我使用这个解决方案：
public class UploadController : ApiController
{
private static ConcurrentDictionary<string, State> _state = new ConcurrentDictionary<string, State>();
public State Get(string id)
{
State state;
if (_state.TryGetValue(id, out state))
{
return state;
}
return null;
}
public async Task<HttpResponseMessage> Post([FromUri] string id)
{
if (Request.Content.IsMimeMultipartContent())
{
var state = new State(Request.Content.Headers.ContentLength);
if (!_state.TryAdd(id, state))
throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.Conflict));
var path = System.Web.Hosting.HostingEnvironment.MapPath("~/App_Data");
var provider = new FileMultipartStreamProvider(path, state.Start, state.AddBytes);
await Request.Content.ReadAsMultipartAsync(provider).ContinueWith(t =>
{
_state.TryRemove(id, out state);
if (t.IsFaulted || t.IsCanceled)
throw new HttpResponseException(HttpStatusCode.InternalServerError);
});
return Request.CreateResponse(HttpStatusCode.OK);
}
else
{
throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.NotAcceptable, "This request is not properly formatted"));
}
}
}
public class State
{
public long? Total { get; set; }
public long Received { get; set; }
public string Name { get; set; }
public State(long? total = null)
{
Total = total;
}
public void Start(string name)
{
Received = 0;
Name = name;
}
public void AddBytes(long size)
{
Received = size;
}
}
public class FileMultipartStreamProvider : MultipartStreamProvider
{
private string _rootPath;
private Action<string> _startUpload;
private Action<long> _uploadProgress;
public FileMultipartStreamProvider(string root_path, Action<string> start_upload, Action<long> upload_progress)
: base()
{
_rootPath = root_path;
_startUpload = start_upload;
_uploadProgress = upload_progress;
}
public override System.IO.Stream GetStream(HttpContent parent, System.Net.Http.Headers.HttpContentHeaders headers)
{
var name = (headers.ContentDisposition.Name ?? "undefined").Replace("\"", "").Replace("\\", "_").Replace("/", "_").Replace("..", "_");
_startUpload(name);
return new WriteFileStreamProxy(Path.Combine(_rootPath, name), _uploadProgress);
}
}
public class WriteFileStreamProxy : FileStream
{
private Action<long> _writeBytes;
public WriteFileStreamProxy(string file_path, Action<long> write_bytes)
: base(file_path, FileMode.Create, FileAccess.Write)
{
_writeBytes = write_bytes;
}
public override void EndWrite(IAsyncResult asyncResult)
{
base.EndWrite(asyncResult);
#if DEBUG
System.Threading.Thread.Sleep(100);
#endif
if (_writeBytes != null)
_writeBytes(base.Position);
}
public override void Write(byte[] array, int offset, int count)
{
base.Write(array, offset, count);
#if DEBUG
System.Threading.Thread.Sleep(100);
#endif
if (_writeBytes != null)
_writeBytes(base.Position);
}
}
以及非缓冲输入流的小配置：
config.Services.Replace(typeof(IHostBufferPolicySelector), new CustomPolicy());
实现了这个：
public class CustomPolicy : System.Web.Http.WebHost.WebHostBufferPolicySelector
{
public override bool UseBufferedInputStream(object hostContext)
{
return false;
}
}