Question

我有一个云功能，每当有新消息写入与该用户相关联的数据库时，它都会向接收者发送通知。我似乎总是出错。

我是云功能的新手，似乎无法解决此问题。

请参阅下面的云功能

exports.sendNotification = functions.database.ref('/messages/{userId}/{messageId}')
.onWrite((snapshot,context) => {
    
    //get the userId of the person receiving the notification because we need to get their token
    const receiverId = context.params.userId;
    console.log("receiverId: ", receiverId);
    
    //get the user id of the person who sent the message
    //const senderId = context.data.child('senderUid').val();
    const senderId = snapshot.data.child('senderUid').val();
    console.log("senderId: ", senderId);
    
    //get the message
    const message = snapshot.data.child('messageBody').val();
    console.log("message: ", message);
    
    //get the message id. We'll be sending this in the payload
    const messageId = context.params.messageId;
    //const messageId = event.params.messageId;
    console.log("messageId: ", messageId);
    
    //query the users node and get the name of the user who sent the message
    return admin.database().ref("/Renters/" + senderId).once('value').then(snap => {
        const senderName = snap.child("houseName").val();
        console.log("senderName: ", senderName);
        
        //get the token of the user receiving the message
        return admin.database().ref("/users/" + receiverId).once('value').then(snap => {
      //const token = snap.child("messaging_token").val();
      const token = event.data.child('receiverToken').val();
            console.log("token: ", token);
            
            //we have everything we need
            //Build the message payload and send the message
            console.log("Construction the notification message.");
            const payload = {
                data: {
                    data_type: "direct_message",
                    title: "New Message from " + senderName,
                    message: message,
                    message_id: messageId,
                }
            };
            
            return admin.messaging().sendToDevice(token, payload)
                        .then(function(response) {
              console.log("Successfully sent message:", response);
              //using this return statement to avoid error
              return response.successCount;
                          })
                          .catch(function(error) {
                            console.log("Error sending message:", error);
                          });
        });
    });
});

Answer 1

我已经进行了一些测试，并且data对象中的documentation没有属性DataSnapshot。由于此调用，它将赋予undefined值。因此，如果您对此进行任何调用，都会导致此类错误。

如果将...snapshot.data.child('senderUid').val()...更改为：

...snapshot.child('senderUid').val()...

不确定为什么要在此处添加此data，但是即使在引用的路径中有名为“ data”的子元素，它也无法正常工作。

触发云函数时出现“ TypeError：无法读取未定义的属性'child'”

1 个答案: