one my application features is tod download files from our ftp server. And of course this feature reqiures to cancel this operation (Cancel Downloading).
Now, my Download Function is as follows:
try
{
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + uri + "/" + fileName));
reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
reqFTP.UseBinary = true;
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
reqFTP.UsePassive = true;
response = (FtpWebResponse)reqFTP.GetResponse();
ftpStream = response.GetResponseStream();
_isItOutputStream = true;
string dataLengthString = response.Headers["Content-Length"];
int dataLength = 0;
if (dataLengthString != null)
{
dataLength = Convert.ToInt32(dataLengthString);
}
long cl = response.ContentLength;
int bufferSize = 4048;
int readCount;
byte[] buffer = new byte[bufferSize];
readCount = ftpStream.Read(buffer, 0, bufferSize);
outputStream = new FileStream(filePath + "\\" + fileName, FileMode.Create);
bool first = true;
while (readCount > 0)
{
outputStream.Write(buffer, 0, readCount);
_actualDownloaded += readCount;
if (this.InvokeRequired)
{
ProgressBarDel _progressDel = new ProgressBarDel(ProgressBar);
this.Invoke(_progressDel, new object[] { _actualDownloaded, first });
}
first = false;
readCount = ftpStream.Read(buffer, 0, bufferSize);
}
ftpStream.Close();
outputStream.Close();
response.Close();
_isItOutputStream = false;
return true;
}
catch (Exception ee)
{
_downloadException = ee.Message;
if (ftpStream != null && outputStream!=null )
if (ftpStream.CanRead && outputStream.CanWrite)
{
ftpStream.Close();
outputStream.Close();
}
if (response != null)
response.Close();
return false;
}
Now as you can see in Catch Block you can see that i'm trying to interrupt this connection when the user clicks on Cancel button.
Canceling Operation Scenario:
1) Cancel button was clicked.
2) Call Function "DoSomeWorx()"
3) in "DoSomeWorx()" do:
if (_isItOutputStream)// where here i'm trying to check if it's downloading
{
ftpStream.Close();
outputStream.Close();
response.Close();
}
if (_startCopy)// check if copying to phone
{
IsCancelled();
}
_btnDownload2PhoneThread.Abort(); // actually this operation does what i did before but for some resoans it does this but it takes time...
_btnDownload2PhoneThread.Join();
The Problem is when I reach any of the following statments (ftpStream.Close();outputStream.Close();response.Close();)
it throws an exception "File unavailable(e.g file is busy)"
and this exception affects on re-downloading operation where it sees the file busy.
so how to avoid this exception?
I'm assuming that you have a form of some sort, so your performing the download on a thread.
What your probably better off doing is checking a "cancel" flag inside your while loop.
eg.
while(readcount > 0 && !cancel)
{
...
}
Then let your method gracefully cancel out.
Secondly you should use a using statement on your streams. That means that if you throw an exception, the finally block will guarantee that your stream gets disposed (which incidentally is why you would be receiving file busy, as the stream hasn't yet had it's destructor run, even though your method has completed)
Related
In my code I want to upload and download a specific JSON-File to a FTP-Server.
The serializing works great and also the upload. When i look up the file via - for example - FileZilla, the content of the file is correct. (on the server)
But when i download this file with my application (and with my code - NOT with FileZilla), I don't get any exceptions, but the file is nearly empty. This is the only content:
{}
And here is my code for downloading:
string ResponseDescription = "";
FtpWebRequest req = (FtpWebRequest)FtpWebRequest.Create("ftp://" + "ftp.strato.com" + "/" + verzeichnis + "/" + file.Name);
req.Method = WebRequestMethods.Ftp.DownloadFile;
req.Credentials = new NetworkCredential(this.benutzer, this.passwort);
req.UseBinary = true;
req.UsePassive = false;
req.Proxy = null;
try
{
FtpWebResponse response = (FtpWebResponse)req.GetResponse();
Stream stream = response.GetResponseStream();
byte[] buffer = new byte[2048];
FileStream fs = new FileStream(destinationFolder + #"/" + destinationFile.Name, FileMode.Create);
int ReadCount = stream.Read(buffer, 0, buffer.Length);
while (ReadCount > 0)
{
fs.Write(buffer, 0, ReadCount);
ReadCount = stream.Read(buffer, 0, buffer.Length);
}
ResponseDescription = response.StatusDescription;
fs.Close();
stream.Close();
return true;
}
catch (Exception e)
{
MessageBox.Show(e.Message); // TODO - better Errorhandling
return false;
}
I found the solution. It was my mistake. The problem wasnt the download - the code was correct (as you said).
After downloading the file the JSON-Deserialization runs and here was the cause. I had a little mistake in my deserialization-logic.
I have a bit of code that uses a Task to transfer a file over a web service. However if the network drops or a timeout occurs it results in an incomplete file. I'm really trying to make this service as reliable as possible, but I'm not really sure where to even really start to add code that will trap when a chunk was not sent, and then attempt to resend it multiple times but also not send the next chunk until that is done. And maybe if it cannot resend that chunk over X times, fail completely and log an event.
Can anyone suggest anything?
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);
}
Web service is bad idea for file transfer. I used it few times, but amount of additional data transfered is making size of transfered data 1,5-2 times bigger then sending file using simple handler. Handler will allow you to the same without issues. It causes al lot of problem with proper progress handling and resume. You realy should reconsider using httphandler. If you like to use webservice, here is good example:
http://msdn.microsoft.com/en-us/library/ms172362%28v=vs.85%29.aspx
If you decide to use IHttpHandler see:
http://msdn.microsoft.com/en-us/library/ms228090%28v=vs.100%29.aspx
And then you can use following piece of code to proper handle retry/resume:
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;
}
}
}
I'm trying to download a directory, using FTP in a C# application. I basically need to take a remote dir, and move it, and its contents into a local dir.
Here is the function I'm currently using, and what the log output and errors are. The sample I'm referencing is for getting files, and possibly not directories:
private void Download(string file, string destination)
{
try
{
string getDir = "ftp://" + ftpServerIP + ftpPath + file + "/";
string putDir = destination + "\\" + file;
Debug.WriteLine("GET: " + getDir);
Debug.WriteLine("PUT: " + putDir);
FtpWebRequest reqFTP;
reqFTP = (FtpWebRequest)FtpWebRequest.Create
(new Uri(getDir));
reqFTP.Credentials = new NetworkCredential(ftpUserID,
ftpPassword);
reqFTP.UseBinary = true;
reqFTP.KeepAlive = false;
reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
reqFTP.Proxy = null;
reqFTP.UsePassive = false;
FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
Stream responseStream = response.GetResponseStream();
FileStream writeStream = new FileStream(putDir, FileMode.Create);
int Length = 2048;
Byte[] buffer = new Byte[Length];
int bytesRead = responseStream.Read(buffer, 0, Length);
while (bytesRead > 0)
{
writeStream.Write(buffer, 0, bytesRead);
bytesRead = responseStream.Read(buffer, 0, Length);
}
writeStream.Close();
response.Close();
}
catch (WebException wEx)
{
MessageBox.Show(wEx.Message, "Download Error");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Download Error");
}
}
Debug:
GET: ftp://I.P.ADDR/SOME_DIR.com/members/forms/THE_FOLDER_TO_GET/
PUT: C:\Users\Public\Documents\iMacros\Macros\THE_FOLDER_TO_WRITE
A first chance exception of type 'System.Net.WebException' occurred in System.dll
MessageBox Output:
The requested URI is invalid for this FTP command.
The slash on the end of the getDir indicates a directory - can you use mget and pass a path like that ends in "/*"?
First time poster, long-time reader. I have a really annoying problem thats been getting on my nerves. Ive got a program set up so I listen for new files on an FTP server, if theres a new file I download it. From there I work on some of the information in the file, etc. My problem comes when I run through my sequence the second time. That is, on the first file I download everything is totally fine, but as soon as a new file gets detected and my program tries downloading it, my program just hangs.
private static void DownloadFile(string s)
{
try
{
FtpWebRequest request = (FtpWebRequest)WebRequest.Create("ftp://blabla.com/"+s);
request.Method = WebRequestMethods.Ftp.DownloadFile;
request.Credentials = new NetworkCredential("xxx" ,"zzz");
using (FtpWebResponse partResponse = (FtpWebResponse)request.GetResponse())
{
Stream partReader = partResponse.GetResponseStream();
byte[] buffer = new byte[1024];
FileInfo fi = new FileInfo(path);
FileStream memStream = fi.Create();
while (true)
{
int bytesRead = partReader.Read(buffer, 0, buffer.Length - 1);
if (bytesRead == 0)
break;
memStream.Write(buffer, 0, bytesRead);
}
partResponse.Close();
memStream.Close();
}
Console.WriteLine(DateTime.Now + " file downloaded");
MoveFileToInProgress(s);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
The line it hangs on is this one:
using (FtpWebResponse partResponse = (FtpWebResponse)request.GetResponse())
The reason my method here is static is because Im just running it in a different project to test it.. My question here is, how come it only ever dies on the second file? Ive been staring myself blind for hours now!
I ran into this problem as well... try finishing your request first and then closing it before trying to retrieve the response. That worked for me (actually tried it after reading comment by MartinNielsen). Here is what I did.
// connect to the ftp site
FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(ftpUri);
ftpRequest.Method = WebRequestMethods.Ftp.UploadFile;
ftpRequest.Credentials = new NetworkCredential(ftpUser, ftpPassword);
// setting proxy to null so that it does not go through the proxy
ftpRequest.Proxy = null;
// get file information
StreamReader fileStream = new StreamReader(filePath);
byte[] fileBytes = Encoding.UTF8.GetBytes(fileStream.ReadToEnd());
ftpRequest.ContentLength = fileBytes.Length;
fileStream.Close();
// open connection to ftp site
Stream ftpRequestStream = ftpRequest.GetRequestStream();
// write the file to the stream
ftpRequestStream.Write(fileBytes, 0, fileBytes.Length);
// close the stream
ftpRequestStream.Close();
// get the response from the server
FtpWebResponse ftpUploadResponse = (FtpWebResponse)ftpRequest.GetResponse();
string result = ftpUploadResponse.StatusDescription;
// close response
ftpUploadResponse.Close();
// return response to calling code
return result;
Here are a couple of the resources that I used when writing this code (won't let me post more than 2, there were more)
How to: Upload Files with FTP
Uploading a file -- "The requested URI is invalid for this FTP command"
I'm not expert on C# but I use this code to download files from my ftp:
public void Download(string filename)
{
// I try to download five times before crash
for (int i = 1; i < 5; i++)
{
try
{
FtpWebRequest ftp = (FtpWebRequest)FtpWebRequest.Create(Global.Path + "/" + filename);
ftp.Credentials = new NetworkCredential(User, Pass);
ftp.KeepAlive = false;
ftp.Method = WebRequestMethods.Ftp.DownloadFile;
ftp.UseBinary = true;
ftp.Proxy = null;
int buffLength = 2048;
byte[] buff = new byte[buffLength];
int contentLen;
string LocalDirectory = Application.StartupPath.ToString() + "/downloads/" + filename;
using (FileStream fs = new FileStream(LocalDirectory, FileMode.Create, FileAccess.Write, FileShare.None))
using (Stream strm = ftp.GetResponse().GetResponseStream())
{
contentLen = strm.Read(buff, 0, buffLength);
while (contentLen != 0)
{
fs.Write(buff, 0, contentLen);
contentLen = strm.Read(buff, 0, buffLength);
}
}
Process.Start(LocalDirectory);
break;
}
catch (Exception exc)
{
if (i == 5)
{
MessageBox.Show("Can't download, try number: " + i + "/5 \n\n Error: " + exc.Message,
"Problem downloading the file");
}
}
}
}
Tell me if it works for you :)
I'm saving an image from a web request and something really weird is happening. On roughly half of the 8,000 images I'm downloading I get IOEXCEPTION errors:
ERROR_ACCESS_DENIED (5)
INVALID_PARAMETER (87)
Before I save the file using file.open, I check to make sure the file does not exist. The exception is thrown at this line of code:
fileStream = File.Open(destination, FileMode.Create, FileAccess.Write, FileShare.None);
Below is the code:
public static bool DownloadFile(string url, string destination)
{
bool success = false;
System.Net.HttpWebRequest request = null;
System.Net.WebResponse response = null;
Stream responseStream = null;
FileStream fileStream = null;
try
{
request = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(url);
request.Method = "GET";
request.Timeout = 100000; // 100 seconds
request.Proxy = System.Net.GlobalProxySelection.GetEmptyWebProxy();
response = request.GetResponse();
responseStream = response.GetResponseStream();
fileStream = File.Open(destination, FileMode.Create, FileAccess.Write, FileShare.None);
//fileStream = File.Create(destination);
// read up to ten kilobytes at a time
int maxRead = 10240;
byte[] buffer = new byte[maxRead];
int bytesRead = 0;
int totalBytesRead = 0;
// loop until no data is returned
while ((bytesRead = responseStream.Read(buffer, 0, maxRead)) > 0)
{
totalBytesRead += bytesRead;
fileStream.Write(buffer, 0, bytesRead);
}
// we got to this point with no exception. Ok.
success = true;
}
catch (System.Net.WebException we)
{
// something went terribly wrong.
success = false;
//MessageBox.Show(exp.ToString());
writeErrFile(we.ToString(), url);
//Debug.WriteLine(exp);
}
catch (System.IO.IOException ie)
{
// something went terribly wrong.
success = false;
//MessageBox.Show(ie.InnerException.ToString());
writeErrFile(ie.ToString(), destination + " -- " + url);
//Debug.WriteLine(exp);
}
catch (Exception exp)
{
// something went terribly wrong.
success = false;
//MessageBox.Show(exp.ToString());
writeErrFile(exp.ToString(), destination + " -- " + url);
//Debug.WriteLine(exp);
}
finally
{
// cleanup all potentially open streams.
if (null != responseStream)
responseStream.Close();
if (null != response)
response.Close();
if (null != fileStream)
fileStream.Close();
}
// if part of the file was written and the transfer failed, delete the partial file
if (!success && File.Exists(destination))
File.Delete(destination);
return success;
}
I've been stuck on this for a couple of days. Any help would be appreciated in unimaginable orders of magnitude.
Use file.exists() to check if the file exists and file.create or file.openwrite to write the file.
From your code I can't see how you are checking the file exists.