c# - 如何访问 ASP.NET Core 服务中的路由数据/值提供程序数据？

Question

我正在尝试写一个 Policy-based Authorization Handler . handler的业务逻辑需要使用默认路由传入的当前请求的记录id。

[Authorize(Roles = "TaskAdmin", Policy = "RecordOwner")]
public IActionResult Index(int id) // <-- Need this id
{
    // <snip>

    return View();
}

政策

这是我需要访问 id 路由值的类。

public class RecordOwnerHandler : AuthorizationHandler<RecordOwnerRequirement>
{
    private readonly ApplicationDbContext dbContext;

    public RecordOwnerHandler(ApplicationDbContext dbContext)
    {
        this.dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext));
    }

    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, RecordOwnerRequirement requirement)
    {
        if (IsUserAuthorized(context))
        {
            context.Succeed(requirement);
        }

        //TODO: Use the following if targeting a version of
        //.NET Framework older than 4.6:
        //      return Task.FromResult(0);
        return Task.CompletedTask;
    }

    private bool IsUserAuthorized(AuthorizationHandlerContext context)
    {
        //****************************************
        // Need the id here...
        //****************************************

        // Return the result
        return true;
    }
}

启动

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    services.AddIdentity<ApplicationUser, IdentityRole>()
        .AddEntityFrameworkStores<ApplicationDbContext>()
        .AddDefaultTokenProviders();

    // *** Add policy for record owner ***
    services.AddAuthorization(options =>
    {
        options.AddPolicy("RecordOwner", policy =>
            policy.Requirements.Add(new RecordOwnerRequirement()));
    });

    // Add application services.
    services.AddTransient<IEmailSender, EmailSender>();

    // *** Register record owner handler with the DI container ***
    services.AddTransient<IAuthorizationHandler, RecordOwnerHandler>(); 

    services.AddMvc();
}

我尝试了什么

1. 我尝试使用 IHttpContextAccessor 作为 RecordOwnerHandler 的构造函数参数，但是 IHttpContextAccessor.HttpContext 似乎不包含请求的 RouteData。

2. 我进行了几次 Google 搜索，看看是否有任何关于如何执行此操作的信息，但结果一无所获。

3. 然后我研究了Routing 和Model Binding 的源代码，但似乎找不到用于注入(inject)路由值的抽象进入服务。

I realize I could try to parse this info out of the URL, but I am hoping for a cleaner way to get the value.

那么，如何在 ASP.NET Core 2.0 的服务中访问路由值和/或值提供者数据？

Answer 1

可以使用 ActionContextAccessor class 访问路由值.

直接投资注册

services.AddSingleton<IActionContextAccessor, ActionContextAccessor>();

用法

public class RecordOwnerHandler : AuthorizationHandler<RecordOwnerRequirement>
{
    private readonly ApplicationDbContext dbContext;
    private readonly IActionContextAccessor actionContextAccessor;

    public RecordOwnerHandler(ApplicationDbContext dbContext, IActionContextAccessor actionContextAccessor)
    {
        this.dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext));
        this.actionContextAccessor = actionContextAccessor ?? throw new ArgumentNullException(nameof(actionContextAccessor));
    }

    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, RecordOwnerRequirement requirement)
    {
        if (IsUserAuthorized(context))
        {
            context.Succeed(requirement);
        }

        //TODO: Use the following if targeting a version of
        //.NET Framework older than 4.6:
        //      return Task.FromResult(0);
        return Task.CompletedTask;
    }

    private bool IsUserAuthorized(AuthorizationHandlerContext context)
    {
        // Now the id route value can be accessed directly...
        var id = this.actionContextAccessor.ActionContext.RouteData.Values["id"];

        // Use the dbContext to compare the id against the database...

        // Return the result
        return true;
    }
}

NOTE: I would still like to find out a way to access the value providers to do this, so it wouldn't matter if the parameter is passed through route values, query string, form values, etc.