使用 WebAPI 2 和 CORS 时出现 500 内部服务器错误答案

【问题标题】：Getting 500 Internal Server Error while using WebAPI 2 and CORS使用 WebAPI 2 和 CORS 时出现 500 内部服务器错误
【发布时间】：2015-01-05 06:09:20
【问题描述】：

我正在使用 Web-API 2 创建网络服务。我已经使用以下代码启用了跨域资源共享。

Web.config

    <?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=301879
  -->
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5" />
  </system.web>

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <connectionStrings>

  </connectionStrings>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
  </entityFramework>
<system.webServer>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
<customErrors mode="Off"/>
    </handlers>
<httpProtocol> <customHeaders> <add name="Access-Control-Allow-Origin" value="*" /> <add name="Access-Control-Allow-Methods" value="*" /> </customHeaders> </httpProtocol>
  </system.webServer></configuration>

API控制器：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using ProActiveWebServices.Models;
using System.Web.Hosting;
using System.IO;
using System.Drawing.Imaging;
using System.Net.Http.Headers;
using System.Drawing;
using System.Net.Mail;
using System.Text;

namespace ProActiveWebServices.Controllers
{

    public class EnquiryController : ApiController
    {
        ProActiveEntities db = new ProActiveEntities();
        List<Enquiry> en = new List<Enquiry> { };
        List<City> ct = new List<City> { };
        EnquiryList enquiryList = new EnquiryList();
        CityList cityList = new CityList();

        // GET api/<controller>
        [Route("api/GetAllEnquiry")]
        public HttpResponseMessage Get()
        {
            try
            {
                if (CheckAuthentication(Request) || 1==1)
                {
                    var enquiry = db.tbl_Enquiry.ToList();
                    foreach (var e in enquiry)
                    {
                        Enquiry _enquiry = new Enquiry();
                        _enquiry.FullName = e.FullName;
                        _enquiry.Id = e.EnquiryID;
                        _enquiry.CompanyName = e.CompanyName;
                        _enquiry.ContactAddress = e.ContactAddress;
                        _enquiry.Email = e.Email;
                        _enquiry.fk_CityID = e.fk_CityID;
                        _enquiry.Comment = e.Comment;
                        en.Add(_enquiry);
                    }
                    enquiryList.EnquiryLists = en;
                    HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.OK, new { Enquiry = enquiryList });
                    return response;
                }
                else
                {
                    HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.BadRequest, new { Error = "Invalid Header and Authorization" });
                    return response;
                }
            }
            catch (Exception ex)
            {
                HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.BadRequest, "Error:" + ex.ToString());
                return response;
            }

        }
    }
}

这是我的 WebAPIConfig.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.Headers;
using System.Web.Http;
using System.Web.Http.Cors;

namespace ProActiveWebServices
{
    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            // Web API configuration and services
            var cors = new EnableCorsAttribute("*", "*", "*");
            // Web API routes
            config.MapHttpAttributeRoutes();
            config.EnableCors(cors);
            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
            config.Formatters.JsonFormatter.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));
        }
    }
}

现在，当我在 localhost 上运行它时，一切正常。但是当在 godaddy 上托管 Web 服务时，我收到 500-Internal server 错误。我也在 web.config 中启用了 Access-Control-Allow-Origin。但还是没有成功

【问题讨论】：

您是针对 OPTIONS 请求获得 500（这意味着与 Web.Config 中的动词相关的内容）还是针对实际的 GET/POST 请求？禁用自定义错误应该让您看到完整的调用堆栈 - 使用 Fiddler 拦截和检查请求并发布调用堆栈。

标签： c# asp.net asp.net-web-api

【解决方案1】：

这是我在 GoDaddy 上运行服务所必需的。

将以下内容添加到您的 web.config 中（将这一行添加到您的 web.config 中存在一些缺点，请做一些研究，因为我记不清了，但是如果您用 google 搜索，会有大量关于它的信息）：

<system.webServer>
    <modules runAllManagedModulesForAllRequests="true" />
</system.webServer>

您可能还需要添加

<system.web>
    <securityPolicy>
         <trustLevel name="Full" policyFile="internal" />
     </securityPolicy>
     <trust level="Full" originUrl="" processRequestInApplicationTrust="true" />
</system.web>

【讨论】：

【解决方案2】：

如果您使用 web api 并在 web config 中通过 EnableCors 启用 Cors，我刚刚遇到此错误，那么您不需要在 web config 中再次编写它。

如果你的代码中没有任何未处理的异常，那么在你的 web api 配置中编写这个就可以了

public static void Register(HttpConfiguration config)
        {
            // Web API configuration and services

            // Web API routes

            var cors = new EnableCorsAttribute(
                origins: "*",
                headers: "*",
                methods: "*");
            config.EnableCors(cors);

            config.MapHttpAttributeRoutes();

            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
        }

【讨论】：