我在我的网站上设置了ASP.Net Web API,用于与
WPF桌面应用程序通信.我在API上有一个动作设置来从客户端应用程序接收二进制文件.但是在某些(看似随机的)情况下,当我从请求中获取所有字节时,不会读取所有字节.希望你可以让我知道如何以一种始终有效的方式做到这一点.这是代码：
客户端：
public static SubmitTurnResult SubmitTurn(int turnId,Stream fileStream)
{
HttpClient client = CreateHttpClient();
HttpContent content = new StreamContent(fileStream);
content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
content.Headers.ContentDisposition.FileName = "new-turn.Civ5Save";
content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
content.Headers.ContentLength = fileStream.Length;
HttpResponseMessage response = client.PostAsync(
string.Format("SubmitTurn?authKey={0}&turnId={1}",LocalSettings.Instance.AuthenticationKey,turnId
),content
).Result;
response.EnsureSuccessStatusCode();
return response.Content.ReadAsAsync<SubmitTurnResult>().Result;
}
SubmitTurnResult是一个枚举,用于定义服务器上的结果,turnId是此文件附加到的实体的ID,fileStream是读取磁盘字节的实际FileStream.
服务器端：
[HttpGet,HttpPost]
public SubmitTurnResult SubmitTurn(string authKey,int turnId)
{
try
{
bool worked = false;
int gameId = 0;
using (GmrEntities gmrDb = new GmrEntities())
{
var player = gmrDb.Users.FirstOrDefault(u => u.AuthKey == authKey);
if (player != null)
{
var turn = player.Turns.FirstOrDefault(t => t.TurnID == turnId);
if (turn != null)
{
byte[] saveFileBytes = null;
using (MemoryStream tempStream = new MemoryStream())
{
var task = this.Request.Content.CopyToAsync(tempStream);
task.Wait();
saveFileBytes = tempStream.ToArray();
tempStream.Close();
}
if (saveFileBytes.Length != this.Request.Content.Headers.ContentLength.Value)
{
throw new Exception(string.Format("Byte array length ({0}) not equal to HTTP content-length header ({1}). This is not good!",saveFileBytes.Length,this.Request.Content.Headers.ContentLength.Value));
}
worked = GameManager.SubmitTurn(turn,saveFileBytes,gmrDb);
if (worked)
{
gameId = turn.Game.GameID;
gmrDb.SaveChanges();
}
}
}
}
return SubmitTurnResult.OK;
}
catch (Exception exc)
{
DebugLogger.WriteExceptionWithComments(exc,string.Format("Diplomacy: Sumbitting turn for turnId: {0}",turnId));
return SubmitTurnResult.UnexpectedError;
}
}
解决方法
正如我之前的评论中所述,我们遇到了与StreamContent相同的行为,但是在从Windows Server 2003 Web API服务流式传输响应时.它不会在2008年重新生成.实际上,如果我使用少量RAM(712 MB)配置VM,它也会在Windows Server 2008上进行重新编译,但是如果使用4 GB RAM则不会重新编译.此外,我们发现这只有一个带有FileStream的repros.将FileStream转换为MemoryStream会绕过问题(当然是以内存为代价).我们发现当响应流提前终止时,它总是在4096字节的边界上,并且它达到大约3.5MB的上限.
public static SubmitTurnResult SubmitTurn(int turnId,Stream fileStream)
{
HttpClient client = CreateHttpClient();
var memoryStream = new MemoryStream((int)fileStream.Length);
fileStream.CopyTo(memoryStream);
fileStream.Close();
memoryStream.Seek(0,SeekOrigin.Begin);
HttpContent content = new StreamContent(memoryStream);
如果需要,只有在Stream是FileStream时才可以有条件地执行MemoryStream复制.
