如何从 ASP.NET Core 中的 ActionFilterAttribute 访问 AppSettings [英] How can I access AppSettings from an ActionFilterAttribute in ASP.NET Core

问题描述

我目前正在尝试开发一个 WebAPI (.NET Core)，它有一些应该使用 HTTP 基本身份验证的控制器操作.为了实现这一点，我编写了一个 ActionFilterAttribute，然后我可以在我的控制器中使用它来限制对某些操作的访问.如果我做这样的事情，这一切都很好:

I am currently trying to develop a WebAPI (.NET Core) which has some controller actions that should use HTTP Basic Authentication. To implement this, I have written an ActionFilterAttribute which I can then use in my controller to restrict access to certain actions. This all workes well if I do something like this:

BasicAuthAttribute.cs

public class BasicAuthAttribute : ActionFilterAttribute{
    private string _username { get; set; }
    private string _password { get; set; }

    public BasicAuthAttribute(string username, string password) {
        _username = username;
        _password = password;
    }

    public override void OnActionExecuting(ActionExecutingContext actionContext) {
    //do Auth check...
    }
}

在控制器中，我按如下方式使用它:

In the controller I then use it as following:

SomeController.cs

[BasicAuth("testuser","testpassword")]
[HttpGet("{id}")]
public IActionResult Get(string id) {
    return new ObjectResult("Test");
}

现在我不想在 SomeController.cs 中指定用户名和密码.相反，我想将它们存储在 appsettings.json 中.如何在 ActionFilterAttribute 的 OnActionExecuting 方法中访问存储在 appsettings.json 中的值?

Now I do not want to specify username ond password in SomeController.cs. Instead I would like to store them in appsettings.json. How is it possible to access values stored in appsettings.json in the OnActionExecuting method in the ActionFilterAttribute?

如果我将 BasicAuthAttribute 的构造函数更改为以下内容，.Net 希望我通过设置，这是不可能的.依赖注入在这里似乎不起作用.

If I change the constructor of BasicAuthAttribute to the following, .Net expects me to pass the settings, which is not possible. Dependency Injection seems not to work here.

public BasicAuthAttribute(IOptions<AppSettings> appSettings) {}

任何帮助或想法将不胜感激

Any help or ideas would be appreciated

更新基于 Set 的回答:

我最终将属性更改为过滤器.如果其他人需要它，请参阅下面的工作解决方案:

I ended up changing the attribute to a filter. In case anybody else needs it see the working solution below:

BasicAuthFilter.cs

public class BasicAuthFilter : IActionFilter {

    protected AppSettings _settings { get; set; }

    public BasicAuthAttribute(IOptions<AppSettings> appSettings) {
        _settings = appSettings;
    }

    public void OnActionExecuted(ActionExecutedContext context) {
        //nothing to do here
    }

    public override void OnActionExecuting(ActionExecutingContext actionContext) 
    {
        //do Auth check...
    }
}

SomeController.cs

public class SomeController : Controller {
   [TypeFilter(typeof(BasicAuthFilter))]
   [HttpGet("{id}")]
   public IActionResult Get(string id) {
        return new ObjectResult("Test");
   }
}   

推荐答案

ASP.NET Core 文档 解释了如何使用 DI:

Filters section in ASP.NET Core documentation explains how to use DI:

如果您的过滤器具有需要从 DI 访问的依赖项，则有几种支持的方法.您可以使用以下方法之一将过滤器应用于类或操作方法:

If your filters have dependencies that you need to access from DI, there are several supported approaches. You can apply your filter to a class or action method using one of the following:

• ServiceFilterAttribute
• TypeFilterAttribute
• IFilterFactory 在您的属性上实现
• ServiceFilterAttribute
• TypeFilterAttribute
• IFilterFactory implemented on your attribute

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