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C# Programming

Unable to write data to the transport connection: An established connection


Hello,

I'm trying to upload a file programatically and occasionally I get the
following error message.

Unable to write data to the transport connection: An established connection
was aborted by the software in your host machine.

Stack Trace
at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32
size)
   at System.Net.FtpDataStream.Write(Byte[] buffer, Int32 offset, Int32
size)
   at HSMoveFiles.FTPClient.Upload(FileInfo fi, String targetFilename) in
C:\DOTNET\HSMoveFiles\FTPClient.cs:line 177

The source code for FTPClient.cs came from the following URL
http://www.codeproject.com/vb/net/FtpClient.asp

The exception is been thrown when trying to write the Stream.
rs.Write(content, 0, dataRead)

Has anyone got any Idea why this might happen and how to solve it?

Exception is caught at line number 185. Throw ex;.

Here is the source code. See line number 177.

using System.Collections.Generic;

using System;

using System.Net;

using System.IO;

using System.Runtime.Remoting.Lifetime;

using System.Text.RegularExpressions;

namespace HSMoveFiles

{

#region "FTP client class"

/// <summary>

/// A wrapper class for .NET 2.0 FTP

/// </summary>

/// <remarks>

/// This class does not hold open an FTP connection but

/// instead is stateless: for each FTP request it

/// connects, performs the request and disconnects.

/// </remarks>

public class FTPClient

{

#region "CONSTRUCTORS"

/// <summary>

/// Blank constructor

/// </summary>

/// <remarks>Hostname, username and password must be set manually</remarks>

public FTPClient()

{

}

/// <summary>

/// Constructor just taking the hostname

/// </summary>

/// <param name="Hostname">in either ftp://ftp.host.com or ftp.host.com
form</param>

/// <remarks></remarks>

public FTPClient(string Hostname)

{

_hostname = Hostname;

}

/// <summary>

/// Constructor taking hostname, username and password

/// </summary>

/// <param name="Hostname">in either ftp://ftp.host.com or ftp.host.com
form</param>

/// <param name="Username">Leave blank to use 'anonymous' but set password
to your email</param>

/// <param name="Password"></param>

/// <remarks></remarks>

public FTPClient(string Hostname, string Username, string Password)

{

_hostname = Hostname;

_username = Username;

_password = Password;

}

#endregion

#region "Directory functions"

/// <summary>

/// Return a simple directory listing

/// </summary>

/// <param name="directory">Directory to list, e.g. /pub</param>

/// <returns>A list of filenames and directories as a List(of
String)</returns>

/// <remarks>For a detailed directory listing, use
ListDirectoryDetail</remarks>

public List<string> ListDirectory(string directory)

{

//return a simple list of filenames in directory

System.Net.FtpWebRequest ftp = GetRequest(GetDirectory(directory));

//Set request to do simple list

ftp.Method = System.Net.WebRequestMethods.Ftp.ListDirectory;

string str = GetStringResponse(ftp);

//replace CRLF to CR, remove last instance

str = str.Replace("\r\n", "\r").TrimEnd('\r');

//split the string into a list

List<string> result = new List<string>();

result.AddRange(str.Split('\r'));

return result;

}

/// <summary>

/// Return a detailed directory listing

/// </summary>

/// <param name="directory">Directory to list, e.g. /pub/etc</param>

/// <returns>An FTPDirectory object</returns>

public FTPdirectory ListDirectoryDetail(string directory)

{

System.Net.FtpWebRequest ftp = GetRequest(GetDirectory(directory));

//Set request to do simple list

ftp.Method = System.Net.WebRequestMethods.Ftp.ListDirectoryDetails;

string str = GetStringResponse(ftp);

//replace CRLF to CR, remove last instance

str = str.Replace("\r\n", "\r").TrimEnd('\r');

//split the string into a list

return new FTPdirectory(str, _lastDirectory);

}

#endregion

#region "Upload: File transfer TO ftp server"

/// <summary>

/// Copy a local file to the FTP server

/// </summary>

/// <param name="localFilename">Full path of the local file</param>

/// <param name="targetFilename">Target filename, if required</param>

/// <returns></returns>

/// <remarks>If the target filename is blank, the source filename is used

/// (assumes current directory). Otherwise use a filename to specify a name

/// or a full path and filename if required.</remarks>

public bool Upload(string localFilename, string targetFilename)

{

//1. check source

if (!File.Exists(localFilename))

{

throw (new ApplicationException("File " + localFilename + " not found"));

}

//copy to FI

FileInfo fi = new FileInfo(localFilename);

return Upload(fi, targetFilename);

}

/// <summary>

/// Upload a local file to the FTP server

/// </summary>

/// <param name="fi">Source file</param>

/// <param name="targetFilename">Target filename (optional)</param>

/// <returns></returns>

public bool Upload(FileInfo fi, string targetFilename)

{

//copy the file specified to target file: target file can be full path or
just filename (uses current dir)

//1. check target

string target;

if (targetFilename.Trim() == "")

{

//Blank target: use source filename & current dir

target = this.CurrentDirectory + fi.Name;

}

else if (targetFilename.Contains("/"))

{

//If contains / treat as a full path

target = AdjustDir(targetFilename);

}

else

{

//otherwise treat as filename only, use current directory

target = CurrentDirectory + targetFilename;

}

string URI = Hostname + target;

//perform copy

System.Net.FtpWebRequest ftp = GetRequest(URI);

//Set request to upload a file in binary

ftp.Method = System.Net.WebRequestMethods.Ftp.UploadFile;

ftp.UseBinary = true;

//Notify FTP of the expected size

ftp.ContentLength = fi.Length;

//create byte array to store: ensure at least 1 byte!

int BufferSize = 2048;

byte[] content = new byte[BufferSize - 1 + 1];

int dataRead;

//open file for reading

using (FileStream fs = fi.OpenRead())

{

try

{

//open request to send

using (Stream rs = ftp.GetRequestStream())

{

do

{

dataRead = fs.Read(content, 0, BufferSize);

rs.Write(content, 0, dataRead);

} while (!(dataRead < BufferSize));

rs.Close();

}
}

catch (Exception ex)

{

throw ex;

}

finally

{

//ensure file closed

fs.Close();

ftp = null;

}
}

return true;

}

#endregion

#region "Download: File transfer FROM ftp server"

/// <summary>

/// Copy a file from FTP server to local

/// </summary>

/// <param name="sourceFilename">Target filename, if required</param>

/// <param name="localFilename">Full path of the local file</param>

/// <returns></returns>

/// <remarks>Target can be blank (use same filename), or just a filename

/// (assumes current directory) or a full path and filename</remarks>

public bool Download(string sourceFilename, string localFilename, bool
PermitOverwrite)

{

//2. determine target file

FileInfo fi = new FileInfo(localFilename);

return this.Download(sourceFilename, fi, PermitOverwrite);

}

//Version taking an FtpFileInfo

public bool Download(FTPfileInfo file, string localFilename, bool
PermitOverwrite)

{

return this.Download(file.FullName, localFilename, PermitOverwrite);

}

//Another version taking FtpFileInfo and FileInfo

public bool Download(FTPfileInfo file, FileInfo localFI, bool
PermitOverwrite)

{

return this.Download(file.FullName, localFI, PermitOverwrite);

}

//Version taking string/FileInfo

public bool Download(string sourceFilename, FileInfo targetFI, bool
PermitOverwrite)

{

//1. check target

if (targetFI.Exists && !(PermitOverwrite))

{

throw (new ApplicationException("Target file already exists"));

}

//2. check source

string target;

if (sourceFilename.Trim() == "")

{

throw (new ApplicationException("File not specified"));

}

else if (sourceFilename.Contains("/"))

{

//treat as a full path

target = AdjustDir(sourceFilename);

}

else

{

//treat as filename only, use current directory

target = CurrentDirectory + sourceFilename;

}

string URI = Hostname + target;

//3. perform copy

System.Net.FtpWebRequest ftp = GetRequest(URI);

//Set request to download a file in binary mode

ftp.Method = System.Net.WebRequestMethods.Ftp.DownloadFile;

ftp.UseBinary = true;

//open request and get response stream

using (FtpWebResponse response = (FtpWebResponse)ftp.GetResponse())

{

using (Stream responseStream = response.GetResponseStream())

{

//loop to read & write to file

using (FileStream fs = targetFI.OpenWrite())

{

try

{

byte[] buffer = new byte[2048];

int read = 0;

do

{

read = responseStream.Read(buffer, 0, buffer.Length);

fs.Write(buffer, 0, read);

} while (!(read == 0));

responseStream.Close();

fs.Flush();

fs.Close();

}

catch (Exception)

{

//catch error and delete file only partially downloaded

fs.Close();

//delete target file as it's incomplete

targetFI.Delete();

throw;

}
}

responseStream.Close();

}

response.Close();

}

return true;

}

#endregion

#region "Other functions: Delete rename etc."

/// <summary>

/// Delete remote file

/// </summary>

/// <param name="filename">filename or full path</param>

/// <returns></returns>

/// <remarks></remarks>

public bool FtpDelete(string filename)

{

//Determine if file or full path

string URI = this.Hostname + GetFullPath(filename);

System.Net.FtpWebRequest ftp = GetRequest(URI);

//Set request to delete

ftp.Method = System.Net.WebRequestMethods.Ftp.DeleteFile;

try

{

//get response but ignore it

string str = GetStringResponse(ftp);

}

catch (Exception)

{

return false;

}

return true;

}

/// <summary>

/// Determine if file exists on remote FTP site

/// </summary>

/// <param name="filename">Filename (for current dir) or full path</param>

/// <returns></returns>

/// <remarks>Note this only works for files</remarks>

public bool FtpFileExists(string filename)

{

//Try to obtain filesize: if we get error msg containing "550"

//the file does not exist

try

{

long size = GetFileSize(filename);

return true;

}

catch (Exception ex)

{

//only handle expected not-found exception

if (ex is System.Net.WebException)

{

//file does not exist/no rights error = 550

if (ex.Message.Contains("550"))

{

//clear

return false;

}

else

{

throw;

}
}

else

{

throw;

}
}
}

/// <summary>

/// Determine size of remote file

/// </summary>

/// <param name="filename"></param>

/// <returns></returns>

/// <remarks>Throws an exception if file does not exist</remarks>

public long GetFileSize(string filename)

{

string path;

if (filename.Contains("/"))

{

path = AdjustDir(filename);

}

else

{

path = this.CurrentDirectory + filename;

}

string URI = this.Hostname + path;

System.Net.FtpWebRequest ftp = GetRequest(URI);

//Try to get info on file/dir?

ftp.Method = System.Net.WebRequestMethods.Ftp.GetFileSize;

string tmp = this.GetStringResponse(ftp);

return GetSize(ftp);

}

public bool FtpRename(string sourceFilename, string newName)

{

//Does file exist?

string source = GetFullPath(sourceFilename);

if (!FtpFileExists(source))

{

throw (new FileNotFoundException("File " + source + " not found"));

}

//build target name, ensure it does not exist

string target = GetFullPath(newName);

if (target == source)

{

throw (new ApplicationException("Source and target are the same"));

}

else if (FtpFileExists(target))

{

throw (new ApplicationException("Target file " + target + " already
exists"));

}

//perform rename

string URI = this.Hostname + source;

System.Net.FtpWebRequest ftp = GetRequest(URI);

//Set request to delete

ftp.Method = System.Net.WebRequestMethods.Ftp.Rename;

ftp.RenameTo = target;

try

{

//get response but ignore it

string str = GetStringResponse(ftp);

}

catch (Exception)

{

return false;

}

return true;

}

public bool FtpCreateDirectory(string dirpath)

{

//perform create

string URI = this.Hostname + AdjustDir(dirpath);

System.Net.FtpWebRequest ftp = GetRequest(URI);

//Set request to MkDir

ftp.Method = System.Net.WebRequestMethods.Ftp.MakeDirectory;

try

{

//get response but ignore it

string str = GetStringResponse(ftp);

}

catch (Exception)

{

return false;

}

return true;

}

public bool FtpDeleteDirectory(string dirpath)

{

//perform remove

string URI = this.Hostname + AdjustDir(dirpath);

System.Net.FtpWebRequest ftp = GetRequest(URI);

//Set request to RmDir

ftp.Method = System.Net.WebRequestMethods.Ftp.RemoveDirectory;

try

{

//get response but ignore it

string str = GetStringResponse(ftp);

}

catch (Exception)

{

return false;

}

return true;

}

#endregion

#region "private supporting fns"

//Get the basic FtpWebRequest object with the

//common settings and security

private FtpWebRequest GetRequest(string URI)

{

//create request

FtpWebRequest result = (FtpWebRequest)FtpWebRequest.Create(URI);

//Set the login details

result.Credentials = GetCredentials();

//Do not keep alive (stateless mode)

result.KeepAlive = true;

return result;

}

/// <summary>

/// Get the credentials from username/password

/// </summary>

private System.Net.ICredentials GetCredentials()

{

return new System.Net.NetworkCredential(Username, Password);

}

/// <summary>

/// returns a full path using CurrentDirectory for a relative file reference

/// </summary>

private string GetFullPath(string file)

{

if (file.Contains("/"))

{

return AdjustDir(file);

}

else

{

return this.CurrentDirectory + file;

}
}

/// <summary>

/// Amend an FTP path so that it always starts with /

/// </summary>

/// <param name="path">Path to adjust</param>

/// <returns></returns>

/// <remarks></remarks>

private string AdjustDir(string path)

{

return ((path.StartsWith("/")) ? "" : "/").ToString() + path;

}

private string GetDirectory(string directory)

{
string URI;

if (directory == "")

{

//build from current

URI = Hostname + this.CurrentDirectory;

_lastDirectory = this.CurrentDirectory;

}

else

{

if (!directory.StartsWith("/"))

{

throw (new ApplicationException("Directory should start with /"));

}

URI = this.Hostname + directory;

_lastDirectory = directory;

}

return URI;

}

//stores last retrieved/set directory

private string _lastDirectory = "";

/// <summary>

/// Obtains a response stream as a string

/// </summary>

/// <param name="ftp">current FTP request</param>

/// <returns>String containing response</returns>

/// <remarks>FTP servers typically return strings with CR and

/// not CRLF. Use respons.Replace(vbCR, vbCRLF) to convert

/// to an MSDOS string</remarks>

private string GetStringResponse(FtpWebRequest ftp)

{

//Get the result, streaming to a string

string result = "";

using (FtpWebResponse response = (FtpWebResponse)ftp.GetResponse())

{

long size = response.ContentLength;

using (Stream datastream = response.GetResponseStream())

{

using (StreamReader sr = new StreamReader(datastream))

{

result = sr.ReadToEnd();

sr.Close();

}

datastream.Close();

}

response.Close();

}

return result;

}

/// <summary>

/// Gets the size of an FTP request

/// </summary>

/// <param name="ftp"></param>

/// <returns></returns>

/// <remarks></remarks>

private long GetSize(FtpWebRequest ftp)

{

long size;

using (FtpWebResponse response = (FtpWebResponse)ftp.GetResponse())

{

size = response.ContentLength;

response.Close();

}

return size;

}

#endregion

#region "Properties"

private string _hostname;

/// <summary>

/// Hostname

/// </summary>

/// <value></value>

/// <remarks>Hostname can be in either the full URL format

/// ftp://ftp.myhost.com or just ftp.myhost.com

/// </remarks>

public string Hostname

{

get

{

if (_hostname.StartsWith("ftp://"))

{

return _hostname;

}

else

{

return "ftp://" + _hostname;

}
}

set

{

_hostname = value;

}
}

private string _username;

/// <summary>

/// Username property

/// </summary>

/// <value></value>

/// <remarks>Can be left blank, in which case 'anonymous' is
returned</remarks>

public string Username

{

get

{

return (_username == "" ? "anonymous" : _username);

}

set

{

_username = value;

}
}

private string _password;

public string Password

{

get

{

return _password;

}

set

{

_password = value;

}
}

/// <summary>

/// The CurrentDirectory value

/// </summary>

/// <remarks>Defaults to the root '/'</remarks>

private string _currentDirectory = "/";

public string CurrentDirectory

{

get

{

//return directory, ensure it ends with /

return _currentDirectory + ((_currentDirectory.EndsWith("/")) ? "" :
"/").ToString();

}

set

{

if (!value.StartsWith("/"))

{

throw (new ApplicationException("Directory should start with /"));

}

_currentDirectory = value;

}
}

#endregion

}

#endregion

#region "FTP file info class"

/// <summary>

/// Represents a file or directory entry from an FTP listing

/// </summary>

/// <remarks>

/// This class is used to parse the results from a detailed

/// directory list from FTP. It supports most formats of

/// </remarks>

public class FTPfileInfo

{

//Stores extended info about FTP file

#region "Properties"

public string FullName

{

get

{

return Path + Filename;

}
}

public string Filename

{

get

{

return _filename;

}
}

public string Path

{

get

{

return _path;

}
}

public DirectoryEntryTypes FileType

{

get

{

return _fileType;

}
}

public long Size

{

get

{

return _size;

}
}

public DateTime FileDateTime

{

get

{

return _fileDateTime;

}
}

public string Permission

{

get

{

return _permission;

}
}

public string Extension

{

get

{

int i = this.Filename.LastIndexOf(".");

if (i >= 0 && i < (this.Filename.Length - 1))

{

return this.Filename.Substring(i + 1);

}

else

{

return "";

}
}
}

public string NameOnly

{

get

{

int i = this.Filename.LastIndexOf(".");

if (i > 0)

{

return this.Filename.Substring(0, i);

}

else

{

return this.Filename;

}
}
}

private string _filename;

private string _path;

private DirectoryEntryTypes _fileType;

private long _size;

private DateTime _fileDateTime;

private string _permission;

#endregion

/// <summary>

/// Identifies entry as either File or Directory

/// </summary>

public enum DirectoryEntryTypes

{

File,

Directory

}

/// <summary>

/// Constructor taking a directory listing line and path

/// </summary>

/// <param name="line">The line returned from the detailed directory
list</param>

/// <param name="path">Path of the directory</param>

/// <remarks></remarks>

public FTPfileInfo(string line, string path)

{

//parse line

Match m = GetMatchingRegex(line);

if (m == null)

{

//failed

throw (new ApplicationException("Unable to parse line: " + line));

}

else

{

_filename = m.Groups["name"].Value;

_path = path;

Int64.TryParse(m.Groups["size"].Value, out _size);

//_size = System.Convert.ToInt32(m.Groups["size"].Value);

_permission = m.Groups["permission"].Value;

string _dir = m.Groups["dir"].Value;

if (_dir != "" && _dir != "-")

{

_fileType = DirectoryEntryTypes.Directory;

}

else

{

_fileType = DirectoryEntryTypes.File;

}

try

{

_fileDateTime = DateTime.Parse(m.Groups["timestamp"].Value);

}

catch (Exception)

{

_fileDateTime = Convert.ToDateTime(null);

}
}
}

private Match GetMatchingRegex(string line)

{

Regex rx;

Match m;

for (int i = 0; i <= _ParseFormats.Length - 1; i++)

{

rx = new Regex(_ParseFormats[i]);

m = rx.Match(line);

if (m.Success)

{

return m;

}
}

return null;

}

#region "Regular expressions for parsing LIST results"

/// <summary>

/// List of REGEX formats for different FTP server listing formats

/// </summary>

/// <remarks>

/// The first three are various UNIX/LINUX formats, fourth is for MS FTP

/// in detailed mode and the last for MS FTP in 'DOS' mode.

/// I wish VB.NET had support for Const arrays like C# but there you go

/// </remarks>

private static string[] _ParseFormats = new string[] {

"(?<dir>[\\-d])(?<permission>([\\-r][\\-w][\\-xs]){3})\\s+\\d+\\s+\\w+\\s+\ \w+\\s+(?<size>\\d+)\\s+(?<timestamp>\\w+\\s+\\d+\\s+\\d{4})\\s+(?<name>.+) ",

"(?<dir>[\\-d])(?<permission>([\\-r][\\-w][\\-xs]){3})\\s+\\d+\\s+\\d+\\s+( ?<size>\\d+)\\s+(?<timestamp>\\w+\\s+\\d+\\s+\\d{4})\\s+(?<name>.+)",

"(?<dir>[\\-d])(?<permission>([\\-r][\\-w][\\-xs]){3})\\s+\\d+\\s+\\d+\\s+( ?<size>\\d+)\\s+(?<timestamp>\\w+\\s+\\d+\\s+\\d{1,2}:\\d{2})\\s+(?<name>.+ )",

"(?<dir>[\\-d])(?<permission>([\\-r][\\-w][\\-xs]){3})\\s+\\d+\\s+\\w+\\s+\ \w+\\s+(?<size>\\d+)\\s+(?<timestamp>\\w+\\s+\\d+\\s+\\d{1,2}:\\d{2})\\s+(? <name>.+)",

"(?<dir>[\\-d])(?<permission>([\\-r][\\-w][\\-xs]){3})(\\s+)(?<size>(\\d+)) (\\s+)(?<ctbit>(\\w+\\s\\w+))(\\s+)(?<size2>(\\d+))\\s+(?<timestamp>\\w+\\s +\\d+\\s+\\d{2}:\\d{2})\\s+(?<name>.+)",

"(?<timestamp>\\d{2}\\-\\d{2}\\-\\d{2}\\s+\\d{2}:\\d{2}[Aa|Pp][mM])\\s+(?<d ir>\\<\\w+\\>){0,1}(?<size>\\d+){0,1}\\s+(?<name>.+)"
 };

#endregion

}

#endregion

#region "FTP Directory class"

/// <summary>

/// Stores a list of files and directories from an FTP result

/// </summary>

/// <remarks></remarks>

public class FTPdirectory : List<FTPfileInfo>

{

public FTPdirectory()

{

//creates a blank directory listing

}

/// <summary>

/// Constructor: create list from a (detailed) directory string

/// </summary>

/// <param name="dir">directory listing string</param>

/// <param name="path"></param>

/// <remarks></remarks>

public FTPdirectory(string dir, string path)

{

foreach (string line in dir.Replace("\n",
"").Split(System.Convert.ToChar('\r')))

{

//parse

if (line != "")

{

this.Add(new FTPfileInfo(line, path));

}
}
}

/// <summary>

/// Filter out only files from directory listing

/// </summary>

/// <param name="ext">optional file extension filter</param>

/// <returns>FTPdirectory listing</returns>

public FTPdirectory GetFiles(string ext)

{

return this.GetFileOrDir(FTPfileInfo.DirectoryEntryTypes.File, ext);

}

/// <summary>

/// Returns a list of only subdirectories

/// </summary>

/// <returns>FTPDirectory list</returns>

/// <remarks></remarks>

public FTPdirectory GetDirectories()

{

return this.GetFileOrDir(FTPfileInfo.DirectoryEntryTypes.Directory, "");

}

//internal: share use function for GetDirectories/Files

private FTPdirectory GetFileOrDir(FTPfileInfo.DirectoryEntryTypes type,
string ext)

{

FTPdirectory result = new FTPdirectory();

foreach (FTPfileInfo fi in this)

{

if (fi.FileType == type)

{

if (ext == "")

{

result.Add(fi);

}

else if (ext == fi.Extension)

{

result.Add(fi);

}
}
}

return result;

}

public bool FileExists(string filename)

{

foreach (FTPfileInfo ftpfile in this)

{

if (ftpfile.Filename == filename)

{

return true;

}
}

return false;

}

private const char slash = '/';

public static string GetParentDirectory(string dir)

{

string tmp = dir.TrimEnd(slash);

int i = tmp.LastIndexOf(slash);

if (i > 0)

{

return tmp.Substring(0, i - 1);

}

else

{

throw (new ApplicationException("No parent for root"));

}
}
}

#endregion

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