C#计算输入和输出文件流的MD5

Question

我使用这个，经过轻微修改，可以从文件共享中复制大文件，如果下载中断，可以继续复制。它在BackgroupWorker中运行并报告进度。这很好，但我希望每次将文件数据块写入磁盘时，都能将当前的MD5哈希写入磁盘(当前的总数，而不是每个块一次(。如果发现了一个部分文件，我想从文件中读取MD5哈希，如果它与部分文件的哈希相同，请继续复制。当文件被完全复制后，文件中的MD5哈希应该是完全复制的文件的MD5散列。我想稍后使用它来确定源和目标中的文件是否相同。谢谢你的帮助！

这是我目前的复制方法：

public static bool CopyFile(List<CopyObjects> FileList, FSObjToCopy job, BackgroundWorker BW)
{
Stopwatch sw = new Stopwatch();
long RestartPosition = 0;
bool Retry = false;
int BYTES_TO_READ = (0x200000)
foreach (CopyObjects co in FileList)
{
FileInfo fi = co.file;
FileInfo fo = null;
if (fi.Directory.FullName.StartsWith($@"{Test_Updater_Core.ServerName}{Test_Updater_Core.ServerTemplateRoot}"))
{
if (File.Exists(fi.FullName.Replace($@"{Test_Updater_Core.ServerName}{Test_Updater_Core.ServerTemplateRoot}", $@"{ Test_Updater_Core.USBStore_Drive.driveInfo.Name.Replace("\", "")}{Test_Updater_Core.UsbTemplateRoot}")))
{
fi = new FileInfo(fi.FullName.Replace($@"{Test_Updater_Core.ServerName}{Test_Updater_Core.ServerTemplateRoot}", $@"{Test_Updater_Core.USBStore_Drive.driveInfo.Name.Replace("\", "")}{Test_Updater_Core.UsbTemplateRoot}"));
co.destination = co.destination.Replace($@"{Test_Updater_Core.USBStore_Drive.driveInfo.Name.Replace("\", "")}{Test_Updater_Core.UsbTemplateRoot}", $@"{Test_Updater_Core.LocalInstallDrive}{Test_Updater_Core.LocalTemplateRoot}");
fo = new FileInfo($"{fi.FullName.Replace($@"{Test_Updater_Core.USBStore_Drive.driveInfo.Name.Replace("\", "")}{Test_Updater_Core.UsbTemplateRoot}", $@"{Test_Updater_Core.LocalInstallDrive}{Test_Updater_Core.LocalTemplateRoot}")}{Test_Updater_Core.TempFileExtension}");
}
}

//If a clean cancellation was requested, we do it here, otherwise the BackgroundWorker will be killed
if (BW.CancellationPending)
{
job.Status = FSObjToCopy._Status.Complete;
return false;
}
//If a pause is requested, we loop here until resume or termination has been signaled
while (job.PauseBackgroundWorker == true)
{
Thread.Sleep(100);
if (BW.CancellationPending)
{
job.Status = FSObjToCopy._Status.Complete;
return false;
}
Application.DoEvents();
}
if (fo == null)
fo = new FileInfo($"{fi.FullName.Replace(job.Source, co.destination)}{Test_Updater_Core.TempFileExtension}");
if (fo.Exists)
{
Retry = true;
RestartPosition = fo.Length - BYTES_TO_READ;
}
else
{
RestartPosition = 0;
Retry = false;
}
if (RestartPosition <= 0)
{
Retry = false;
}
sw.Start();
try
{
// Read source files into file streams
FileStream source = new FileStream(fi.FullName, FileMode.Open, FileAccess.Read);
// Additional way to write to file stream
FileStream dest = new FileStream(fo.FullName, FileMode.OpenOrCreate, FileAccess.Write);
// Actual read file length
int destLength = 0;
// If the length of each read is less than the length of the source file, read in chunks
if (BYTES_TO_READ < source.Length)
{
byte[] buffer = new byte[BYTES_TO_READ];
long copied = 0;
if (Retry)
{
source.Seek(RestartPosition, SeekOrigin.Begin);
dest.Seek(RestartPosition, SeekOrigin.Begin);
Retry = false;
}
while (copied <= source.Length - BYTES_TO_READ)
{
destLength = source.Read(buffer, 0, BYTES_TO_READ);
source.Flush();
dest.Write(buffer, 0, BYTES_TO_READ);
dest.Flush();
// Current position of flow
dest.Position = source.Position;
copied += BYTES_TO_READ;
job.CopiedSoFar += BYTES_TO_READ;
if (sw.ElapsedMilliseconds > 250)
{
job.PercComplete = (int)(float)((float)job.CopiedSoFar / (float)job.TotalFileSize * 100);
sw.Restart();
sw.Start();
job.ProgressCell.Value = job.PercComplete;
BW.ReportProgress(job.PercComplete < 100 ? job.PercComplete : 99);
}
if (BW.CancellationPending)
{
job.Status = FSObjToCopy._Status.Complete;
return false;
}
while (job.PauseBackgroundWorker == true)
{
Thread.Sleep(100);
if (BW.CancellationPending)
{
job.Status = FSObjToCopy._Status.Complete;
return false;
}
Application.DoEvents();
}
}
int left = (int)(source.Length - copied);
destLength = source.Read(buffer, 0, left);
source.Flush();
dest.Write(buffer, 0, left);
dest.Flush();
job.CopiedSoFar += left;
}
else
{
// If the file length of each copy is longer than that of the source file, the actual file length is copied directly.
byte[] buffer = new byte[source.Length];
source.Read(buffer, 0, buffer.Length);
source.Flush();
dest.Write(buffer, 0, buffer.Length);
dest.Flush();
job.CopiedSoFar += source.Length;
job.PercComplete = (int)(float)((float)job.CopiedSoFar / (float)job.TotalFileSize * 100);
job.ProgressCell.Value = job.PercComplete;
BW.ReportProgress(job.PercComplete < 100 ? job.PercComplete : 99);
}
source.Close();
dest.Close();
fo.LastWriteTimeUtc = fi.LastWriteTimeUtc;
if (File.Exists(fo.FullName))
{
if (File.Exists(fo.FullName.Replace($"{Test_Updater_Core.TempFileExtension}", "")))
{
File.Delete(fo.FullName.Replace($"{Test_Updater_Core.TempFileExtension}", ""));
}
File.Move(fo.FullName, fo.FullName.Replace($"{Test_Updater_Core.TempFileExtension}", ""));
}
job.ProgressCell.Value = job.PercComplete;
BW.ReportProgress(job.PercComplete);
}
catch (Exception ex)
{
MessageBox.Show($"There was an error copying:{Environment.NewLine}{fi}{Environment.NewLine}to:" +
$"{Environment.NewLine}{fo}{Environment.NewLine}The error is: {Environment.NewLine}{ex.Message}",
"Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
job.Status = FSObjToCopy._Status.Error;
return false;
}
finally
{
sw.Stop();
}
}
return true;
}

Answer 1

我决定在服务器上创建校验和文件，每个文件中都包含一系列校验和。当我复制文件时，我将校验和添加到一个内部列表中，并将它们与服务器列表进行比较。如果在某个时刻，它们不匹配，我会回到它们相同的时刻，然后从那里开始。在复制作业结束时，我将内部列表中的校验和写入磁盘，其名称与服务器的名称相同。如果我想检查文件的完整性，我可以将服务器文件与本地文件进行比较，并验证校验和。