Firebase：在多个设备上阻止同一帐户 [英] Firebase : Prevent same account on multiple devices

问题描述

我正在开发一个有角度的应用程序，并且使用Firebase对我的用户进行身份验证。
我想知道如何防止我的用户将他们的帐户提供给其他人。
另外，我想防止人们使用同一帐户同时从不同设备登录。
我发现了一些非常不错的教程来构建在线状态系统，但是这些系统并不能阻止多个设备上的许多人使用同一帐户。
我已经能够检查某个用户是否正在尝试使用一个已经在使用的帐户（在线），但是我无法注销其中一个用户（使用一个在线帐户）。
我尝试在signInwithemailAndPassword（）方法内调用auth.signout（），但是它不起作用，我没有成功注销用户。
谢谢您的帮助。我需要的是一个摘要，因为从理论上讲，一切都非常简单。

I'm working on an angular app and I use Firebase to authenticate my users. I would like to know how I could prevent my users to give their account to other people. Also I would like to prevent people to use the same account to login from different devices at the same time. I found some very good tutorials to build a presence system, but these system doesn't prevent the same account to be used by many different people on several devices. I have been able to check if a user is trying tu use an account that is already in use (online) but I can't manage to log out one of those users (using an alreaydy online account..). I tried to call auth.signout() inside the signInwithemailAndPassword() method but it doesn't work, I don't succeed in logout the users. Thank you for your help. What I would need is a snippet because theorically, everything is very simple.

推荐答案

由于您没有说明自己使用的语言，重复使用我只是要使用Swift，但是我在这里阐述的原理对于任何语言都是相同的。

Since you didn't state what language you're using I'm just going to use Swift, but the principles behind what I laid out here are the same for any language.

看看这个问题。 Firebase似乎不直接支持您要查找的内容。但是，您可以执行以下操作：

Take a look at this question. It appears that Firebase does not directly support what you are looking for. You can however, do something like this:

在数据库中创建一棵树，该树存储用户登录的布尔值。

Create a tree in your database that stores a boolean value for user signins.

SignedIn: {
    uid1: {
        "signedIn": true
    }
    uid2: {
        "signedIn": false
    }
    .....
}

我假设在身份验证后您可以更改屏幕。现在，您需要先执行其他查询。如果用户已经登录，则可以显示警报，否则，您可以像往常一样继续操作。

I'm assuming some where after authentication you change the screen. You'll now want to perform an additional query before doing that. If the user is already signed in you can display an alert, otherwise you can just continue as you always did.

func alreadySignedIn() {
     if let uid = Auth.auth().currentUser?.uid {
        Database.database().reference().child("SignedIn").child(uid).observeSingleEvent(of: .value, with: { snap in
            if let dict = snap.value as? [String: Any] {
                if let signedIn = dict["signedIn"] as? Bool {
                    if signedIn {
                        // display an alert telling the user only one device can use
                        // there account at a time
                    }
                    else {
                        // change the screen like normal
                    }
                }
            }
        })
     }
}

当然，这只是防止帐户成为共享。如果仅允许基于设备ID登录，则可以制定更严格的准则。例如，您可以获取设备ID ，而仅允许在该设备上登录。您必须允许用户在购买新设备时对其进行更新，但是如果您确实想锁定帐户，则可能是一个更好的选择。

Of course this just prevents the account from being "shared" at the same time. You can make a stricter guideline if you only allow sign in based on a device id. For example you could get the device id and only allow sign in on that device. You'd have to allow users to update this when they get a new device, but if you really want to lock your accounts down this might be a better option.

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