我在浏览器上时看不到 Firebase 通知
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【中文标题】我在浏览器上时看不到 Firebase 通知【英文标题】：Not able to see Firebase notifications when I am on browser 【发布时间】：2020-04-27 16:19:08 【问题描述】：我想将 Firebase 网络通知从 FCM 发送到 PWA 应用。当我在浏览器上时无法看到我的 Firebase 通知，但是当我离开浏览器（手机的主屏幕）时我可以看到通知。 我不明白这个问题。请帮助我。提前致谢。
我的 firebase-messaging-sw.js
// are not available in the service worker.
importScripts('https://www.gstatic.com/firebasejs/7.14.0/firebase-app.js');
importScripts('https://www.gstatic.com/firebasejs/7.14.0/firebase-messaging.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();
// [END initialize_firebase_in_sw]
**/
// If you would like to customize notifications that are received in the
// background (Web app is closed or not in browser focus) then you should
// implement this optional method.
// [START background_handler]
messaging.setBackgroundMessageHandler(function(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'
;
return self.registration.showNotification(notificationTitle,
notificationOptions);
);
这是我的 index.html
<!--
Copyright (c) 2016 Google Inc.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<html>
<head>
<meta charset=utf-8 />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Firebase Cloud Messaging Example</title>
<!-- Material Design Theming -->
<link rel="stylesheet" href="https://code.getmdl.io/1.1.3/material.orange-indigo.min.css">
<link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
<script defer src="https://code.getmdl.io/1.1.3/material.min.js"></script>
<link rel="stylesheet" href="main.css">
<link rel="manifest" href="/manifest.json">
</head>
<body>
<div class="demo-layout mdl-layout mdl-js-layout mdl-layout--fixed-header">
<!-- Header section containing title -->
<header class="mdl-layout__header mdl-color-text--white mdl-color--light-blue-700">
<div class="mdl-cell mdl-cell--12-col mdl-cell--12-col-tablet mdl-grid">
<div class="mdl-layout__header-row mdl-cell mdl-cell--12-col mdl-cell--12-col-tablet mdl-cell--8-col-desktop">
<h3>Firebase Cloud Messaging</h3>
</div>
</div>
</header>
<main class="mdl-layout__content mdl-color--grey-100">
<div class="mdl-cell mdl-cell--12-col mdl-cell--12-col-tablet mdl-grid">
<!-- Container for the Table of content -->
<div class="mdl-card mdl-shadow--2dp mdl-cell mdl-cell--12-col mdl-cell--12-col-tablet mdl-cell--12-col-desktop">
<div class="mdl-card__supporting-text mdl-color-text--grey-600">
<!-- div to display the generated Instance ID token -->
<div id="token_div" style="display: none;">
<h4>Instance ID Token</h4>
<p id="token" style="word-break: break-all;"></p>
<button class="mdl-button mdl-js-button mdl-button--raised mdl-button--colored"
onclick="deleteToken()">
Refresh Token
</button>
</div>
<!-- div to display the UI to allow the request for permission to
notify the user. This is shown if the app has not yet been
granted permission to notify. -->
<div id="permission_div" style="display: none;">
<h4>Needs Permission</h4>
<p id="token"></p>
<button class="mdl-button mdl-js-button mdl-button--raised mdl-button--colored"
onclick="requestPermission()">
Request Permission
</button>
</div>
<!-- div to display messages received by this app. -->
<div id="messages"></div>
</div>
</div>
</div>
</main>
</div>
<!-- Import and configure the Firebase SDK -->
<!-- These scripts are made available when the app is served or deployed on Firebase Hosting -->
<!-- If you do not serve/host your project using Firebase Hosting see https://firebase.google.com/docs/web/setup -->
<script src="/__/firebase/7.14.0/firebase-app.js"></script>
<script src="/__/firebase/7.14.0/firebase-messaging.js"></script>
<script src="/__/firebase/init.js"></script>
<script>
// [START get_messaging_object]
// Retrieve Firebase Messaging object.
const messaging = firebase.messaging();
// [END get_messaging_object]
// [START set_public_vapid_key]
// Add the public key generated from the console here.
messaging.usePublicVapidKey('BDTDxT_59kRHBjDTBwnDvFQcdy8Y8A8NvjFFzW2aMo27raPODdeX89pSBA6pxerBbmpBXaLxiadjiNHTDmComhs');
// [END set_public_vapid_key]
// IDs of divs that display Instance ID token UI or request permission UI.
const tokenDivId = 'token_div';
const permissionDivId = 'permission_div';
// [START refresh_token]
// Callback fired if Instance ID token is updated.
messaging.onTokenRefresh(() =>
messaging.getToken().then((refreshedToken) =>
console.log('Token refreshed.');
// Indicate that the new Instance ID token has not yet been sent to the
// app server.
setTokenSentToServer(false);
// Send Instance ID token to app server.
sendTokenToServer(refreshedToken);
// [START_EXCLUDE]
// Display new Instance ID token and clear UI of all previous messages.
resetUI();
// [END_EXCLUDE]
).catch((err) =>
console.log('Unable to retrieve refreshed token ', err);
showToken('Unable to retrieve refreshed token ', err);
);
);
// [END refresh_token]
// [START receive_message]
// 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.setBackgroundMessageHandler` handler.
messaging.onMessage((payload) =>
console.log('Message received. ', payload);
// [START_EXCLUDE]
// Update the UI to include the received message.
appendMessage(payload);
// [END_EXCLUDE]
);
// [END receive_message]
function resetUI()
clearMessages();
showToken('loading...');
// [START get_token]
// Get Instance ID token. Initially this makes a network call, once retrieved
// subsequent calls to getToken will return from cache.
messaging.getToken().then((currentToken) =>
if (currentToken)
sendTokenToServer(currentToken);
updateUIForPushEnabled(currentToken);
else
// Show permission request.
console.log('No Instance ID token available. Request permission to generate one.');
// Show permission UI.
updateUIForPushPermissionRequired();
setTokenSentToServer(false);
).catch((err) =>
console.log('An error occurred while retrieving token. ', err);
showToken('Error retrieving Instance ID token. ', err);
setTokenSentToServer(false);
);
// [END get_token]
function showToken(currentToken)
// Show token in console and UI.
const tokenElement = document.querySelector('#token');
tokenElement.textContent = currentToken;
// Send the Instance ID token your application server, so that it can:
// - send messages back to this app
// - subscribe/unsubscribe the token from topics
function sendTokenToServer(currentToken)
if (!isTokenSentToServer())
console.log('Sending token to server...' + currentToken);
// TODO(developer): Send the current token to your server.
setTokenSentToServer(true);
else
console.log('Token already sent to server so won\'t send it again ' +
'unless it changes');
function isTokenSentToServer()
return window.localStorage.getItem('sentToServer') === '1';
function setTokenSentToServer(sent)
window.localStorage.setItem('sentToServer', sent ? '1' : '0');
function showHideDiv(divId, show)
const div = document.querySelector('#' + divId);
if (show)
div.style = 'display: visible';
else
div.style = 'display: none';
function requestPermission()
console.log('Requesting permission...');
// [START request_permission]
Notification.requestPermission().then((permission) =>
if (permission === 'granted')
console.log('Notification permission granted.');
// TODO(developer): Retrieve an Instance ID token for use with FCM.
// [START_EXCLUDE]
// In many cases once an app has been granted notification permission,
// it should update its UI reflecting this.
resetUI();
// [END_EXCLUDE]
else
console.log('Unable to get permission to notify.');
);
// [END request_permission]
function deleteToken()
// Delete Instance ID token.
// [START delete_token]
messaging.getToken().then((currentToken) =>
messaging.deleteToken(currentToken).then(() =>
console.log('Token deleted.');
setTokenSentToServer(false);
// [START_EXCLUDE]
// Once token is deleted update UI.
resetUI();
// [END_EXCLUDE]
).catch((err) =>
console.log('Unable to delete token. ', err);
);
// [END delete_token]
).catch((err) =>
console.log('Error retrieving Instance ID token. ', err);
showToken('Error retrieving Instance ID token. ', err);
);
// Add a message to the messages element.
function appendMessage(payload)
const messagesElement = document.querySelector('#messages');
const dataHeaderELement = document.createElement('h5');
const dataElement = document.createElement('pre');
dataElement.style = 'overflow-x:hidden;';
dataHeaderELement.textContent = 'Received message:';
dataElement.textContent = JSON.stringify(payload, null, 2);
messagesElement.appendChild(dataHeaderELement);
messagesElement.appendChild(dataElement);
// Clear the messages element of all children.
function clearMessages()
const messagesElement = document.querySelector('#messages');
while (messagesElement.hasChildNodes())
messagesElement.removeChild(messagesElement.lastChild);
function updateUIForPushEnabled(currentToken)
showHideDiv(tokenDivId, true);
showHideDiv(permissionDivId, false);
showToken(currentToken);
function updateUIForPushPermissionRequired()
showHideDiv(tokenDivId, false);
showHideDiv(permissionDivId, true);
resetUI();
</script>
</body>
</html>
如果您需要更多信息，请告诉我。
【问题讨论】：
【参考方案1】：将此代码添加到您的 js 文件而不是 service-worker.js 文件中
当web应用在前台触发onMessage事件时
messaging.onMessage(function(payload)
const notificationTitle = payload.notification.title;
const notificationOptions =
body: payload.notification.body,
icon: payload.notification.icon,
;
// console.log(notificationTitle,notificationOptions)
if (!("Notification" in window))
console.log("This browser does not support system notifications.");
else if (Notification.permission === "granted")
// If it's okay let's create a notification
var notification = new Notification(notificationTitle,notificationOptions);
notification.onclick = function(event)
event.preventDefault();
window.open(payload.notification.click_action , '_blank');
notification.close();
);
【讨论】：
【参考方案2】：你还需要处理标签打开的情况
在你的 firebase-messaging-sw.js 中实现这个方法
// Handle incoming messages. Called when:
// - a message is received while the app has focus
messaging.onMessage((payload) =>
console.log('Message received. ', payload);
);
【讨论】：
感谢您的建议，但出现以下错误。 未捕获的 FirebaseError：消息：此方法在 Window 上下文中可用。 （消息/仅在窗口中可用）。我再次在脚本标记内的 html 页面中尝试了此方法，结果：未显示通知。 （如下所示`return self.registration.showNotification(notificationTitle, notificationOptions);)` 如果这对您不起作用，可以尝试在 firebase-messaging-sw.js 中列出简单的推送事件，这在选项卡打开时适用于两种情况或关闭 -self.addEventListener("push", payload => console.log('Push Received.' ,payload);)
不明白为什么你已经在使用 setBackgroundMessageHandler以上是关于我在浏览器上时看不到 Firebase 通知的主要内容，如果未能解决你的问题，请参考以下文章
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