将服务注入行动过滤器 [英] Inject service into Action Filter

问题描述

我试图在我的动作过滤器中注入一个服务，但是我没有在构造函数中注入所需的服务。这是我有的：

  public class EnsureUserLoggedIn：ActionFilterAttribute 
 {
 private readonly ISessionService _sessionService; 
 
 public EnsureUserLoggedIn（）
 {
 //由于编译错误而使用
 /我无法删除默认的ctor 
 // /属性在我的控制器
} 
 
 public EnsureUserLoggedIn（ISessionService sessionService）
 {
 _sessionService = sessionService; 
} 
 
 public override void OnActionExecuting（ActionExecutingContext context）
 {
 //问题：_sessionService为null这里
 if（_sessionService.LoggedInUser == null ）
 {
 context.HttpContext.Response.StatusCode =（int）HttpStatusCode.Unauthorized; 
 context.Result = new JsonResult（Unauthorized）; 
} 
} 
} 
  

我正在装饰我的控制器如下所示：

  [Route（api / issues），EnsureUserLoggedIn] 
 public class IssueController：Controller 
 {
} 
  

Startup.cs

  services.AddScoped< ISessionService，SessionService>（）; 
  

解决方案

使用这些文章作为参考：

ASP.NET Core 1.0动作过滤器

ASP.NET 5和MVC 6中的动作过滤器，服务过滤器和类型过滤器

过滤器作为ServiceFilter

由于过滤器将用作 ServiceType ，因此需要注册框架IoC。如果直接使用操作过滤器，则不需要。

Startup.cs

  public void ConfigureServices（IServiceCollection services）{
 services.AddMvc（）; 
 
 services.AddScoped< ISessionService，SessionService>（）; 
 services.AddScoped< EnsureUserLoggedIn>（）; 
 
 ... 
} 
  

自定义过滤器被添加到MVC控制器方法和控制器类使用 ServiceFilter 属性，如下所示：

  [ServiceFilter（typeof（EnsureUserLoggedIn））] 
 [Route（api / issues）] 
 public class IssueController：Controller {
 // GET：api / issues 
 [HttpGet] 
 [ServiceFilter（typeof（EnsureUserLoggedIn））] 
 public IEnumerable< string> Get（）{...} 
} 
  

还有其他例子

• 使用过滤器作为全局过滤器




• 使用过滤器使用基本控制器




• 使用具有订单的过滤器

看看，请试试看看是否解决了你的问题。

希望这有帮助。

I am trying to inject a service into my action filter but I am not getting the required service injected in the constructor. Here is what I have:

public class EnsureUserLoggedIn : ActionFilterAttribute
{
    private readonly ISessionService _sessionService;

    public EnsureUserLoggedIn()
    {
        // I was unable able to remove the default ctor 
        // because of compilation error while using the 
        // attribute in my controller
    }

    public EnsureUserLoggedIn(ISessionService sessionService)
    {
        _sessionService = sessionService;
    }

    public override void OnActionExecuting(ActionExecutingContext context)
    {
        // Problem: _sessionService is null here
        if (_sessionService.LoggedInUser == null)
        {
            context.HttpContext.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
            context.Result = new JsonResult("Unauthorized");
        }
    }
}

And I am decorating my controller like so:

[Route("api/issues"), EnsureUserLoggedIn]
public class IssueController : Controller
{
}

Startup.cs

services.AddScoped<ISessionService, SessionService>();

解决方案

Using these articles as reference:

ASP.NET Core 1.0 Action Filters

Action filters, service filters and type filters in ASP.NET 5 and MVC 6

Using the filter as a ServiceFilter

Because the filter will be used as a ServiceType, it needs to be registered with the framework IoC. If the action filters were used directly, this would not be required.

Startup.cs

public void ConfigureServices(IServiceCollection services) {
    services.AddMvc();

    services.AddScoped<ISessionService, SessionService>();
    services.AddScoped<EnsureUserLoggedIn>();

    ...
}

Custom filters are added to the MVC controller method and the controller class using the ServiceFilter attribute like so:

[ServiceFilter(typeof(EnsureUserLoggedIn))]
[Route("api/issues")]
public class IssueController : Controller {
    // GET: api/issues
    [HttpGet]
    [ServiceFilter(typeof(EnsureUserLoggedIn))]
    public IEnumerable<string> Get(){...}
}

There were other examples of

• Using the filter as a global filter

• Using the filter with base controllers

• Using the filter with an order

Take a look, give them a try and see if that resolves your issue.

Hope this helps.

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