C＃的HttpClient PostAsync变成204到404 [英] C# HttpClient PostAsync turns 204 into 404

问题描述

考虑到这种服务的WebAPI：

  [ActionName（KillPerson）]
[HttpPost]
公共无效KillPerson（[FromBody]长ID）
{
    //杀死
}
 

这HttpClient的PostAsync电话：

  VAR的HttpClient =新的HttpClient {BaseAddress =新的URI（ClientConfiguration.ApiUrl）};
httpClient.DefaultRequestHeaders.Accept.Add（新MediaTypeWithQualityHeaderValue（应用/ JSON））;
VAR serializerSettings =新JsonSerializerSettings
{
    preserveReferencesHandling = preserveReferencesHandling.Objects，
    格式化= Formatting.Indented，
    ReferenceLoopHandling = ReferenceLoopHandling.Serialize
};
VAR serializedParameter = JsonConvert.SerializeObject（参数，serializerSettings）;
VAR httpContent =新的StringContent（serializedParameter，Encoding.UTF8，应用/ JSON）;
VAR响应=等待httpClient.PostAsync（的serviceUrl，httpContent）.ConfigureAwait（假）;
response.EnsureSuccessStatus code（）;
 

我希望response.EnsureSuccessStatus code（）;到succede但它抛出一个404来代替。
有趣的是，提琴手告诉配有该服务的WebAPI正在恢复204如预期，当我调试它KillPerson运行没有问题。

更新：
我已经确定，当客户端code是一个PCL或Silverlight 5项目中这只是发生。完全相同的code将使预期的204，如果我重复它在Windows窗体应用程序。如果我点了Windows窗体应用包含在PCL它给我的404客户端再次code。

UPDATE2：
这样就解决了这个问题（尽管它困扰我没有尽头，我应该需要做的话）：

  [ActionName（KillPerson）]
[HttpPost]
公众的Htt presponseMessage KillPerson（[FromBody]长ID）
{
    返回this.Request.CreateResponse（的HTTPStatus code.OK）;
}
 

这重新引入404（提琴手还在说204和非Silverlight客户端运行正常）

  [ActionName（KillPerson）]
[HttpPost]
公众的Htt presponseMessage KillPerson（[FromBody]长ID）
{
    返回this.Request.CreateResponse（的HTTPStatus code.NoContent）;
}
 

更新3（解决）：
终于想通了这一点。看来你使用任何浏览器或客户端HTTP在Silverlight处理的选择。当使用浏览器HTTP处理很多东西是不支持 - 包括各种应对codeS和头。
调用HttpClient的固定前加上几行：

  WebRequest.Register preFIX（HTTP：//，WebRequestCreator.ClientHttp）;
WebRequest.Register preFIX（https：//开头，WebRequestCreator.ClientHttp）;
 

解决方案

终于想通了这一点。看来你使用任何浏览器或客户端HTTP在Silverlight处理的选择。当使用浏览器HTTP处理很多东西是不支持 - 包括各种应对codeS和头。调用HttpClient的固定前加上几行：

  WebRequest.Register preFIX（HTTP：//，WebRequestCreator.ClientHttp）;
WebRequest.Register preFIX（https：//开头，WebRequestCreator.ClientHttp）;
 

Given this WebApi service:

[ActionName("KillPerson")]
[HttpPost]
public void KillPerson([FromBody] long id)
{
    // Kill
}

And this HttpClient PostAsync call:

var httpClient = new HttpClient { BaseAddress = new Uri(ClientConfiguration.ApiUrl) };
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var serializerSettings = new JsonSerializerSettings
{
    PreserveReferencesHandling = PreserveReferencesHandling.Objects,
    Formatting = Formatting.Indented,
    ReferenceLoopHandling = ReferenceLoopHandling.Serialize
};
var serializedParameter = JsonConvert.SerializeObject(parameter, serializerSettings);
var httpContent = new StringContent(serializedParameter, Encoding.UTF8, "application/json");
var response = await httpClient.PostAsync(serviceUrl, httpContent).ConfigureAwait(false);
response.EnsureSuccessStatusCode();

I would expect response.EnsureSuccessStatusCode(); to succede but it throws a 404 instead. The funny thing is that fiddler tells med that the webapi service is returning 204 as expected and when I debug it the KillPerson runs without issue.

Update: I Have determined that this only happens when the client code is within a PCL or Silverlight 5 project. The exact same code will give the expected 204 if I duplicate it in a Windows forms application. If i point the Windows Forms app to client code contained in a PCL it gives me the 404 Again.

Update2: This resolves the issue (though it bothers me no end that I should need to do it):

[ActionName("KillPerson")]
[HttpPost]
public HttpResponseMessage KillPerson([FromBody] long id)
{
    return this.Request.CreateResponse(HttpStatusCode.OK);
}

This reintroduces the 404 (fiddler still says 204 and non-silverlight client runs fine)

[ActionName("KillPerson")]
[HttpPost]
public HttpResponseMessage KillPerson([FromBody] long id)
{
    return this.Request.CreateResponse(HttpStatusCode.NoContent);
}

Update 3 (resolved): Finally figured this out. Seems you get a choice of using either browser or client HTTP handling in Silverlight. When using browser HTTP handling a lot of stuff is unsupported - including various response codes and headers. Adding these lines before calling HttpClient fixed it:

WebRequest.RegisterPrefix("http://", WebRequestCreator.ClientHttp);
WebRequest.RegisterPrefix("https://", WebRequestCreator.ClientHttp);

解决方案

Finally figured this out. Seems you get a choice of using either browser or client HTTP handling in Silverlight. When using browser HTTP handling a lot of stuff is unsupported - including various response codes and headers. Adding these lines before calling HttpClient fixed it:

WebRequest.RegisterPrefix("http://", WebRequestCreator.ClientHttp);
WebRequest.RegisterPrefix("https://", WebRequestCreator.ClientHttp);

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