远程服务器返回错误:(415)不支持的媒体类型

Question

我尝试将文本文件从WPF RESTful客户端上传到ASP .NET MVC WebAPI 2网站.

客户代码

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("http://localhost:22678/api/Account/UploadFile?fileName=test.txt&description=MyDesc1");

request.Method = WebRequestMethods.Http.Post;
request.Headers.Add("Authorization", "Bearer " + tokenModel.ExternalAccessToken);  
request.ContentType = "text/plain";
request.MediaType = "text/plain";
byte[] fileToSend = File.ReadAllBytes(@"E:\test.txt");  
request.ContentLength = fileToSend.Length;

using (Stream requestStream = request.GetRequestStream())
{
      // Send the file as body request. 
      requestStream.Write(fileToSend, 0, fileToSend.Length);
      requestStream.Close();
}

using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
                        Console.WriteLine("HTTP/{0} {1} {2}", response.ProtocolVersion, (int)response.StatusCode, response.StatusDescription);

WebAPI 2代码

[HttpPost]
[HostAuthentication(DefaultAuthenticationTypes.ExternalBearer)]
[Route("UploadFile")]
public void UploadFile(string fileName, string description, Stream fileContents)
{
    byte[] buffer = new byte[32768];
    MemoryStream ms = new MemoryStream();
    int bytesRead, totalBytesRead = 0;
    do
    {
        bytesRead = fileContents.Read(buffer, 0, buffer.Length);
        totalBytesRead += bytesRead;

        ms.Write(buffer, 0, bytesRead);
    } while (bytesRead > 0);

   var data = ms.ToArray() ;

    ms.Close();
    Debug.WriteLine("Uploaded file {0} with {1} bytes", fileName, totalBytesRead);
}

所以..在客户端代码下我面临着这个异常

远程服务器返回错误:(415)不支持的媒体类型.

任何线索我缺少什么？

Answer 1

您正在设置ContentType = "text/plain",此设置驱动格式化程序选择.请查看Media Formatters以获取更多详细信息.

提取物:

在Web API中,媒体类型确定Web API如何序列化和反序列化HTTP消息体.内置对XML,JSON和表单urlencoded数据的支持,您可以通过编写媒体格式化程序来支持其他媒体类型.

因此,没有内置的text/plain格式化程序,即:不支持的媒体类型.您可以将内容类型更改为某些支持,内置或实现自定义类型(如链接中所述)

Answer 2

关于Radim上面提到的内容的+1 ...根据您的操作,Web API模型绑定会注意到该参数fileContents是一个复杂类型,并且默认情况下假定使用格式化程序读取请求正文内容.(请注意,由于fileName和description参数属于 string类型,因此默认情况下它们应来自uri).

您可以执行以下操作以防止发生模型绑定:

[HttpPost]
[HostAuthentication(DefaultAuthenticationTypes.ExternalBearer)]
[Route("UploadFile")]
public async Task UploadFile(string fileName, string description)
{
   byte[] fileContents = await Request.Content.ReadAsByteArrayAsync();

   ....
}

顺便说一下,你打算用这个做fileContents什么？你想创建一个本地文件？如果是的话,有一个更好的方法来处理这个问题.

根据您的上次评论更新:

你可以做的一个简单的例子

[HttpPost]
[HostAuthentication(DefaultAuthenticationTypes.ExternalBearer)]
[Route("UploadFile")]
public async Task UploadFile(string fileName, string description)
{
    Stream requestStream = await Request.Content.ReadAsStreamAsync();

    //TODO: Following are some cases you might need to handle
    //1. if there is already a file with the same name in the folder
    //2. by default, request content is buffered and so if large files are uploaded
    //   then the request buffer policy needs to be changed to be non-buffered to imporve memory usage
    //3. if exception happens while copying contents to a file

    using(FileStream fileStream = File.Create(@"C:\UploadedFiles\" + fileName))
    {
        await requestStream.CopyToAsync(fileStream);
    }

    // you need not close the request stream as Web API would take care of it
}