ASP.NET Core 3.0 策略重定向

Question

我们拥有控制某些服务高级页面的这部分代码。 On 方法 Deny 重定向到升级页面，供没有高级会员资格的人使用。

代码在 asp.NET core 2 上运行完美，但在 asp.NET core 3 上运行失败。 context.Resource 不再是 AuthorizationFilterContext 类型，但 Endpoint 没有提供 Result 成员。

¿如何使用 asp.Net core 3 上提供的新 Enpoint 进行页面重定向？

public Task Deny(AuthorizationHandlerContext context, SubscriptionRequirement requirement)
    {
        var mvcContext = context.Resource as AuthorizationFilterContext;
        if (mvcContext == null)
            return Task.CompletedTask;

        mvcContext.Result = new RedirectToActionResult("Upgrade", "Subscription", new { ReturnUrl = _contextAccessor.HttpContext.Request.Path });
        context.Succeed(requirement);
        return Task.CompletedTask;
    }

Answer 1

根据 SOC 负责人的说法，将授权与响应重定向混为一谈似乎不是一个好习惯。

相反，您可以将授权逻辑包装到策略中，然后调用 IAuthorizationService 并随时随地重定向。

假设您定义了“高级会员”政策。然后您可以毫不费力地使用中间件/资源过滤器/操作过滤器甚至操作方法重定向请求。例如，我创建MembershipResourceFilter 如下：

public class MembershipResourceFilter : IAsyncResourceFilter
{
    public async Task OnResourceExecutionAsync(ResourceExecutingContext context, ResourceExecutionDelegate next)
    {
        var HttpContext = context.HttpContext;
        var authZ = HttpContext.RequestServices.GetRequiredService<IAuthorizationService>();
        var routeData= context.RouteData;
        var result = await authZ.AuthorizeAsync(HttpContext.User, routeData,"premium membership");
        if(!result.Succeeded)
        {
            context.Result = new RedirectToActionResult("Upgrade", "Subscription", new { ReturnUrl = HttpContext.Request.Path });
        }
        await next();
    }
}

我使用以下策略测试上述代码，它对我来说很好。

services.AddAuthorization(o =>{
    o.AddPolicy("premium membership", pb => pb
        .RequireAuthenticatedUser()
        .RequireAssertion((context)=>{
            // check current context.User has premium membership
            var user = context.User;
            var routeData = context.Resource as RouteData;
            if(routeData != null){
                try{
                    var controller = routeData.Values["controller"]?.ToString();
                    var action = routeData.Values["action"]?.ToString();
                    // now you get the route value
                    if(controller == "Home" && action == "Action"){
                        // ...
                        return true;
                    }
                }catch{
                    return false;
                }
            }
            return false;
        })
    );
});

---

[编辑]

如果您不想更改[Authorize("Premium")]，您可以创建一个简单的中间件，而不是资源过滤器：

    ...
    app.UseAuthentication();
    app.UseRouting();


    app.Use(async(ctx,next)=>{
        var ep= ctx.Features.Get<IEndpointFeature>()?.Endpoint;
        var authAttr = ep?.Metadata?.GetMetadata<AuthorizeAttribute>()
        if(authAttr!=null && authAttr.Policy == "premium membership"){
            var authService = ctx.RequestServices.GetRequiredService<IAuthorizationService>();
            var result = await authService.AuthorizeAsync(ctx.User, ctx.GetRouteData(),authAttr.Policy);
            if(!result.Succeeded)
            {
                var path = $"/Subscription/Upgrade?ReturnUrl={ctx.Request.Path}";
                ctx.Response.Redirect(path) ;
                return;
            }
        }
        await next();
    });

    app.UseAuthorization();
    app.UseEndpoints(endpoints =>{ ... });

中间件和资源过滤器基本上做同样的事情：调用授权服务并在需要时重定向。

Answer 2

我通过将IHttpContextAccessor 注入AuthorizationHandler 构造函数然后这样做来解决这个问题：

public Task Deny(AuthorizationHandlerContext context, SubscriptionRequirement requirement)
{
    //your logic here
    context.Succeed(requirement);
    return _contextAccessor.HttpContext.ExecuteResultAsync(
      new RedirectToActionResult("Upgrade", "Subscription", new { 
        ReturnUrl = _contextAccessor.HttpContext.Request.Path 
    }));
}

HttpContext.ExecuteResultAsync是一个扩展方法：

 public static class HttpContextExtensions  
{
    private static readonly RouteData EmptyRouteData = new RouteData();

    private static readonly ActionDescriptor EmptyActionDescriptor = new ActionDescriptor();

    public static Task ExecuteResultAsync<TResult>(this HttpContext context, TResult result)
        where TResult : IActionResult
    {
        if (context == null) throw new ArgumentNullException(nameof(context));
        if (result == null) throw new ArgumentNullException(nameof(result));

        var executor = context.RequestServices.GetRequiredService<IActionResultExecutor<TResult>>();

        var routeData = context.GetRouteData() ?? EmptyRouteData;
        var actionContext = new ActionContext(context, routeData, EmptyActionDescriptor);

        return executor.ExecuteAsync(actionContext, result);
    }
}

我正在使用核心 3.1，以防它有所作为。