将用户添加到Firebase时，在Javascript中注册时，从Go admin后端获取消息令牌

import firebase from 'firebase/app';
import 'firebase/messaging';

if (!firebase.apps.length) {
  firebase.initializeApp({
    apiKey: "YOUR_API_KEY",
    projectId: "YOUR_PROJECT_ID",
    appId: "YOUR_APP_ID",
    messagingSenderId: "YOUR_MESSAGING_SENDER_ID",
    appId: "YOUR_APP_ID"
  });
}

const messaging = firebase.messaging();

messaging.requestPermission()
  .then(() => {
    console.log('Notification permission granted.');
    return messaging.getToken();
  })
  .then((token) => {
    console.log('FCM Token:', token);
    // 将 token 发送到后端
    sendTokenToServer(token);
  })
  .catch((err) => {
    console.log('Unable to get permission to notify.', err);
  });

function sendTokenToServer(token) {
  fetch('/api/save-token', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ token })
  })
  .then(response => response.json())
  .then(data => {
    console.log('Token saved:', data);
  })
  .catch((error) => {
    console.error('Error saving token:', error);
  });
}

package main

import (
  "encoding/json"
  "log"
  "net/http"
)

type TokenRequest struct {
  Token string `json:"token"`
}

func saveTokenHandler(w http.ResponseWriter, r *http.Request) {
  var req TokenRequest
  err := json.NewDecoder(r.Body).Decode(&req)
  if err != nil {
    http.Error(w, err.Error(), http.StatusBadRequest)
    return
  }

  token := req.Token
  // 保存 token 到数据库或进行其他处理
  log.Println("Saved token:", token)

  w.WriteHeader(http.StatusOK)
  w.Write([]byte("Token saved successfully"))
}

func main() {
  http.HandleFunc("/api/save-token", saveTokenHandler)
  log.Fatal(http.ListenAndServe(":8080", nil))
}