尚未使用WebApi Delegating处理程序分配内部处理程序

Question

我在我的代码中遇到WebApi抛出异常的问题:

public class WebApiAuthenticationHandler : DelegatingHandler
    {
        private const string AuthToken = "AUTH-TOKEN";

        protected override Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request, CancellationToken cancellationToken)
        {                  
            var requestAuthTokenList = GetRequestAuthTokens(request);
            if (ValidAuthorization(requestAuthTokenList))
            {
                // EXCEPTION is occuring here!....
                return base.SendAsync(request, cancellationToken);
            }

            /*
            ** This will make the whole API protected by the API token.
            ** To only protect parts of the API then mark controllers/methods
            ** with the Authorize attribute and always return this:
            **
            ** return base.SendAsync(request, cancellationToken);
            */
            return Task<HttpResponseMessage>.Factory.StartNew(
                () =>
                {
                    var resp = new HttpResponseMessage(HttpStatusCode.Unauthorized)
                    {
                        Content = new StringContent("Authorization failed")
                    };

                    //var resp = new HttpResponseMessage(HttpStatusCode.Unauthorized);                                                                                   
                    //resp.Headers.Add(SuppressFormsAuthenticationRedirectModule.SuppressFormsHeaderName,"true");
                    return resp;
                });
        }

例外情况发生在线上:

base.SendAsync(request, cancellationToken);

我不知道如何解决这个问题.我的路由表中有以下内容:

    routes.MapHttpRoute("NoAuthRequiredApi", "api/auth/", new { Controller = "Auth" });
    routes.MapHttpRoute("DefaultApi", "api/{controller}/{id}", new { id = RouteParameter.Optional }, null, new WebApiAuthenticationHandler());

发生这种情况的路线是DefaultApi路线.任何帮助非常感谢....

Answer 1

找到答案在这里和实例句柄在这里.

您需要设置希望传递请求的InnerHandler.

只需将其添加到构造函数中:

public class WebApiAuthenticationHandler : DelegatingHandler
{
    public WebApiAuthenticationHandler(HttpConfiguration httpConfiguration)
    {
        InnerHandler = new HttpControllerDispatcher(httpConfiguration); 
    }

并在创建新实例时传递对GlobalConfiguration的引用:

routes.MapHttpRoute("DefaultApi", "api/{controller}/{id}", new { id = RouteParameter.Optional }, null, WebApiAuthenticationHandler(GlobalConfiguration.Configuration));

Answer 2

正如丹尼尔·罗斯（Daniel Roth）在当前投票最高的答案的链接中提到的，您的处理程序链不得以.DelegatingHandler

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DelegatingHandler \xe2\x80\x9cdelegates\xe2\x80\x9d 对使用 InnerHandler 属性提供的内部处理程序的发送调用。DelegatingHandler 用于将俄罗斯娃娃模型中的消息处理程序链接在一起。错误消息表明未提供 InnerHandler。通常在客户端上，您希望最内部的处理程序是 HttpClientHandler ，它将发送请求并处理响应。

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解决该错误的最简单方法是使用构造函数重载进行设置，InnerHandler如下所示：

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public class CustomHandler : DelegatingHandler\n{\n    public CustomHandler()\n        : base(new HttpClientHandler())\n    {\n    }\n}\n

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没有必要传入 anHttpConfiguration并将其包装在 an 中HttpControllerDispatcher。

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