在Firebase安全规则中的更新上使用newData

问题描述

在执行更新操作时，在Firebase安全规则中使用newData时遇到问题.

I'm having issues using newData within Firebase security rules when doing a update operation.

这是我的数据结构:

这是我的规则:

{
  "rules": {
    "videos": {
        "$videoId": {
            "data": {
                "content": {
                    "srcURL": {
                        ".write": "root.child('videos/' + $videoId + '/tokens/' + newData.child('/videos/-1vidid/requestToken').val() + '/read' ).exists()"
                    },
                },
                "meta": {
                    "status": {
                        ".write": "root.child('videos/' + $videoId + '/tokens/testTok/read').exists()"
                    }
                }
            },
            "requestToken": {
                ".write": true,
            }
        }
    }
  }
}

这是我要通过更新写入的数据:

Here is data I'm trying to write via update:

 {
  "videos/-1vidid/data/meta/status": "uploaded", 
  "videos/-1vidid/data/content/srcURL": "https",
  "videos/-1vidid/requestToken": "testTok"
  }

这是我尝试使用newData时失败的规则；

And here are my rules failing when I try to use newData;

请注意，当我在令牌("testTok")中进行硬编码时，它可以工作，但是当我尝试使用newData时，它将无法清除.

Notice it's working when I hardcode in the token ("testTok"), but when I try and use newData it won't clear.

当我从newData子级中删除"videos"和$ videoId(-1vidid")时，还有更多尝试:

Here are more attempts when I get rid of the "videos" and $videoId ("-1vidid) from the newData childs:

任何想法为何newData似乎都无法进行更新?

Any idea why newData does not appear to be working on updates?

推荐答案

您的相关规则:

root.child('videos/' + $videoId + '/tokens/' + newData.child('/videos/-1vidid/requestToken').val() + '/read' ).exists()"

newData变量引用当前位置的新数据.在您定义规则的位置下没有子/videos.

The newData variable refers to the new data at the current location. There is no child /videos under the location where you've defined the rule.

我假设您想从根开始阅读.在这种情况下，您可以使用root(在根目录中提供现有数据)，也可以使用newData.parent().parent()...(对于需要进行的多个级别重复该操作)来获取更新的数据.

I assume you want to start reading from the root. In that case you can either use root, which gives you the existing data at the root, or use newData.parent().parent()... (repeated for however many levels up you need to go) for getting the updated data.

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