我有一些代码使用Task通过Web服务传输文件。但是，如果网络中断或发生超时，则会导致文件不完整。我真的想让这项服务尽可能可靠，但是我不确定在哪里真正开始添加代码会在没有发送一个块时陷阱，然后再尝试重新发送它多次但也没有发送下一个块直到完成。也许如果它不能重新发送该块超过X次，则完全失败并记录事件。
有人可以提出任何建议吗？
Action<Guid, string> action = (smGuid, pubAttFullPath) =>
{
try
{
//Set filename from object
string FileName;
FileName = System.IO.Path.GetFileName(pubAttFullPath.ToString());
//Declare Web Service
TransferFile.TransferFileSoapClient ws_TransferFile = new TransferFile.TransferFileSoapClient();
//
bool transfercompleted = false;
using (FileStream fs = new FileStream(
pubAttFullPath.ToString(),
FileMode.Open,
FileAccess.Read,
FileShare.Read))
{
//Declare Buffers and Counts
byte[] buffer = new byte[49152];
long fileSize = fs.Length;
long totalReadCount = 0;
int readCount;
float percentageComplete = 0;
//Loop and copy file until it changes to not exactly the same byte count as the buffer
//which means the file is about to complete.
while ((readCount = fs.Read(buffer, 0, buffer.Length)) > 0)
{
if (!transfercompleted)
{
totalReadCount += readCount;
byte[] bytesToTransfer;
if (readCount == buffer.Length)
{
//Copy bytes until buffer is different
bytesToTransfer = buffer;
ws_TransferFile.WriteBinaryFile("ABCD", bytesToTransfer, FileName);
percentageComplete = (totalReadCount / (float)fileSize * 100);
percentageComplete = (float)Math.Round(percentageComplete, 2, MidpointRounding.ToEven);
//Update progress to DB
InsertProgress.InsertProgressSoapClient ws_InsertProgress = new InsertProgress.InsertProgressSoapClient();
if (percentageComplete == 10.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 10.0);
}
if (percentageComplete == 20.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 20.0);
}
if (percentageComplete == 30.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 30.0);
}
if (percentageComplete == 40.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 40.0);
}
if (percentageComplete == 50.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 50.0);
}
if (percentageComplete == 60.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 60.0);
}
if (percentageComplete == 70.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 70.0);
}
if (percentageComplete == 80.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 80.0);
}
if (percentageComplete == 90.00)
{
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 90.0);
}
}
else
{
// Only a part is requred to upload,
// copy that part.
List<byte> b = new List<byte>(buffer);
bytesToTransfer = b.GetRange(0, readCount).ToArray();
ws_TransferFile.WriteBinaryFile("ABCD", bytesToTransfer, FileName);
percentageComplete = 100;
//Insert Progress as complete
InsertProgress.InsertProgressSoapClient ws_InsertProgress = new InsertProgress.InsertProgressSoapClient();
ws_InsertProgress.InsertProgressService(smGuid.ToString(), 100);
transfercompleted = true;
fs.Close();
break;
}
}
}
}
}
catch (Exception ex)
{
EventLog.WriteEntry("Application", ex.Message.ToString(), EventLogEntryType.Error);
}
答案 0 :(得分：0)
Web服务不适合文件传输。我使用了几次，但是传输的额外数据量使得传输数据的大小比使用简单处理程序发送文件大1.5-2倍。处理程序将允许您同样没有问题。通过适当的进度处理和恢复会导致很多问题。你真的应该重新考虑使用httphandler。如果你想使用webservice，这是一个很好的例子：
http://msdn.microsoft.com/en-us/library/ms172362%28v=vs.85%29.aspx
如果您决定使用 IHttpHandler ，请参阅：
http://msdn.microsoft.com/en-us/library/ms228090%28v=vs.100%29.aspx
然后您可以使用以下代码来正确处理重试/恢复：
using (Stream stream = new FileStream(
pubAttFullPath.ToString(),
FileMode.Open,
FileAccess.Read,
FileShare.Read))
{
context.Response.AddHeader("Accept-Ranges", "bytes");
context.Response.Buffer = false;
if (context.Request.Headers["Range"] != null)
{
context.Response.StatusCode = 206;
string[] range = context.Request.Headers["Range"].Split(new[] { '=', '-' });
startBytes = Convert.ToInt32(range[1]);
}
int dataToRead = size - startBytes;
context.Response.ContentType = "application/octet-stream";
context.Response.AddHeader("Content-Length", dataToRead.ToString());
context.Response.AddHeader("Connection", "Keep-Alive");
context.Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, Encoding.UTF8));
if (startBytes > 0)
{
context.Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, size - 1, size));
stream.Seek(startBytes, SeekOrigin.Begin);
}
while (dataToRead > 0)
{
// Verify that the client is connected.
if (context.Response.IsClientConnected)
{
// Read the data in buffer.
int length = stream.Read(buffer, 0, buffer.Length);
// Write the data to the current output stream.
context.Response.OutputStream.Write(buffer, 0, length);
// Flush the data to the HTML output.
context.Response.Flush();
dataToRead = dataToRead - length;
}
else
{
// prevent infinite loop if user disconnects
dataToRead = -1;
}
}
}