我正在尝试从 Cloud 功能中过滤firebase数据库中的一些数据 . 该数据如下所示：
"items": {
"id1": {
"status": {
"creation": timestampValue,
"status": "initialized"
},
"data" : data1
}
"id2": {
"status": {
"status": "loaded"
},
"data" : data2
},
"id2": {
"status": {
"creation": timestampValue,
"status": "loaded"
},
"data" : data
},
"id3": {
"status": {
"creation": timestampValue,
"status": "ended"
},
"data" : data3
}
}
我想使用基于创建字段的过滤器 . 该领域并不总是存在 .
我的代码受这个启发：https://github.com/firebase/functions-samples/blob/master/delete-old-child-nodes/functions/index.js
这是我写的代码：
const CUT_OFF_TIME = 24 * 60 * 60 * 1000; // 24 Hours in milliseconds.
exports.cleanAfter24h = functions.database.ref('/items/{itemId}').onUpdate((change, event) => {
const ref = change.after.ref.parent; // reference to the parent
const now = Date.now();
const cutoff = now - CUT_OFF_TIME;
const oldItemsQuery = ref.orderByChild('creation').endAt(cutoff);
return oldItemsQuery.once('value').then((snapshot) => {
// create a map with all children that need to be removed
const updates = {};
snapshot.forEach(child => {
let childData = child.val();
if (childData.status.creation) {
let elapsed = childData.status.creation - cutoff;
if (elapsed <= 0) {
updates[child.key] = null;
}
} else {
console.log(child.key + ' does not have a creation date');
}
});
// execute all updates in one go and return the result to end the function
return ref.update(updates);
});
});
运行代码时，将检索所有项目，即使是时间戳小于截止值的项目以及没有创建字段的项目 . 任何建议如何解决？
我尝试删除没有创建字段的项目，方法是在endAt之前添加startAt（“”），如下所示：Firebase, query with "a child exists" as a condition?
const oldItemsQuery = ref.orderByChild('creation')startAt("").endAt(cutoff);
这样做我在查询响应中没有结果 .
1 回答
改变这个：
进入这个：