C# FtpClient.OpenAppend方法代码示例

 public static void OpenAppend() {
     using (FtpClient conn = new FtpClient()) {
         conn.Host = "localhost";
         conn.Credentials = new NetworkCredential("ftptest", "ftptest");
         
         using (Stream ostream = conn.OpenAppend("/full/or/relative/path/to/file")) {
             try {
                 // be sure to seek your output stream to the appropriate location, i.e., istream.Position
                 // istream.Position is incremented accordingly to the writes you perform
                 // istream.Position == file size if the server supports getting the file size
                 // also note that file size for the same file can vary between ASCII and Binary
                 // modes and some servers won't even give a file size for ASCII files! It is
                 // recommended that you stick with Binary and worry about character encodings
                 // on your end of the connection.
             }
             finally {
                 ostream.Close();
             }
         }
     }
 }

        private void UploadBackupFile(FtpClient ftpClient, string ftpBackupPath, string backupFilePath)
        {
            Stream ftpBackupFile;
              long totalBytesWritten = 0;

              var backupFilename = Path.GetFileName(backupFilePath);

              var ftpBackupFilePath = ftpBackupPath + "/" + backupFilename;

              if (ftpClient.FileExists(ftpBackupFilePath))
              {
            var ftpBackupFileSize = ftpClient.GetFileSize(ftpBackupFilePath);

            totalBytesWritten = ftpBackupFileSize;

            ftpBackupFile = ftpClient.OpenAppend(ftpBackupPath + "/" + backupFilename, FtpDataType.Binary);
              }
              else
              {
            ftpBackupFile = ftpClient.OpenWrite(ftpBackupPath + "/" + backupFilename, FtpDataType.Binary);
              }

              try
              {
            using (var backupFile = File.OpenRead(backupFilePath))
            {
              int bytesRead;
              var totalBytes = backupFile.Length;
              var bytesWrittenLogPoint = 0.1;

              var buffer = new byte[4096];

              _log.Info(string.Format("Uploading {0} ({1:N0} bytes)...", backupFilename, totalBytes));

              if (totalBytesWritten > 0)
            backupFile.Seek(totalBytesWritten, SeekOrigin.Begin);

              while ((bytesRead = backupFile.Read(buffer, 0, buffer.Length)) > 0)
              {
            ftpBackupFile.Write(buffer, 0, bytesRead);

            totalBytesWritten += bytesRead;

            var writtenBytesPercentage = ((float)totalBytesWritten / totalBytes);

            if (writtenBytesPercentage >= bytesWrittenLogPoint)
            {
              _log.Info(
                string.Format(
                  "Backup file upload progress: {0:P} ({1:N0} bytes) of {2}.",
                  writtenBytesPercentage,
                  totalBytesWritten,
                  backupFilename));

              bytesWrittenLogPoint += 0.1;
            }
              }
            }
              }
              finally
              {
            ftpBackupFile.Dispose();
              }
        }