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等待承诺Angular 2

[英]Wait to Promise Angular 2

原文 2017-08-09 13:29:27 6 2 angular/ typescript/ promise/ angular-promise

First of all I want to explain that I have read a lot of answers, and I understand that it's wrong to block the thread to wait a response. 首先，我想解释一下我已经阅读了很多答案，并且我了解阻止线程等待响应是错误的。 But I have an issue that is not that simple to solve. 但是我有一个问题并不容易解决。

I have an advanced project, where I have a function on a session service that is getAuthenticationKey():string I have used it a lot from differents parts of the code (to call rest functions, etc.), and I made it as an ordinary function because I thought that this value will be there or not. 我有一个高级项目，其中在会话服务上有一个功能为getAuthenticationKey():string我在代码的不同部分（例如调用剩余函数等）使用了很多功能，并将其作为普通函数，因为我认为此值将存在或不存在。

Now we have made some changes, and the getAuthenticationKey will have to call a rest function to refresh the key if it's necessary. 现在我们进行了一些更改，如果必要， getAuthenticationKey将必须调用rest函数来刷新密钥。

So the problem is that I understand that the best way to do that is to make a promise and refactor the whole project, but this is too expensive in terms of hours, because I have to make promises for that function and all others that depends of that function (almost all the application), and considering that the refresh is a fast operation and is called once a day or a week, there is any way to fix this without refactoring all the project? 因此，问题在于，我了解做到这一点的最佳方法是做出承诺并重构整个项目，但这在小时数方面太昂贵了，因为我必须对该功能以及所有其他依赖于此的功能做出承诺。该功能（几乎所有应用程序），并且考虑到刷新是一项快速操作，并且每天或每周调用一次，是否有任何方法可以解决此问题而无需重构所有项目？

2 个解决方案

You can probably keep your code as it is, just add a periodic checker ( setInterval(...) ) that will update the authenticationKey if necessary. 您可能可以保持您的代码不变，只需添加一个定期检查器（ setInterval(...) ），该检查器将在必要时更新authenticationKey 。 If you know the lifetime of the key, you can just use setTimeout(...) instead of periodic checking. 如果知道密钥的生存期，则可以只使用setTimeout(...)而不是定期检查。

I solve this problem using a Resolver, since I check the authentication when a page is loaded. 我使用解析器解决了此问题，因为我在加载页面时检查身份验证。 In the resolver I check the auth against a rest service and store the result in a service. 在解析器中，我针对其余服务检查身份验证，并将结果存储在服务中。