asp.net - HttpWebRequest 抛出 404 异常

Question

我发现 HttpWebRequest 对不存在的资源抛出 WebException。在我看来，这很奇怪，因为 HttpWebResponse 有 StatusCode 属性(NotFount 项存在)。您认为这有什么原因吗？或者这只是开发人员的问题？

var req = (HttpWebRequest)WebRequest.Create(someUrl);
using (HttpWebResponse response = (HttpWebResponse)req.GetResponse()) {
    if (response.StatusCode == HttpStatusCode.OK) { ...}
}

Answer 1

这确实是一个令人沮丧的问题，可以通过使用以下扩展方法类并调用 request.BetterGetResponse() 来解决

//-----------------------------------------------------------------------
//
//     Copyright (c) 2011 Garrett Serack. All rights reserved.
//
//
//     The software is licensed under the Apache 2.0 License (the "License")
//     You may not use the software except in compliance with the License.
//
//-----------------------------------------------------------------------

namespace CoApp.Toolkit.Extensions {
    using System;
    using System.Net;

    public static class WebRequestExtensions {
        public static WebResponse BetterEndGetResponse(this WebRequest request, IAsyncResult asyncResult) {
            try {
                return request.EndGetResponse(asyncResult);
            }
            catch (WebException wex) {
                if( wex.Response != null ) {
                    return wex.Response;
                }
                throw;
            }
        }

        public static WebResponse BetterGetResponse(this WebRequest request) {
            try {
                return request.GetResponse();
            }
            catch (WebException wex) {
                if( wex.Response != null ) {
                    return wex.Response;
                }
                throw;
            }
        }
    }
}

您可以在我关于此主题的博客文章 http://fearthecowboy.com/2011/09/02/fixing-webrequests-desire-to-throw-exceptions-instead-of-returning-status/ 中了解更多相关信息。