We Keep Coding

Transformation an image file in tcp/ip

I convert image file into a byte array and packetize it to 14-byte packets and send it via SerialPortEventHandler. on the other hand, in reciever part I lost some packets and when I generate recieved byte array in a new image file, the rest of the image, after the lost packet, shifted incorrectly, I have replaced lost packets with zero. while this works with text file perfectly. This is my code in client and server side:
client
_file = ofile.ConvertFileToByte(txtFileName.Text);
for (int k = 0; k < Configuration.PacketNumberInFrame; k++)
{
((BackgroundWorker)sender).ReportProgress((j * Configuration.PacketNumberInFrame + i) * 100 / Configuration.FileCount);
if (i + _numberOfByte <= Configuration.FileCount)
_packet = _file.SubArray(i, _numberOfByte);
}
//send packet
...
Server
try
{
while (true)
{
size = port.BytesToRead;
if (size >= 18)
break;
}
byte[] packet = new byte[size];
var str2 = port.Read(packet, 0, size);
if (System.Text.Encoding.Default.GetString(packet).Contains(Configuration.EndKeyByte) && !endFlag)
EndRecieving();
else
Extract(packet);
}
catch
(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
public Extract(packet)
{
Recieve_Data.Add( packet);
}
public EndRecieving()
{
for(int i=0;i< arrayResult.AddRange(packetData);i++)
{
arrayResult.AddRange(packetData);
}
string filePath = Configuration.LogFilePath + "\\CreatedFile-" + "."filePrefix.ToLower();
var stream = new FileStream(filePath,
FileMode.Create,
FileAccess.ReadWrite);
FileData oFile = new FileData();
stream.Write(result, 0, result.Length);
stream.Close();
}

Sending Hex string to TCP Socket

I am connecting VideoJet Printer to my PC using TCP/IP, creating C# windows dekstop application to read and write TCP Socket. When I am semding below Hex String using hercules software [When HEX Checkbox tick] it is responding but when I am sending same hex string from my C# code it is not reponding
Please suggest me where I am doing wrong in my code
try
{
client = new TcpClient("192.168.2.1", Convert.ToInt32("3001"));
// Translate the passed message into ASCII and store it as a Byte array.
Byte[] data = HexString2Bytes(richTextBox3.Text);
stream = client.GetStream();
// Send the message to the connected TcpServer.
stream.Write(data, 0, data.Length);
Console.WriteLine("Sent: {0}",richTextBox3.Text);
// Receive the TcpServer.response.
data = new Byte[65000];
var readStream = new MemoryStream();
int readBytes = stream.Read(data, 0, data.Length);
while (readBytes > 0)
{
readStream.Write(data, 0, readBytes);
readBytes = stream.Read(data, 0, data.Length);
}
var responseData = Encoding.ASCII.GetString(readStream.ToArray());
}
catch (Exception ex)
{
string errormsg = ex.ToString();
}
private byte[] HexString2Bytes(string hexString)
{
//check for null
if (hexString == null) return null;
//get length
int len = hexString.Length;
if (len % 2 == 1) return null;
int len_half = len / 2;
//create a byte array
byte[] bs = new byte[len_half];
try
{
//convert the hexstring to bytes
for (int i = 0; i != len_half; i++)
{
bs[i] = (byte)Int32.Parse(hexString.Substring(i * 2, 2), System.Globalization.NumberStyles.HexNumber);
}
}
catch (Exception ex)
{
MessageBox.Show("Exception : " + ex.Message);
}
//return the byte array
return bs;
}
Command Hex String
A503CA002C000000E4411251C0000000B60000003C0050006100720061006D0073003E00200020003C0043006F006C002000690064003D00220044006500760069006300650073002F0050004800640073002F0031002F005000720069006E00740049006E0066006F0072006D006100740069006F006E002200200067006500740046006C006100670073003D002200320022002000670065007400440065007000740068003D0022002D003100220020002F003E003C002F0050006100720061006D0073003E000000

I actually don't know, why you have to make a While loop. when you received number of bytes from Server readBytes, so you could finish a code with Encoding like this:
string responseData = Encoding.ASCII.GetString(data,0,readbytes);
To get more information, you can find in this link https://learn.microsoft.com/en-us/dotnet/api/system.net.sockets.tcpclient?view=net-5.0

Sending and receiving files keeps hanging

my program should be able to send and receive files but for some reason whenever i click on the send (button1) and receive (button2) buttons, it keeps hanging. Not sure if its something wrong my my codes? Also, I feel like my codes are pretty long as compared to other examples i found online but I'm not sure how to rectify.
Client codes
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint remoteEP = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9000);
private void Form1_Load(object sender, EventArgs e)
{
try
{
socket.Connect(remoteEP);
textBox2.Text = "Connected to Server";
}
catch (Exception ex)
{
textBox2.Text = "Unable to connect to Server";
textBox2.Text = ex.Message;
}
}
public const string SEND = "[SEND]";
public const string RECEIVE = "[RECEIVE]";
public const string QUIT = "[QUIT]";
private void button1_Click(object sender, EventArgs e)
{
textBox1.Clear();
textBox2.Clear();
NetworkStream stream = new NetworkStream(socket);
StreamReader reader = new StreamReader(stream);
StreamWriter writer = new StreamWriter(stream);
try
{
writer.WriteLine(RECEIVE);
writer.Flush();
writer.WriteLine(textBox1.Text);
writer.Flush();
Bitmap bmp = new Bitmap(#"C:\Users\Y400\Desktop\Lectures\Year 3\WAD\Week 11" + textBox1.Text);
MemoryStream ms = new MemoryStream();
bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
byte[] bmpBytes = ms.GetBuffer();
bmp.Dispose();
ms.Close();
int sent;
sent = sendData(socket, bmpBytes);
textBox1.Text = "Transferring file complete\r\n";
textBox1.Text += bmpBytes.Length + " bytes sent to Server.";
}
catch (Exception ex)
{
textBox2.Text = ex.Message;
}
}
public static int sendData (Socket s, byte[] data)
{
int total = 0;
int size = data.Length;
int left = size;
int sent;
byte[] datasize = new byte[4];
datasize = BitConverter.GetBytes(size);
sent = s.Send(datasize);
while(total<size)
{
sent = s.Send(data, total, left, SocketFlags.None);
total += sent;
left -= sent;
}
return total;
}
private void button2_Click(object sender, EventArgs e)
{
textBox2.Clear();
textBox1.Clear();
byte[] data = new byte[1024];
string fileN = textBox2.Text.Trim();
NetworkStream ns = new NetworkStream(socket);
StreamReader reader = new StreamReader(ns);
StreamWriter writer = new StreamWriter(ns);
writer.WriteLine(SEND);
writer.Flush();
writer.WriteLine(fileN);
writer.Flush();
try
{
while (true)
{
data = receiveData(socket);
MemoryStream ms = new MemoryStream(data);
break;
}
textBox2.Text = ("Receiving file from server ...\r\n" + data.Length + " bytes copied");
}
catch (Exception ex)
{
textBox2.Text = ex.Message;
}
}
public static byte[] receiveData (Socket s)
{
int total = 0;
int recv;
byte[] datasize = new byte[4];
recv = s.Receive(datasize, 0, 4, 0);
int size = BitConverter.ToInt32(datasize, 0);
int dataleft = size;
byte[] data = new byte[size];
while (total < size)
{
recv = s.Receive(data, total, dataleft, 0);
if (recv == 0)
{
break;
}
total += recv;
dataleft -= recv;
}
return data;
}
private void button3_Click(object sender, EventArgs e)
{
textBox1.Clear();
textBox2.Clear();
textBox2.Text = "Connection closed";
socket.Shutdown(SocketShutdown.Both);
socket.Close();
}
Server codes
class Program
{
public const string SEND = "[SEND]";
public const string RECV = "[RECV]";
public const string QUIT = "[QUIT]";
static void Main(string[] args)
{
runServer();
}
static void runServer()
{
try
{
byte[] data = new byte[1024];
Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint localEP = new IPEndPoint(IPAddress.Any, 9000);
server.Bind(localEP);
server.Listen(10);
Console.WriteLine("Waiting for Client ...");
Socket client = server.Accept();
Console.WriteLine("Client connected");
NetworkStream stream = new NetworkStream(client);
StreamReader reader = new StreamReader(stream);
StreamWriter writer = new StreamWriter(stream);
try
{
while(true)
{
string request = reader.ReadLine();
string filename = reader.ReadLine();
if (request == QUIT)
{
Console.WriteLine("Client disconnected");
break;
}
else if (request == SEND)
{
getFileFromClient(filename, client);
}
else if (request == RECV)
{
receiveFileFromClient(filename, client);
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
public static void getFileFromClient(string filename, Socket client)
{
try
{
FileStream output = File.OpenWrite(filename);
Console.WriteLine(filename + " created");
int count = 0;
while(true)
{
byte[] data = new byte[1024];
int size = client.Receive(data);
output.Write(data, 0, size);
count += size;
if(size<1024)
{
break;
}
}
output.Close();
Console.WriteLine(count + " bytes read from client");
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
public static void receiveFileFromClient(string filename, Socket client)
{
int count = 0;
FileStream input = File.OpenRead(filename);
Console.WriteLine("Reading " + filename);
while(true)
{
byte[] data = new byte[1024];
int bytesRead = input.Read(data, 0, 1024);
client.Send(data, bytesRead, SocketFlags.None);
count += bytesRead;
if(bytesRead < 1024)
{
break;
}
}
Console.WriteLine("Transferring file completed\r\n" + count + " bytes sent to Client");
input.Close();
}
}

Generally speaking
...try to approach the problem differently.
You can't just copy paste stuff from the Internet and hope for the best. You need to understand what you're doing thoroughly.
Regarding your exact problem
Take a look at the button2_Click method.
It contains a while loop which apparently never finishes.
while (true)
{
data = receiveData(socket);
MemoryStream ms = new MemoryStream(data);
break;
}
It does finish because of the break command. But this is all very hard to read.
When you copy paste code around and then apply quick fixes you end up with a pile of code which is very hard to debug.
It took me about 10 minutes to notice the fact that the client defines it's "message verbs" like so:
public const string SEND = "[SEND]";
public const string RECEIVE = "[RECEIVE]";
public const string QUIT = "[QUIT]";
while the server defines them like so:
public const string SEND = "[SEND]";
public const string RECV = "[RECV]";
public const string QUIT = "[QUIT]";
This is maybe not the only problem, but it is sufficient to create a deadlock,
because the server never executes the positive branch of this if statement:
else if (request == RECV)
{
receiveFileFromClient(filename, client);
}
so the client believes it is about to receive something, which proves to be false.
Also make sure you send the "SEND" and "RECEIVE" message verbs when you should and not mix them up.
Good luck!
PS: I would suggest you take a look at more simpler to use techniques for sending and receiving data, such as:
WCF
ASP.NET Web Services
Web API

Ignoring any logic errors that may occur in your programs, the way you are handling things in your client whenever it is doing an action it is doing it on the GUI thread. This will make your application seem like it is locking but instead it is executing your logic on the GUI thread.
The same problem is occurring on the server. It accepts a connection, and then goes on to receive the file. It will not be able to receive any other connection until it finished receiving the file.
The server is not without problems either because it is never checking if it receives 0 bytes from the socket. Which means that the client closed its end of the connection. You are simply assuming that if you receive less than 1024 you are receiving your last part of the file. This is simply not true for TCP. You only know you received the last part if you receive 0 bytes. TCP is a byte streaming protocol you cannot assume you will be receiving blocks of 1024 bytes. It is likely that this will be in fact the case, but you should not code it like that. Check for reception of 0 bytes. On the client you did check for 0 bytes, I am puzzled why you did not do the same on the server. The problematic part is this :
byte[] data = new byte[1024];
int size = client.Receive(data);
output.Write(data, 0, size);
count += size;
if(size<1024) //you can only break if the size is 0
{
break;
}
There are probably more bugs. As the other answer also indicated some other issues.

tcpClient sends file to tcpServer not completely or "damaged"

I'm working on a little console "Send file to Server" program.
The client (tcpClient) reads a file from his folder and sends it to the server (tcpServer), and the server receives it and writes this file into his folder.
I still have 2 problems:
If the client sends a ~19MB .txt file (which is full of random chars but no blanks!) to the server, the server receives the file, writes a ~19MB .txt file in his folder, but the .txt file in the server folder contains only in the first few lines of the original file, and the large rest contains only blanks. The .txt file is on the server side not complete...
If the client sends a 9KB .png file, the server receives it, writes it to his folder. But if I try to open this .png file from the server folder, then I get an error message which says, that this file is too large or maybe damaged... (the .png file in the server folder has the right .png extension and the typical icon).
Server:
public void recieveFile() {
NetworkStream nws = clientconnection.GetStream();
StreamReader sr = new StreamReader(nws);
StreamWriter sw = new StreamWriter(nws);
// Recieve filename
string filename = sr.ReadLine().Remove(0, 10);
// Recieve filesize
long filesize = Convert.ToInt64(sr.ReadLine().Remove(0, 10));
Byte[] fileBytes = new Byte[filesize];
nws.Read(fileBytes, 0, fileBytes.Length);
nws.Close();
var a = File.OpenWrite(filename);
a.Write(fileBytes, 0, fileBytes.Length);
a.Flush();
a.Close();
}
Client:
public void sendFileToServer(String filename) {
var a = File.OpenRead(filename);
FileInfo fo = new FileInfo(filename);
long filesize = fo.Length;
// Write file into fileBytes-Array
Byte[] fileBytes = new Byte[filesize];
a.Read(fileBytes, 0, fileBytes.Length);
a.Close();
// Send filename to server
sw.WriteLine("Filename: " + filename);
sw.Flush();
// Send filesize to server
sw.WriteLine("Filesize: " + filesize);
sw.Flush();
// Send fileBytes to server
NetworkStream nws = clientConnection.GetStream();
nws.Write(fileBytes, 0, fileBytes.Length);
nws.Flush();
nws.Close();
sw.Close();
sr.Close();
clientConnection.Close();
}

My startpost-version is full of several mistakes. Here the now 100% working version:
Client:
public void sendFileToServer(String filename) {
var a = File.OpenRead(filename);
FileInfo fo = new FileInfo(filename);
long filesize = fo.Length;
// Send filename to server
sw.WriteLine("Filename: " + filename);
sw.Flush();
// Send filesize to server
sw.WriteLine("Filesize: " + filesize);
sw.Flush();
// Write file into fileBytes-Array and sends it in parts
Byte[] fileBytes = new Byte[1024];
long count = filesize;
while (count > 0) {
int recieved = a.Read(fileBytes, 0, fileBytes.Length);
a.Flush();
nws.Write(fileBytes, 0, recieved);
nws.Flush();
count -= recieved;
}
a.Close();
nws.Close();
sw.Close();
sr.Close();
clientConnection.Close();
}
Server:
public void recieveFile() {
NetworkStream nws = clientconnection.GetStream();
StreamReader sr = new StreamReader(nws);
StreamWriter sw = new StreamWriter(nws);
// Recieve filename
string filename = sr.ReadLine().Remove(0, 10);
// Recieve filesize
long filesize = Convert.ToInt64(sr.ReadLine().Remove(0, 10));
long count = filesize;
Byte[] fileBytes = new Byte[1024];
var a = File.OpenWrite(filename);
while (count > 0) {
int recieved = nws.Read(fileBytes, 0, fileBytes.Length);
nws.Flush();
a.Write(fileBytes, 0, recieved);
a.Flush();
count -= recieved;
}
nws.Close();
a.Close();
sr.Close();
sr.Close();
clientconnection.Close();
}

Transferring files through sockets (bir and small sized)

Hello I'm trying to implement a server and client couple that can transfer files of any kind and any size but there is a problem I somehow corrupt files. I tried lots of methods but can't figure it out. So basicly I can connect ,I can understand which file does client want, and can send it through sockets. When I try to open that file it shows me an error message(Tried winrar, mp4, avi files) Here is my code:
//Server
private void Receive(string receivedFileName, string fileSize)
{
try
{
int receivedBytesLen = 0;
byte[] incomingFile = new byte[int.Parse(fileSize)];
activity.AppendText("Preparing to download... \n");
while (incomingFile != null && int.Parse(fileSize) > receivedBytesLen)
{
tempSocket.Receive(incomingFile);
receivedBytesLen = incomingFile.Length;
int fileNameLen = BitConverter.ToInt32(incomingFile, 0);
File.WriteAllBytes(fileDir + "//" + receivedFileName, incomingFile);
}
activity.AppendText("File saved to " + fileDir + "\n");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
//////////////////////////////////////////////////////////////////////
//server option 2
private void Receive(string receivedFileName, string fileSize)
{
try
{
byte[] incomingFile = new byte[10124 * 5000];
activity.AppendText("Preparing to download... \n");
BinaryWriter bWrite = new BinaryWriter(File.Open(folderBrowserDialog1.SelectedPath + "//" + receivedFileName, FileMode.Append));
int receivedBytesLen = tempSocket.Receive(incomingFile, incomingFile.Length, 0);
int fileNameLen = BitConverter.ToInt32(incomingFile, 0);
//string fileName = Encoding.UTF8.GetString(incomingFile, 4, fileNameLen);
//bWrite.Write(incomingFile, 4 + fileNameLen, receivedBytesLen - 4 - fileNameLen);
while (receivedBytesLen > 0)
{
receivedBytesLen = tempSocket.Receive(incomingFile, incomingFile.Length, 0);
if (receivedBytesLen == 0)
{
bWrite.Close();
}
else
{
bWrite.Write(incomingFile, 0, receivedBytesLen);
}
}
activity.AppendText("File saved to " + fileDir + "\n");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
/////////////////////////////////////////////////////////////////////
//client
private void Upload_Click(object sender, EventArgs e)
{//Uploads selected file after clicking upload button.
try
{
if (clientSocket.Connected)
{
byte[] buffer = new byte[1024];
byte[] sendingFile = null;
sendingFile = File.ReadAllBytes(openFileDialog1.FileName);
FileInfo f = new FileInfo(openFileDialog1.FileName);
string fileSize = f.Length.ToString();
buffer = Encoding.Default.GetBytes(getUserName.Text + "Upload" + openFileDialog1.SafeFileName + "size" + fileSize + "end");
clientSocket.Send(buffer);
activityLog.AppendText("Sending File \n");
int bytesToBeSent = sendingFile.Length;
int bytesActuallySent = 0;
while(bytesActuallySent < bytesToBeSent){
bytesActuallySent += clientSocket.Send(sendingFile, bytesActuallySent, bytesToBeSent -bytesActuallySent, 0);
}
activityLog.AppendText("File Sent.\n");
}
}
catch(Exception ex){
MessageBox.Show(ex.Message);
}
}

server option #2 is better. But there are some improvements
socket receive buffer is limited decided by OS, generally is 8192
use FileStream in client and server and do not forget to close filestream after file download
client:
FileStream fileStream = new FileStream(filePath, FileMode.Open)
byte[] buff = new byte[8192];
do
{
bytesRead = fileStream.Read(buff, 0, buff.Length);
sock.send(dataSock, buff, bytesRead);
}while (bytesRead > 0);
fileStream.close();
server:
FileStream fileStream = new FileStream(filePath, FileMode.Open)
do
{
bytesRead = sock.receive(buff, 0, buff.Lenght);
fileStream.Write(buff, 0, bytesRead );
}while (bytesRead > 0);
fileStream.close();

In order to satisfy ANY sized file you need an option #3, one that reads a block of bytes til all bytes are received, your option #1 wouldn't do so well on a 3 GIG file running on 2 GIG box...
Here is a link: http://www.yoda.arachsys.com/csharp/readbinary.html
I like option #2 from this link.
However in the example they write to a memoryStream, you should write to a filestream, the target file.