Firebase getToken()TypeError:无法读取属性 [英] Firebase getToken() TypeError: Cannot read property

问题描述

我正在尝试获取我当前登录的网站用户的令牌.但是，javascript无法为我带来价值.我认为这里有2个问题:

I'm trying to get the token of my currently signed in user of my website. However, javascript cannot get the value for me. I think there are 2 problems here:

1. 当我在开始时获得Auth.currentUser时，出现以下错误"TypeError:无法读取null的属性'getToken'".但是，当我在控制台中键入Auth.currentUser.getToken()时，实际上会显示带有令牌的对象.

1. When I'm getting Auth.currentUser at start, I get this error of "TypeError: Cannot read property 'getToken' of null". But when I type Auth.currentUser.getToken() in the console, the object with the token actually shows up.

getToken()返回给我的是一个承诺对象，其键"ea"包含令牌的值.但是当我执行Auth.currentUser.getToken().ea时，它使我为"null".如何直接从对象中检索令牌?

What getToken() returns to me is a promise object with its key 'ea' containing the value of the token. but when I do Auth.currentUser.getToken().ea it gets me 'null'. How can I retrieve the token directly from the object?

谢谢！

我获取令牌的代码:

var Auth = firebase.auth()
var token = Auth.currentUser.getToken()

此屏幕截图可能会有所帮助:

This screenshot might be helpful:

推荐答案

根据

According to the documentation of firebase.User:getIdToken():

将用于标识用户的JWT令牌返回到Firebase服务.

Returns a JWT token used to identify the user to a Firebase service.

如果当前令牌尚未过期，则返回该令牌，否则将刷新该令牌并返回一个新令牌.

Returns the current token if it has not expired, otherwise this will refresh the token and return a new one.

该方法返回一个promise，因为如果令牌过期，它可能需要往返Firebase服务器:

The method returns a promise, since it may require a round-trip to the Firebase servers in case the token has expired:

Auth.currentUser.getIdToken().then(data => console.log(data))

或更经典的JavaScript:

Or in more classic JavaScript:

Auth.currentUser.getIdToken().then(function(data) {
    console.log(data)
});

日志输出:

ey ... biPA

ey...biPA

更新:要确保用户在获取令牌之前已登录，请在

Update: to ensure that the user is signed in before getting the token, run the above code in an onAuthStateChanged listener:

firebase.auth().onAuthStateChanged(function(user) {
  if (user) {
    user.getIdToken().then(function(data) {
      console.log(data)
    });
  }
});

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