Firebase EqualTo性能&安全 [英] Firebase EqualTo performance & security

问题描述

我有一个与用户相关的对象数组，并希望获得与一个用户相关的所有对象。我不能将userid保存为父节点，而是将其作为子节点保存，以便我想使用 equalTo 方法。

  ref.orderByChild（userid）。等于（uid）.on（child_added，function（snapshot）{
 console.log（snapshot.val ）; 
}）; 
  

这是否首先查询所有对象（慢），然后只选择所需要的对象，否则firebase会优化在服务器上查询本身？我来自SQL，我有点不确定如何处理在firebase中的查询。

编辑：还有安全问题。用户可以通过劫持js代码来接收所有对象？我希望安全规则应该解决这个问题？

示例JSON：

  {
 Objectkey1：{userid：'uid'，...}，
 Objectkey2：{userid：'uid'，...}，
 ... 
} 
  

解决方案

所有的对象（慢），然后只选择所需要的或者firebase在服务器上优化查询本身？

发生什么事情因此，当您将更多项目添加到由 ref 标识的位置时，此操作将始终变慢。

如果该类型（例如，如果您关心可扩展性），请考虑向 uid 标识的用户添加倒数/次级索引。

I have an array of objects related to users and want to get all objects related to one user. I can't save the userid as a parent node but as a child so that I want to use the equalTo method.

ref.orderByChild("userid").equalTo(uid).on("child_added", function(snapshot) {
  console.log(snapshot.val());
});

Does this first query all objects (slow) and then select only the required ones or does firebase optimize the query itself on the server? I come from SQL and I am a bit unsure how to handle where queries in firebase.

Edit: there are also security issues. A user could receive all objects by hacking the js code? I hope the security rules should solve this?

Example JSON:

{
   Objectkey1: { userid: 'uid', ... },
   Objectkey2: { userid: 'uid', ... },
   ...
}

解决方案

Does this first query all objects (slow) and then select only the required ones or does firebase optimize the query itself on the server?

Yup, that's pretty much what happens. So this operation will always get slower as you add more items to the location identified by ref.

If that type of performance is a concern (i.e. if you care about scalability), consider adding an inverted/secondary index to the thing that user identified by uid.

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