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异常

远程服务器返回错误：（415）不支持的媒体类型。

有什么线索我缺少什么？

Answer 1

您正在设置ContentType = "text/plain"，此设置会驱动格式化程序选择。请查看Media Formatters了解详情。

摘录：

在Web API中，媒体类型确定Web API序列化的方式反序列化HTTP消息体。有内置的XML支持， JSON和form-urlencoded数据，您可以支持其他媒体通过编写媒体格式化程序来填写类型。

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link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模型绑定会注意到参数fileContents是一个复杂类型，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来阻止模型绑定：

[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fileContents做什么？你想创建一个本地文件？如果是的话，有更好的方法来解决这个问题。

根据您的上次评论进行更新：

您可以做的快速示例

[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
}

远程服务器返回错误：（415）不支持的媒体类型

2 个答案: