Firebase 数据库规则 - 检查初始子值答案

【问题标题】：Firebase database rule - Check for initial child valuesFirebase 数据库规则 - 检查初始子值
【发布时间】：2020-12-05 23:20:51
【问题描述】：

一个用户只有在他有正确的孩子和正确的初始值时才应该被创建。

以下代码有效，但它阻止我在创建用户后更改健康值。

如何仅检查初始子值？

{
    "rules": {
        ".read": true,
            ".write": false,
                "users": {
            // Only allow writes in users
            ".write": true,
                "$user": {
                // Check if new user has the correct children
                ".validate": "newData.hasChildren(['userID', 'deviceModel', 'health', 'age', 'playername', 'score', 'clickedby', 'timestamp'])
                    // Check if new user has a health of 10
                    && newData.child('health').val() == '10'
                    // Check if new user has an age of 0
                    && newData.child('age').val() == '0'
                    // Check if new user has a score of 0
                    && newData.child('score').val() == '0'
                    // Check if new user has a timestamp which is not a future value
                    && newData.child('timestamp').val() <= now"
            }
        }
    }
}

更新：Frank van Puffelen 的规则完美运行

这是我更新后的规则：

{
    "rules": {
        ".read": true,
            ".write": false,
                "users": {
            // Only allow writes in users
            ".write": true,
                "$user": {
                // Check if new user has the correct children
                ".validate": "data.exists() || (
                newData.hasChildren(['userID', 'deviceModel', 'health', 'age', 'playername', 'score', 'clickedby', 'timestamp'])
                    // Check if new user has a health of 10
                    && newData.child('health').val() == 10
                    // Check if new user has an age of 0
                    && newData.child('age').val() == 0
                    // Check if new user has a score of 0
                    && newData.child('score').val() == 0
                    // Check if new user has a timestamp which is not a future value
                    && newData.child('timestamp').val() <= now) "
            }
        }
    }
}

【问题讨论】：

标签： firebase-realtime-database firebase-security

【解决方案1】：

如果您只想检查新数据，可以使用data.exist()。例如：

".validate": "data.exists() || (
  newData.hasChildren(['userID', 'deviceModel', 'health', 'age', 'playername', 'score', 'clickedby', 'timestamp'])
    // Check if new user has a health of 10
    && newData.child('health').val() == '10'
    // Check if new user has an age of 0
    && newData.child('age').val() == '0'
    // Check if new user has a score of 0
    && newData.child('score').val() == '0'
    // Check if new user has a timestamp which is not a future value
    && newData.child('timestamp').val() <= now
 )"

不相关：我会考虑将数值存储在数字中，而不是像现在这样存储在字符串值中。那就是newData.child('health').val() == 10 等等。

顺便说一句：在开发早期编写如此漂亮的安全规则值得称赞。 ?

【讨论】：

非常感谢弗兰克！您的规则完美运行。我唯一要做的就是将最后一个 ) 移到最后一个“像这样：