonObj.toString(),
ContentType.APPLICATION_JSON);
// Setup required Authorization header
post.setHeader(AUTHORIZATION, FIREBASE_SERVER_KEY);
// Pass setup entity to post request here
post.setEntity(requestEntity);
// Execute apache http client post response
HttpResponse fcmResponse = client.execute(post);
// Get status code from FCM server to debug error and success
System.out.println(RESPONSE_CODE + fcmResponse.getStatusLine().getStatusCode());
// Get response entity from FCM server and read throw lines
BufferedReader rd = new BufferedReader(new InputStreamReader(fcmResponse.getEntity().getContent()));
StringBuffer result = new StringBuffer();
String line = "";
while ((line = rd.readLine()) != null) {
result.append(line);
}
if (response != null) {
// Print out the response to webpage
PrintWriter out;
out = response.getWriter();
out.println(result);
System.out.println("This is Result - " + result);
}
} else {
//Abort this process if conditions not met
post.abort();
System.out.println(THIS_MSG_ALREADY_SENT);
}
}
}
/*
* This is the main method to be called to setup notifications listener on server startup
*/
private void addNotificationListener(HttpServletRequest request, HttpServletResponse response) {
//Initialize Value event listener
lastMsgListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot arg0) {
// Clear idLastMessagerecivedhash map if not null
if (lastMsgIdTreeMap != null) {
lastMsgIdTreeMap.clear();
}
//Get lastmsg to be sent as notification here
lstmsg = (String) arg0.child(LAST_MESSAGE).getValue();
//Get sendToID here
String sendToID = (String) arg0.child(SEND_TO).getValue();
//Get Sent by ID here
sentBy = (String) arg0.child(SENT_BY).getValue();
//Set fcmTag ID here
fcmHelper.setFcmTagId(sentBy);
//Check if lstmsg is not null
if (lstmsg != null) {
// Create lastmsgTimestampHashMap here
lastMsgIdTreeMap.put(sendToID, lstmsg);
}
//Check for null again
if (lastMsgIdTreeMap != null) {
chatLogs.setLastMsgIdTreeMap(lastMsgIdTreeMap);
}
try {
doPost(request, response);
} catch (ServletException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onCancelled(DatabaseError arg0) {
}
};
//Set up database reference to notify node here
messageRef = FirebaseDatabase.getInstance().getReference().child(NOTIFY);
//Add value listener to database reference here
messageRef.addValueEventListener(lastMsgListener);
}
“Java servlet 只是一个个人测试。某些部分已被编辑或删除，只是为了说明它的设置这绝不是生产就绪的 servlet，请不要只是复制粘贴。我鼓励你去理解和建立你自己的。”
【讨论】：