Question

我想向特定设备发送通知，所以我编写了此功能及其功能，但是用户名中未定义

日志输出：

获取此

after: { '-LhjfwZeu0Ryr6jYRq5r': { Price: '888', date: '2019-6-19', description: 'Ghh', id: 50, nameOfProblem: 'Vbh', providerName: 'Loy', providerService: 'Carpenter', statusInfo: 'Incomplete', time: '15:22', username:"devas" }}

username是undefined

这是功能

exports.sendPushR = functions.database.ref('/request/{pid}/{uid}/orders')
    .onWrite(async (snapshot, context) => {
        const registrationTokens = "------";
        const providerId = context.params.pid;
        const userId = context.params.uid;
        const event = context.params;
        console.log("event", event);
        console.log(`New Order from ${userId} to ${providerId}`);
        const afterData = snapshot.after.val(); // data after the write
        const username = snapshot.after.val().username;
        console.log(afterData);
        console.log(username);
        const payload = {
            notification: {
                title: 'Message received',
                body: `You received a new order from ${username} check it now! `,
                sound: "default",
                icon: "default",
            }
        };


        try {
            const response = await admin.messaging().sendToDevice(registrationTokens, payload);
            console.log('Successfully sent message:', response);
        }
        catch (error) {
            console.log('Error sending message:', error);
        }
        return null;
    });

Answer 1

由于要检索的对象具有生成的成员，因此可以使用for-in循环来检索值。

const object = snapshot.after.val()
for(const key in object) {
    if (object.hasOwnProperty(key)) {
        const element = object[key];
        if(element.username) {
             console.log(element.username);
             break;
        }  
    }
}

Answer 2

当新订单添加到数据库中时，您编写的代码似乎可以运行。但是您已经声明要像这样触发：

exports.sendPushR = functions.database.ref('/request/{pid}/{uid}/orders')
    .onWrite(async (snapshot, context) => {

这意味着，只要在用户的orders节点下写入任何内容，该代码就会触发。要仅在该orders节点下写入订单时触发，请将触发定义为：

exports.sendPushR = functions.database.ref('/request/{pid}/{uid}/orders/{orderid}')
    .onWrite(async (snapshot, context) => {

上面的区别是该路径现在包含{orderid}，这意味着它将触发树的下一级，而您的snapshot.after将不再包含-L级别。

由于您实际上似乎只在乎订单的创建时间，因此您也只能对此进行触发（这意味着在更新或删除订单时不会调用您的函数）。就像这样：

exports.sendPushR = functions.database.ref('/request/{pid}/{uid}/orders/{orderid}')
.onCreate(async (snapshot, context) => {
    ...
    const afterData = snapshot.val();
    const username = snapshot.val().username;
    console.log(afterData);
    console.log(username);
    ...
});

在这里，我们再次在JSON的较低级别上触发。但是由于现在我们触发了onCreate，所以我们不再有前后快照，而只需执行snapshot.val()即可获取刚刚创建的数据。

云功能中未定义的用户名？

2 个答案: