在Firebase Firestore中实施唯一的userId [英] Enforcing unique userIds in Firebase Firestore

问题描述

我正在使用Firebase的新Firestore数据库，并想知道是否存在一种更有效的方法来实施唯一的用户名(或唯一的子节点).

I'm playing around with the new Firestore database from Firebase and was wondering if there was a more efficient way to enforce unique usernames (or unique child nodes).

我使用电子邮件/密码身份验证，但允许用户创建唯一的句柄，例如Twitter.

I use email/password auth but allow users to create a unique handle, like Twitter.

借助实时数据库，我能够通过事务和多节点结构实现这一目标.

With the Realtime database I was able to achieve this with transactions and a multiple node structure.

-users
    -uid1234:
        -username: ryan

-usernames:
    -ryan: uid1234

我当时在想，如果没有多余的 usernames 节点(使用文档作为Firestore中的用户名)，则有可能做到这一点.

I was thinking it may be possible to do this without the extra usernames node using documents as the username in Firestore.

推荐答案

您可能可以通过2种方法来做到这一点.创建用户之前，请先与另一个呼叫联系，以确认该用户是否存在于具有用户名的集合中.

You could do it probably do it in 2 ways. Check with a separate call before create user, if the user exist in an collection with usernames.

您还可以创建类似以下规则:

Also you could create a rule like:

match /users/{document=**} {
    allow create: if !exists(/databases/$(database)/documents/usernames/$(request.resource.data.username));
}

在这种情况下，如果用户名在创建时已经存在并且您可以捕获代码，则会返回一个错误.

In that case you get a error back if the username already exist on creating and that you can catch in the code.

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