HttpClient，UseDefaultCredentials，Windows身份验证，.NET Core 2.0控制台应用程序接收401 Unauthorized

Question

我正在尝试从.NET Core 2.0控制台应用程序进行HTTP GET调用。端点需要Windows身份验证。

我的测试程序成功实现了net45框架目标。相比之下，netcoreapp2.0版本收到401 Unauthorized。

这是我的方法：

using System;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;

static async Task<string> Get(string serverUri, string requestUri)
{
    var handler = new HttpClientHandler() { UseDefaultCredentials = true };
    var client = new HttpClient(handler) { BaseAddress = new Uri(serverUri) };
    return await client.GetStringAsync(requestUri);
}

这是我的项目文件。

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFrameworks>net45;netcoreapp2.0</TargetFrameworks>
  </PropertyGroup>
  <ItemGroup Condition="'$(TargetFramework)' != 'netcoreapp2.0'">
    <PackageReference Include="System.Net.Http" Version="4.3" />
  </ItemGroup>
</Project>

运行.\bin\Debug\net45\HttpClientTest.exe会返回预期的JSON结果。

运行dotnet .\bin\Debug\netcoreapp2.0\HttpClientTest.dll收到401 Unauthorized。

Unhandled Exception: System.AggregateException: One or more errors occurred.
(Response status code does not indicate success: 401 (Unauthorized).) --->
 System.Net.Http.HttpRequestException: Response status code does not indicate success: 401 (Unauthorized).
   at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
   at System.Net.Http.HttpClient.<GetStringAsyncCore>d__27.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at HttpClientTest.Program.<Get>d__1.MoveNext() in C:\temp\HttpClientTest\Program.cs:line 24
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at HttpClientTest.Program.Main(String[] args) in C:\temp\HttpClientTest\Program.cs:line 16

我该如何解决？

我也尝试过以下变化，输出没有任何变化：

handler.Credentials = CredentialCache.DefaultNetworkCredentials;
handler.Credentials = CredentialCache.DefaultCredentials;
handler.Credentials = new NetworkCredential(username, password, domain);

Answer 1

所以我们遇到了与HttpClient相同的问题，但是在第一次请求它是未经授权的，但如果我们再做一个快速请求调用，它会很好地通过，我们获得授权。

如果我在.NET 4.7.1控制台应用程序上执行此操作，它将完美无缺。如果我在.NET 4.7.1空Web应用程序中执行它，它工作正常，只有我做.NET Core 2.x我们得到这个问题。

var result = string.Empty;
var responseMessage = _client.GetAsync(url).Result;

if (responseMessage.IsSuccessStatusCode)
{
    result = await responseMessage.Content.ReadAsStringAsync();
}
else
{
    var responseMessage2 = _client.GetAsync(url).Result;

    if (responseMessage2.IsSuccessStatusCode)
    {
        result = await responseMessage2.Content.ReadAsStringAsync();
    }
}

return result;