Javascript Firebase getToken() TypeError：无法读取属性
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/37934898/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Firebase getToken() TypeError: Cannot read property
提问by thousight
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:
我正在尝试获取我网站当前登录用户的令牌。但是，javascript 无法为我获取价值。我认为这里有两个问题：
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.
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?
当我在开始时获取 Auth.currentUser 时，出现“TypeError：无法读取 null 的属性‘getToken’”的错误。但是当我在控制台中输入 Auth.currentUser.getToken() 时，带有令牌的对象实际上出现了。
getToken() 返回给我的是一个 promise 对象，其键 'ea' 包含令牌的值。但是当我做 Auth.currentUser.getToken().ea 它让我'空'。如何直接从对象中检索令牌？
Thanks!
谢谢！
My code of retrieving the token:
我检索令牌的代码：
var Auth = firebase.auth()
var token = Auth.currentUser.getToken()
This screenshot might be helpful:
此屏幕截图可能会有所帮助：
回答by Frank van Puffelen
According to the documentation of firebase.User:getIdToken():
根据以下文件firebase.User:getIdToken()：
Returns a JWT token used to identify the user to a Firebase service.
Returns the current token if it has not expired, otherwise this will refresh the token and return a new one.
将用于向 Firebase 服务标识用户的 JWT 令牌返回。
如果未过期，则返回当前令牌，否则将刷新令牌并返回一个新令牌。
The method returns a promise, since it may require a round-trip to the Firebase servers in case the token has expired:
该方法返回一个承诺，因为如果令牌已过期，它可能需要往返于 Firebase 服务器：
Auth.currentUser.getIdToken().then(data => console.log(data))
Or in more classic JavaScript:
或者在更经典的 JavaScript 中：
Auth.currentUser.getIdToken().then(function(data) {
console.log(data)
});
Log output:
日志输出：
ey...biPA
眼睛...双PA
Update: to ensure that the user is signed in before getting the token, run the above code in an onAuthStateChangedlistener:
更新：为确保用户在获取令牌之前已登录，请在onAuthStateChanged侦听器中运行上述代码：
firebase.auth().onAuthStateChanged(function(user) {
if (user) {
user.getIdToken().then(function(data) {
console.log(data)
});
}
});
回答by Yang
Here is a sample on how to get the id token using NodeJS
这是一个关于如何使用 NodeJS 获取 id 令牌的示例
var firebase = require('firebase')
firebase.initializeApp({
apiKey:*********
databaseURL:*********
})
var customToken = *********
firebase.auth().signInWithCustomToken(customToken).catch(function(error) {
var errorMessage = error.message
console.log(errorMessage)
})
firebase.auth().onAuthStateChanged(function(user) {
if (user) {
firebase.auth().currentUser.getToken().then(data => console.log(data))
} else {
console.log('onAuthStateChanged else')
}
})
