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Can't get the text correctly over TCP

I know my title is not good but I did not know how to write this problem. I'm receiving a XML over tcp connection but the problem is the string is full of "\0" so I can't see the message when I use that string variable. I can do string.length and see It's filled but can't reach the text. I've tried replace method and it worked but I know this is not the correct solution. So here is my question how can I receive the text correctly?
TcpListener tcpListener = new TcpListener(Convert.ToInt16(_Port));
tcpListener.Start();
while (true)
{
Socket handlerSocket = tcpListener.AcceptSocket();
if (handlerSocket.Connected)
{
Control.CheckForIllegalCrossThreadCalls = false;
NetworkStream networkStream = new NetworkStream(handlerSocket);
byte[] myReadBuffer = new byte[102400000];
int numberOfBytesRead = 0;
string myCompleteMessage = "";
do
{
numberOfBytesRead = networkStream.Read(myReadBuffer, 0, myReadBuffer.Length);
myCompleteMessage += Encoding.UTF8.GetString(myReadBuffer,
}
while (networkStream.DataAvailable);
Console.WriteLine("Text: "+myCompleteMessage);
}
}
I've tried to change the Encoding.UTF8 to Encoding.ASCII and Encoding.UNICODE but it did not worked.
Update: My problem is still continue, the data I receive has "\0" before every character. I couldn't find why.. I use replace and inserting \0 again once I want to send data back. Can this be because of some sort of encoding? I've tried getEncodings aswell and tried many code pages but non work

It turns all the "\0"'s inside my string was because the data I receive was encoded with BigEndian.. when I used
myCompleteMessage += Encoding.BigEndianUnicode.GetString(myReadBuffer, 0, numberOfBytesRead);
everything worked well. Wanted to share this here in case if someone receive the same problem.

Using TcpClient on websocket receive data get \0\0\0\0

I have establish a connection with a websocket , i want to receive message from it. Following is my code for receiving message from the websocket.
//mClient is my TCP connection
byte[] bytes;
NetworkStream netStream;
string returndata;
while(true)
{
bytes = new byte[mClient.ReceiveBufferSize];
netStream = mClient.GetStream();
netStream.Read(bytes, 0, (int)mClient.ReceiveBufferSize);
returndata = Encoding.UTF8.GetString(bytes);
Console.WriteLine("This is what the host returned to you: " + returndata);
}
The data should be some json array when I open with browser , but i have receive weird data like
??\0\0\0\0\0\0\0\0\0\0\
And the second loop onwards is forever
\0\0\0\0\0\0\0\0\0\0\0
I have seen a Similar Question but i have no idea on his answer. May I know how to fix this thing and what is the problem ?

Just read the stream with a StreamReader instead of fiddling with array buffers and the encoding by yourself:
//mClient is my TCP connection
StringBuilder returndata = new StringBuilder();
Console.Write("This is what the host returned to you: ");
// the StreamReader handles the encoding for you
using(var sr = new StreamReader(mClient.GetStream(), Encoding.UTF8))
{
int value = sr.Read(); // read an int
while(value != -1) // -1 means, we're done
{
var ch = (char) value; // cast the int to a char
Console.Write(ch); // print it
returndata.Append(ch); // keep it
value = sr.Read(); // read next char
}
}
Console.WriteLine(" done.");
capture the result in a StringBuilder so you can convert that to a string if the loop ends (based on whatever condition that will be)

It won't work like that. WebSockets uses a framing protocol that you have to parse. Your JSON payload will be wrapped in one or multiple frames you need to read and parse.
https://www.rfc-editor.org/rfc/rfc6455#section-5.2

Trouble with sending using TCP File Transfer Client

I have to develop a simple TCP File Transfer Client as part of an exercise/demonstration but I am having trouble with data delivery.
I am already provided with the TCP File server which will receive the incoming files and I have to code a Client that will connect to and send a file to the server. Thus far I have been successful as far as converting the data of the selected file into to a format ready to transferring and successfully opening a connection and then sending of the data, however even encounter a problem on server that is receiving - I am not allowed to change the code of the server and should thus change my client code in such a way that the data sent can be interpreted by the server. Here is the code I use (some is left out which is simple overhead, like input-box to get IP address etc.):
Link for TCP Server VS Solution (if you prefer): https://www.mediafire.com/?682owf9wtdzmxac
TCP File Transfer Client Sending method:
private void TransferFile(string _sFileName, string _sIPAdress)
{
//Convert data for transfer
Stream strmfilestream = File.OpenRead(_sFileName);
Byte[] bFileBuffer = new Byte[strmfilestream.Length];
//Open TCP/IP Connection
TcpClient tcpClientSocket = new TcpClient(_sIPAdress,8080);
NetworkStream nsNetworkStream = tcpClientSocket.GetStream();
nsNetworkStream.Write(bFileBuffer,0,bFileBuffer.GetLength(0));
nsNetworkStream.Close();
}
*Note: _sFileName is just the full file path + File name from a OpenFileDialog.
Here is the Load Method of the server to get things going:
if (!Directory.Exists(#"C:\TCPFileServer"))
Directory.CreateDirectory(#"C:\TCPFileServer");
//Get Ip address of server host machine
IPHostEntry IPHost = Dns.GetHostEntry(Dns.GetHostName());
lblServerIP.Text = IPHost.AddressList[5].ToString();
lstSockets = new ArrayList();
Thread thdListener = new Thread(new ThreadStart(listenerThread));
thdListener.IsBackground = true; //This will enabe the thread to terminate when application is closed
thdListener.Start();
Here is the listener thread method:
public void listenerThread()
{
TcpListener tcpListener = new TcpListener(IPAddress.Any, 8080);
tcpListener.Start();
while (true)
{
Socket handlerSocket = tcpListener.AcceptSocket();
if (handlerSocket.Connected)
{
this.Invoke((Action)(() => lstConnections.Items.Add(handlerSocket.RemoteEndPoint.ToString() + " connected.")));
lock (this)
{
lstSockets.Add(handlerSocket);
}
ThreadStart thdsHandler = new ThreadStart(handlerThread);
Thread thdHandler = new Thread(thdsHandler);
thdHandler.Start();
}
}
}
And then lasty here is the handler thread method:
public void handlerThread()
{
try
{
int iBlockSize = 1024 * 3000; //3mb block size
Byte[] dataByte = new Byte[iBlockSize];
Byte[] rcvdData = new Byte[128000 * 1024];//128mb File Limit
Socket handlerSocket = (Socket)lstSockets[lstSockets.Count - 1];
NetworkStream networkStream = new NetworkStream(handlerSocket);
int i = 0;
int iRcvdBytes = 0;
while (true)
{
//Read from socket and store to buffer 'dataByte'
iRcvdBytes = networkStream.Read(dataByte, 0, iBlockSize);
dataByte.CopyTo(rcvdData, i);//Copy recieved bytes,from buffer, to another byte array
i += iRcvdBytes;
if (iRcvdBytes == 0) break;
}
//Get the File name length, BitConvertor occupies the first 4 bytes
int iFileNameLength = BitConverter.ToInt32(rcvdData, 0);
//Get the file name using length as the size and 4 as the offset
string sFileName = Encoding.ASCII.GetString(rcvdData, 4, iFileNameLength);
Stream fileStream = File.Open("C:\\TCPFileServer\\" + sFileName, FileMode.Create);
//Populate raw File on local machine
fileStream.Write(rcvdData, 4 + iFileNameLength, i - 4 - iFileNameLength);
fileStream.Close();
//Update BRS Net Files Server Log
this.Invoke((Action)(() => lstConnections.Items.Add(sFileName + ": Transfered.")));
//Close Connection
networkStream.Close();
handlerSocket = null; //Clear socket
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Now I have debugged and as far I can determine, the first time I can see a problem is when we are trying to determine the file name length where the code reads int iFileNameLength = BitConverter.ToInt32(rcvdData, 0); - When debugging this variable is always determined as '0', which I assume is not correct? I am not sure. The required results that needs to be achieved is that the Server should receive the file and after the successful transfer, the file name should be displayed in the ListBox.
Here is screen shots showing the problem i'm experiencing:
We can see that bytes are definitely received:
Note that the file name can not be retrieved from using the file name length and offset:
And thus, the following error occurs:
My experience and expertise lie elsewhere and this is the first time I am coding within this paradigm(File transfer over network). I do however have theoretical knowledge about/studied the OSI model and TCP/IP Protocol stack, but never coded anything like this. One note given to me was that the server was coded with the assumption that it will be executed on a specific PC and I am allowed to change code of the Server application if it is absolutely necessary.

Try this. You have to do thinks in reverse on the client and using a List makes things easier.
private void TransferFile(string _sFileName, string _sIPAdress)
{
List<Byte> bFileBuffer = File.ReadAllBytes(_sFileName).ToList();
byte[] bFileName = Encoding.ASCII.GetBytes(_sFileName);
bFileBuffer.InsertRange(0, bFileName);
//Get the File name length, BitConvertor occupies the first 4 bytes
byte[] brcvdDataCount = BitConverter.GetBytes((UInt32)_sFileName.Count());
bFileBuffer.InsertRange(0, brcvdDataCount);
//Open TCP/IP Connection
TcpClient tcpClientSocket = new TcpClient(_sIPAdress, 8080);
NetworkStream nsNetworkStream = tcpClientSocket.GetStream();
nsNetworkStream.Write(bFileBuffer.ToArray(), 0, bFileBuffer.Count);
nsNetworkStream.Close();
}​​

There are two things with the server code you should be aware of
/Get the File name length, BitConvertor occupies the first 4 bytes
int iFileNameLength = BitConverter.ToInt32(rcvdData, 0);
//Get the file name using length as the size and 4 as the offset
string sFileName = Encoding.ASCII.GetString(rcvdData, 4, iFileNameLength);​
1) You need to add a byte count to beginning of upload.
2) The code is using Ascii Encoding which means you can not upload binary data.

.NET C# to PHP via local TCP connection slow

I have a .NET C# console application acting as a client and a PHP script acting as a server. Both connect via localhost so there is no internet speed dependency. The problem I have is that when my client app sends a binary file, say only 100KB, it takes around over 30 seconds to complete. I expected this process to be just about instantaneous.
Here's some code:
.NET client app:
public bool SendToServer(string data)
{
data += "DONE"; // Terminator string
TcpClient tcp = new TcpClient(this.serverURL, this.serverPort);
NetworkStream stream = tcp.GetStream();
byte[] b = Encoding.ASCII.GetBytes(data);
int len = b.Length;
for (int i = 0; i < len; i++)
stream.Write(b, i, 1);
stream.Flush();
Console.WriteLine("Sent to server {0}", Convert.ToString(b) + " len: " + b.Length);
return true;
}
PHP server script:
class ImageService
{
public $ip, $port, $soc;
function Listen($ip, $port)
{
$this->ip = $ip;
$this->port = $port;
$this->soc = stream_socket_server("tcp://".$this->ip.":".$this->port, $errno, $errstr);
if(!$this->soc) Out($errno);
else
{
Out("created socket");
$buf = "";
while($con = stream_socket_accept($this->soc))
{
Out("accepted socket");
do{
$buf .= fread($con, 1);
if(strlen($buf) == 0) break 2;
}
while(substr($buf, -4) != "DONE");
$buf = substr($buf, 0, strlen($buf) - 4);
switch($buf)
{
case "quit":
break 2;
}
print '<img alt="image" src="data:image/jpeg;base64,'.$buf.'">';
$buf = "";
}
fclose($con);
fclose($this->soc);
Out("Closed connection");
}
}
}
Calls:
set_time_limit(0);
//error_reporting(E_ALL);
$is = new ImageService();
$is->Listen("127.0.0.1", 1234);

Having looked at your PHP code, I suspect this is actually the cause of the speed problem:
do{
$buf .= fread($con, 1);
if(strlen($buf) == 0) break 2;
}
while(substr($buf, -4) != "DONE");
Assuming that PHP works the same way as Java and .NET (i.e. assuming that .= creates a new string containing a copy of the previous data), you're creating a new string for every single byte... that's an O(n^2) operation, which is going to get nasty really quickly.
Additionally:
Your protocol is broken if you have "DONE" in the original data
Your protocol specifically deals with text, not binary data. It's possible that you're base64-encoding the binary data first (given the PHP) but that's inefficient too. If you've really got binary data, it's a good idea to transfer it as binary data. Sockets are entirely capable of doing that - there's no reason to get text involved at all unless your problem domain specifically requires text.
I suggest you write the length of the data to the socket first, as a 4 or 8 byte integer (depending on whether or not you think you'll ever need to transfer more than 4GB). Then you can read the length first in your PHP code, allocate an appropriately-sized buffer, and then keep reading from the socket into that buffer (reading a large chunk at a time) until you're done. That will be much more efficient and won't have the protocol issues mentioned above.

Mind boggling problem regarding RCON Protocol implementation in C#

I once again need your help figuring out this problem of mine...Been already a day and I can't seem to find out why this is happening in my code and output.
Ok.....so basically I am trying to implement the RCON Protocol of Valve in C#, so far I am getting the expected output given the code and sample usage below:
Usage:
RconExec(socket, "cvarlist");
Code:
private string RconExec(Socket sock, string command)
{
if (!sock.Connected) throw new Exception("Not connected");
//sock.DontFragment = true;
sock.ReceiveTimeout = 10000;
sock.SendTimeout = 10000;
//sock.Blocking = true;
Debug.WriteLine("Executing RCON Command: " + command);
byte[] rconCmdPacket = GetRconCmdPacket(command);
sock.Send(rconCmdPacket); //Send the request packet
sock.Send(GetRconCmdPacket("echo END")); //This is the last response to be received from the server to indicate the end of receiving process
RconPacket rconCmdResponsePacket = null;
string data = null;
StringBuilder cmdResponse = new StringBuilder();
RconPacket packet = null;
int totalBytesRead = 0;
do
{
byte[] buffer = new byte[4]; //Allocate buffer for the packet size field
int bytesReceived = sock.Receive(buffer); //Read the first 4 bytes to determine the packet size
int packetSize = BitConverter.ToInt32(buffer, 0); //Get the packet size
//Now proceed with the rest of the data
byte[] responseBuffer = new byte[packetSize];
//Receive more data from server
int bytesRead = sock.Receive(responseBuffer);
//Parse the packet by wrapping under RconPacket class
packet = new RconPacket(responseBuffer);
totalBytesRead += packet.String1.Length;
string response = packet.String1;
cmdResponse.Append(packet.String1);
Debug.WriteLine(response);
Thread.Sleep(50);
} while (!packet.String1.Substring(0,3).Equals("END"));
Debug.WriteLine("DONE..Exited the Loop");
Debug.WriteLine("Bytes Read: " + totalBytesRead + ", Buffer Length: " + cmdResponse.Length);
sock.Disconnect(true);
return "";
}
The Problem:
This is not yet the final code as I am just testing the output in the Debug window. There are a couple of issues occuring if I modify the code to it's actual state.
Removing Thread.Sleep(50)
If I remove Thread.Sleep(50), the output doesn't complete and ends up throwing an exception. I noticed the 'END' termination string is sent by the server pre-maturely. This string was expected to be sent by the server only when the whole list completes.
I tested this numerous times and same thing happens, if I don't remove the line, the list completes and function exits the loop properly.
Removing Debug.WriteLine(response); within the loop and outputting the string using Debug.WriteLine(cmdResponse.ToString()); outside the loop, only partial list data is displayed. If I compare the actual bytes read from the loop with the length of the StringBuilder instance, they're just the same? Click here for the output generated.
Why is this happening given the two scenarios mentioned above?

You are not considering that Socket.Receive very well could read fewer bytes than the length of the supplied buffer. The return value tells you the number of bytes that was actually read. I see that you are properly storing this value in a variable, but I cannot see any code that use it.
You should be prepared to make several calls to Receive to retrieve the entire package. In particular when you receive the package data.
I'm not sure that this is the reason for your problem. But it could be, since a short delay on the client side could be enough to fill the network buffers so that the entire package is read in a single call.
Try using the following code to retrieve package data:
int bufferPos = 0;
while (bufferPos < responseBuffer.Length)
{
bufferPos += socket.Receive(responseBuffer, bufferPos, responseBuffer.Length - bufferPos, SocketFlags.None);
}
Note: You should also support the case when the first call to Receive (the one where you receive the package's data length) doesn't return 4 bytes.