Question

我想在Android上以Lapit Chat的形式建立聊天，我正在编写此node.js脚本并将其部署：

'use strict'

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();

exports.sendNotification = functions.database.ref('/notifications/{user_id}/{notification_id}').onWrite((change, context) => {


  const user_id = change.params.user_id;
  const notification_id = change.params.notification_id;

  console.log('We have a notification from : ', user_id);


  if (!change.after.val()) {
return console.log('A notification has been deleted from database: ', notification_id);
 }


  const fromUser = admin.database().ref(`/notifications/${user_id}/${notification_id}`).once('value');

  return fromUser.then(fromUserResult => {

    const from_user_id = fromUserResult.val().from;

    console.log('You have new notification from  : ', from_user_id);



    const userQuery = admin.database().ref(`Users/${from_user_id}/name`).once('value');
    const deviceToken = admin.database().ref(`/Users/${user_id}/device_token`).once('value');

    return Promise.all([userQuery, deviceToken]).then(result => {

      const userName = result[0].val();
      const token_id = result[1].val();


      const payload = {
        notification: {
          title : "New Friend Request",
          body: `${userName} has sent you request`,
          icon: "default",
          click_action : "com.example.ragha.safeheartchatting_TARGET_NOTIFICATION"
        },
        data : {
          from_user_id : from_user_id
        }
      };



      return admin.messaging().sendToDevice(token_id, payload).then(response => {

        return console.log('This was the notification Feature');

      });

    });

  });

});

运行应用程序并在firebase云上发送请求后，出现错误，它出现在firebase数据库中，但没有出现在移动android上

TypeError：无法读取未定义的属性“ user_id” 在exports.sendNotification.functions.database.ref.onWrite.event（/user_code/index.js:12:31）在cloudFunctionNewSignature（/user_code/node_modules/firebase-functions/lib/cloud-functions.js:105:23）在cloudFunction（/user_code/node_modules/firebase-functions/lib/cloud-functions.js:135:20）在/var/tmp/worker/worker.js:768:24 在process._tickDomainCallback（internal / process / next_tick.js：135：7）

Answer 1

如果要使用通配符的值，请使用context，而不要使用change。 change仅描述触发您的函数调用的数据库更改。

const user_id = context.params.user_id;
const notification_id = context.params.notification_id;

您应该read the documentation for database triggers来学习API。

Firebase功能：类型错误：无法读取未定义的属性“ user_id”

1 个答案: