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TCP Connection keep disconnecting with Analyzer Mindray BS240

I'm working on a TCP communication program for the chemestry analyzer "Mindray BS240". The problem is that the analyzer keep disconnecting and reconnecting (every 30s). Here is my code, what did I miss ?
private void startTcpListner()
{
try
{
var port = settings.LisPort;
IPAddress localAddr = IPAddress.Parse(settings.LisIpAddress);
// TcpListener server = new TcpListener(port);
server = new TcpListener(localAddr, port);
// Start listening for client requests.
server.Start();
// Buffer for reading data
var bytes = new byte[256];
String data = null;
LogManager.GetCurrentClassLogger().Info("Waiting for a connection... ");
// Perform a blocking call to accept requests.
// You could also use server.AcceptSocket() here.
var client = server.AcceptTcpClient();
LogManager.GetCurrentClassLogger().Info("Connected !");
data = null;
// Get a stream object for reading and writing
stream = client.GetStream();
// Enter the listening loop.
while (true)
{
while (!stream.DataAvailable) ;
int i;
// Loop to receive all the data sent by the client.
while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
// Translate data bytes to a ASCII string.
var line = Encoding.UTF8.GetString(bytes, 0, i);
LogManager.GetCurrentClassLogger().Info("Received: {0}", line);
data += line;
if (line.Length > 3 &&
line[line.Length - 2] == Hl7Helper.FileSeparator &&
line[line.Length - 1] == Hl7Helper.CarriageReturn)
{
handleMessage(data);
data = null;
}
}
}
}
catch (SocketException e)
{
LogManager.GetCurrentClassLogger().Error("SocketException: {0}", e);
}
catch (Exception e)
{
LogManager.GetCurrentClassLogger().Error(e);
}
finally
{
// Stop listening for new clients.
server.Stop();
}
}
In the log file, I have :
Waiting for a connection...
Connected !

C# client socket multiple send and receive

I am using sockets for TCP-IP connection and I would like to establish simple system send-receive from the client side.
Socket sck;
sck = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint localEndpt = new IPEndPoint(IPAddress.Parse("123.123.123.1"), 12345);
try
{
sck.Connect(localEndpt);
}
catch
{
Console.Write("Unable to Connect");
}
while (true)
{
Console.WriteLine("Enter Text");
string sendtext = Console.ReadLine();
byte[] Data = Encoding.ASCII.GetBytes(sendtext);
sck.Send(Data);
Console.WriteLine("Data Sent!");
byte[] bytesReceived = new byte[sck.ReceiveBufferSize];
int bytes = 0;
String strReceived = "";
int dataAvailable = 0;
while (dataAvailable == 0 || dataAvailable != sck.Available)
{
dataAvailable = sck.Available;
Thread.Sleep(100); // if no new data after 100ms assume transmission finished
}
if (sck.Available > 0)
{
bytes = sck.Receive(bytesReceived, bytesReceived.Length, 0);
strReceived+=Encoding.ASCII.GetString(bytesReceived, 0, bytes);
}
Console.WriteLine("Received from server: " + strReceived);
}
Console.Read();
The problem is that first requests goes throught but the second does not, because socket is not available anymore (socket "Availabe" attribute value is 0). What am I doing wrong? What would be the easiest way to establish multiple send-recieve requests (in order)?

This code works fine for me
private List<Socket> _clients = new List<Socket>();
private Thread _dataReceiveThread;
private bool _isConnected;
private void DataReceive()
{
while (_isConnected)
{
List<Socket> clients = new List<Socket>(_clients);
foreach (Socket client in clients)
{
try
{
if (!client.Connected) continue;
string txt = "";
while (client.Available > 0)
{
byte[] bytes = new byte[client.ReceiveBufferSize];
int byteRec = client.Receive(bytes);
if (byteRec > 0)
txt += Encoding.UTF8.GetString(bytes, 0, byteRec);
}
if (!string.IsNullOrEmpty(txt))
/* TODO: access the text received with "txt" */
}
catch (Exception e)
{
Exception_Handler(e);
}
}
}
}
Just run this code to get started
_isConnected = true;
_dataReceiveThread = new Thread(DataReceive);
_dataReceiveThread.Start();
Update list box in Cross thread:
This code can be placed in the comment section.
myListBox1.Invoke((Action)(() => { myListBox1.Items.Add(txt) }));

Socket. Available does NOT indicate whether the socket is available, but incoming data is available for reading:
https://msdn.microsoft.com/en-us/library/ee425135.aspx
Your program quits because it checks for a reply (incoming data) immediately after sending a message out. Use a Thread.Sleep before checking for data.
Maybe the message has not even been sent, because Socket.Send just places it in the network interface card's output buffer. When the socket finally sends the message, it will upare the connection state. If it got no reply (on a TCP connection), it will tell you that it is disconnected when you query the state. On UDP it will tell you nothing, because UDP is connectionless.

C# Socket does not send complete data

I am trying to create a client/server application where a server sends commands to clients and clients send result back. The clients send data like this:
5|Hello
5 is the length of the string which is sent because then the server knows howmany characters it should receive before it should do something with that data. I tried to do that with this code:
private static void ReceiveCallback(IAsyncResult AR)
{
try
{
while (!Encoding.ASCII.GetString(_buffer).Contains("|"))
{
}
string[] a = Encoding.ASCII.GetString(_buffer).Split('|');
while (Encoding.ASCII.GetString(_buffer).Length < (Int32.Parse(a[0]) + a[0].Length + 1))
{
}
Socket socket = (Socket)AR.AsyncState;
int received = socket.EndReceive(AR);
byte[] dataBuf = new byte[received];
Array.Copy(_buffer, dataBuf, received);
string text = Encoding.ASCII.GetString(dataBuf);
if (!text.Contains("GET") && !text.Contains("HTTP") && text != null)
{
Console.WriteLine(DateTime.Now.ToString("h:mm:ss tt") + ":" + text);
}
socket.BeginReceive(_buffer, 0, _buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), socket);
}
catch
{
}
}
but this still does not give me the correct result. Also the CPU goes very high.
Picture of the result:
Can someone explain me why this happens? Thanks!

try to replace Encoding.ASCIIto Encoding.UTF8.
It can fix you issue.
Do note that you must to use the same encoding on both sides (sending and receiving data).
I hope it helps you.

have you tried using TcpClient? it can be way easier and gives you more control.
something like;
//make connection
NetworkStream stream = null;
socket = new TcpClient();
socket.Connect("192.168.12.12", 15879);
if (socket.Connected) {
stream = socket.GetStream();
}
//and than wait for tcp packets.
connectionThread = new Thread(ListenServer);
connectionThread.Start();
private void ListenToServer() {
Byte[] data = new Byte[1024];
String message = String.Empty;
Int32 dataLength = 0;
while (socket.Connected) {
try {
while (stream.DataAvailable) {
dataLength = stream.Read(data, 0, data.Length);
message = System.Text.Encoding.UTF8.GetString(data, 0, dataLength);
//do what ever you need here
Thread.Sleep(1);
}
} catch (Exception ex) {
}
Thread.Sleep(100);
}
moreover %1 cpu load!

Proxy server does not load images

I'm trying to make a proxy server with C#.
Here's my code:
static void Main(string[] args)
{
TcpListener server = null;
try
{
// Set the TcpListener on port 13000.
Int32 port = 13000;
IPAddress localAddr = IPAddress.Parse("127.0.0.1");
// TcpListener server = new TcpListener(port);
server = new TcpListener(localAddr, port);
// Start listening for client requests.
server.Start();
// Buffer for reading data
Byte[] bytes = new Byte[256];
String data = null;
WebRequest request;
WebResponse response;
// Enter the listening loop.
while (true)
{
Console.Write("Waiting for a connection... ");
// Perform a blocking call to accept requests.
// You could also user server.AcceptSocket() here.
TcpClient client = server.AcceptTcpClient();
Console.WriteLine("Connected!");
data = null;
// Get a stream object for reading and writing
NetworkStream stream = client.GetStream();
int i;
String[] input;
// Loop to receive all the data sent by the client.
while (stream.DataAvailable)
{
data = null;
i = stream.Read(bytes, 0, bytes.Length);
// Translate data bytes to a ASCII string.
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
Console.WriteLine(String.Format("Received: {0}", data));
input = data.Split();
Console.WriteLine("\n\r\n input[1]" + input[1] + "\n");
Stream dataStream;
StreamReader reader;
string responseFromServer;
try
{
request = WebRequest.Create(input[1]);
response = request.GetResponse();
// Process the data sent by the client.
data = data.ToUpper();
dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
reader = new StreamReader(dataStream);
// Read the content.
responseFromServer = reader.ReadToEnd();
// Display the content
Console.WriteLine(responseFromServer);
// Clean up the streams and the response.
byte[] msg = System.Text.Encoding.ASCII.GetBytes(responseFromServer);
// Send back a response.
stream.Write(msg, 0, msg.Length);
// Console.WriteLine("Sent: {0}", data);
//stream.Write();
reader.Close();
response.Close();
}
catch (System.UriFormatException e)
{
Console.WriteLine("Exception due to" + e.Data);
Console.WriteLine("Input[1] = " + input[1]);
}
data = null;
}
// Shutdown and end connection
client.Close();
}
}
catch (SocketException e)
{
Console.WriteLine("SocketException: {0}", e);
}
finally
{
// Stop listening for new clients.
server.Stop();
}
Console.WriteLine("\nHit enter to continue...");
Console.Read();
}
It does not work for ssl requests but seems to work for http.
However, it does not load any images.
I'm using Firefox as the browser.
Any ideas why?
Also is this the best way to make a proxy server? Are there any other methods?

After a bit of testing, I wrote my own code.
using System;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.IO;
using System.Threading;
using System.Text;
namespace SharpProxy
{
class MainClass
{
private static void StartAcceptingClient(IAsyncResult ar)
{
var tcpClient = server.EndAcceptTcpClient(ar);
server.BeginAcceptTcpClient(new AsyncCallback(StartAcceptingClient), null);
// Read the data stream from the client.
NetworkStream stream = tcpClient.GetStream();
byte[] buffer = new byte[256];
Console.WriteLine("====== GOT A NEW TCP CLIENT ====== " + tcpClient.Client.RemoteEndPoint.ToString());
int read = stream.Read(buffer, 0, 1);
MemoryStream saved = new MemoryStream();
saved.Write(buffer, 0, read);
bool isValid = false;
while (read > 0 )
{
read = stream.Read(buffer, 0, 1);
saved.Write(buffer, 0, read);
//Check if the last four bytes were a double \r\n.
var aBytes = saved.ToArray();
int len = aBytes.Length;
if (aBytes.Length >= 4 && aBytes[len - 1] == '\n' && aBytes[len - 2] == '\r' && aBytes[len - 3] == '\n' && aBytes[len - 4] == '\r')
{
isValid = true;
break;
}
}
Console.WriteLine("End of receive.");
string originalRequest = Encoding.ASCII.GetString(saved.ToArray());
byte[] origBytes = saved.ToArray();
saved.Close();
Console.WriteLine(originalRequest);
if (!isValid)
{
Console.WriteLine("This wasn't a valid request");
return;
}
//Find the hoster and do our own request.
string host = originalRequest.Split(new char[] { '\n' }).First(line => line.StartsWith("Host:"));
host = host.Substring(5).Trim(); //Cut of rest.
Console.WriteLine("The host is: " + host);
//Do our own request.
try
{
Socket sProxy = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
sProxy.Connect(host, 80);
sProxy.Send(origBytes);
//Now route everything between the tcpclient and this socket...
//create the state object
var state = new ProxyState() { ourSocket = sProxy, incomingClient = stream };
sProxy.BeginReceive(state.ReceiveBuffer, 0, state.ReceiveBuffer.Length, SocketFlags.None, new AsyncCallback(Receiver), state);
stream.BeginRead(state.SendBuffer, 0, state.SendBuffer.Length, new AsyncCallback(SendToHTTPServer), state);
}
catch (Exception) { Console.WriteLine("Exception while doing our own request"); }
}
static TcpListener server = null;
public static void Main(string[] args)
{
try
{
// Set the TcpListener on port 13000.
Int32 port = 13000;
IPAddress localAddr = IPAddress.Parse("0.0.0.0");
// TcpListener server = new TcpListener(port);
server = new TcpListener(localAddr, port);
// Start listening for client requests.
server.Start();
Console.WriteLine("Server started on " + server.LocalEndpoint.ToString());
server.BeginAcceptTcpClient(new AsyncCallback(StartAcceptingClient), null);
while (true)
Thread.Sleep(10);
}
catch (Exception) { Console.WriteLine("Setting up the server failed"); }
}
private static void SendToHTTPServer(IAsyncResult ar)
{
try
{
ProxyState back = (ProxyState)ar.AsyncState;
int rec = back.incomingClient.EndRead(ar);
//Push this content to the server
back.ourSocket.Send(back.SendBuffer.Take(rec).ToArray());
back.incomingClient.BeginRead(back.SendBuffer, 0, back.SendBuffer.Length, new AsyncCallback(SendToHTTPServer), back);
}
catch (Exception e) { Console.WriteLine("Exc. when sending to server: " + e.ToString()); }
}
static void Receiver(IAsyncResult state)
{
try
{
ProxyState back = (ProxyState)state.AsyncState;
int rec = back.ourSocket.EndReceive(state);
//Set up the back and forth connections
back.incomingClient.Write(back.ReceiveBuffer, 0, rec);
back.ourSocket.BeginReceive(back.ReceiveBuffer, 0, back.ReceiveBuffer.Length, SocketFlags.None, new AsyncCallback(Receiver), back);
}
catch (Exception e) { Console.WriteLine("Exc. when receiving from client: " + e.ToString()); }
}
//Every proxy connection has an end an and a beginning, plus a
//Sending buffer and a receive buffer
class ProxyState
{
public NetworkStream incomingClient { get; set; }
public Socket ourSocket { get; set; }
private byte[] buffReceive = new byte[512];
private byte[] buffSend = new byte[512];
public byte[] ReceiveBuffer { get { return buffReceive; } set { buffReceive = value; } }
public byte[] SendBuffer { get { return buffSend; } set { buffSend = value; } }
}
}
}
Here's how it works: I listen on a port, and wait for a HTTP request. This is ended by a double carriage return and a linefeed, a \r\n\r\n. As soon as that happens, I try to parse the original host from the request with a Linq statement. I open my own socket to the server, and make use of the asynchronous callbacks. Basically, you need to write everything that comes from the proxy-iniator to the HTTP-Server, and everything that the HTTP-Server sends back needs to be pushed back to the original client aswell. This is why I set up my own state-object, which just saves the incomming client and the Socket, which is connected to the original HTTP server. And as such, communication can happen and I act as a proxy server.
Here's a screenshot with all the connections done right:
This proxy server is far from perfect, but the basic concept should be clear. This gave me some inspiration.

You use a streamreader on binary image data, that is not going to work. Not every binary is a valid ASCII encoded string. You should read the response as binary, and write it to the other stream as binary as well. You can try to convert it to ascii to print it to the console, but do not use the converted text to respond, because all the non-valid ascii characters will be converted to ?-s. I did modify your code to first read the response in a MemoryStream, and write that back. The data written to the console is still converted, but not user anywhere else.
static void Main(string[] args)
{
TcpListener server = null;
try
{
// Set the TcpListener on port 13000.
Int32 port = 13000;
IPAddress localAddr = IPAddress.Parse("127.0.0.1");
// TcpListener server = new TcpListener(port);
server = new TcpListener(localAddr, port);
// Start listening for client requests.
server.Start();
// Buffer for reading data
Byte[] bytes = new Byte[256];
String data = null;
WebRequest request;
WebResponse response;
// Enter the listening loop.
while (true)
{
Console.Write("Waiting for a connection... ");
// Perform a blocking call to accept requests.
// You could also user server.AcceptSocket() here.
TcpClient client = server.AcceptTcpClient();
Console.WriteLine("Connected!");
data = null;
// Get a stream object for reading and writing
NetworkStream stream = client.GetStream();
int i;
String[] input;
// Loop to receive all the data sent by the client.
while (stream.DataAvailable)
{
data = null;
i = stream.Read(bytes, 0, bytes.Length);
// Translate data bytes to a ASCII string.
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
Console.WriteLine(String.Format("Received: {0}", data));
input = data.Split();
Console.WriteLine("\n\r\n input[1]" + input[1] + "\n");
Stream dataStream;
StreamReader reader;
string responseFromServer;
try
{
request = WebRequest.Create(input[1]);
response = request.GetResponse();
// Process the data sent by the client.
data = data.ToUpper();
dataStream = response.GetResponseStream();
MemoryStream ms = new MemoryStream();
dataStream.CopyTo(ms);
ms.Position = 0;
// Open the stream using a StreamReader for easy access.
reader = new StreamReader(ms);
// Read the content.
responseFromServer = reader.ReadToEnd();
// Display the content
Console.WriteLine(responseFromServer);
// Clean up the streams and the response.
byte[] msg = ms.ToArray();
// Send back a response.
stream.Write(msg, 0, msg.Length);
// Console.WriteLine("Sent: {0}", data);
//stream.Write();
reader.Close();
response.Close();
}
catch (System.UriFormatException e)
{
Console.WriteLine("Exception due to" + e.Data);
Console.WriteLine("Input[1] = " + input[1]);
}
data = null;
}
// Shutdown and end connection
client.Close();
}
}
catch (SocketException e)
{
Console.WriteLine("SocketException: {0}", e);
}
finally
{
// Stop listening for new clients.
server.Stop();
}
Console.WriteLine("\nHit enter to continue...");
Console.Read();
}

Send text string via TCP?

I just read and tested code of this great article in order to understand TCP Client and Server.
Now I need to do (I hope) really simple thing I need to send some string from TCP Client To TCP Server.
The string is serialized object and it is a XML in fact.
What I don't understand where I have to include this code in TCP Client and also in the TCP server.
TCP Client:
static void Main(string[] args)
{
while (true)
{
String server = "192.168.2.175"; // args[0]; // Server name or IP address
// Convert input String to bytes
byte[] byteBuffer = Encoding.ASCII.GetBytes("1024"); // Encoding.ASCII.GetBytes(args[1]);
// Use port argument if supplied, otherwise default to 8080
int servPort = 1311; // (args.Length == 3) ? Int32.Parse(args[2]) : 8080;//7 ;
TcpClient client = null;
NetworkStream netStream = null;
try
{
// Create socket that is connected to server on specified port
client = new TcpClient(server, servPort);
Console.WriteLine("Connected to server... sending echo string");
netStream = client.GetStream();
// Send the encoded string to the server
netStream.Write(byteBuffer, 0, byteBuffer.Length);
Console.WriteLine("Sent {0} bytes to server...", byteBuffer.Length);
int totalBytesRcvd = 0; // Total bytes received so far
int bytesRcvd = 0; // Bytes received in last read
// Receive the same string back from the server
while (totalBytesRcvd < byteBuffer.Length)
{
if ((bytesRcvd = netStream.Read(byteBuffer, totalBytesRcvd,
byteBuffer.Length - totalBytesRcvd)) == 0)
{
Console.WriteLine("Connection closed prematurely.");
break;
}
totalBytesRcvd += bytesRcvd;
}
Console.WriteLine("Received {0} bytes from server: {1}", totalBytesRcvd,
Encoding.ASCII.GetString(byteBuffer, 0, totalBytesRcvd));
}
catch (Exception ex)
{
// http://stackoverflow.com/questions/2972600/no-connection-could-be-made-because-the-target-machine-actively-refused-it
Console.WriteLine(ex.Message);
}
finally
{
if (netStream != null)
netStream.Close();
if (client != null)
client.Close();
}
Thread.Sleep(1000);
}
}
TCP Server
class Program
{
private const int BUFSIZE = 32; // Size of receive buffer
static void Main(string[] args)
{
int servPort = 1311; // (args.Length == 1) ? Int32.Parse(args[0]) : 8080;
TcpListener listener = null;
try
{
// Create a TCPListener to accept client connections
listener = new TcpListener(IPAddress.Any, servPort);
listener.Start();
}
catch (SocketException se)
{
// IPAddress.Any
Console.WriteLine(se.ErrorCode + ": " + se.Message);
//Console.ReadKey();
Environment.Exit(se.ErrorCode);
}
byte[] rcvBuffer = new byte[BUFSIZE]; // Receive buffer
int bytesRcvd; // Received byte count
for (; ; )
{ // Run forever, accepting and servicing connections
// Console.WriteLine(IPAddress.Any);
TcpClient client = null;
NetworkStream netStream = null;
//Console.WriteLine(IPAddress.None);
try
{
client = listener.AcceptTcpClient(); // Get client connection
netStream = client.GetStream();
Console.Write("Handling client - ");
// Receive until client closes connection, indicated by 0 return value
int totalBytesEchoed = 0;
while ((bytesRcvd = netStream.Read(rcvBuffer, 0, rcvBuffer.Length)) > 0)
{
netStream.Write(rcvBuffer, 0, bytesRcvd);
totalBytesEchoed += bytesRcvd;
}
Console.WriteLine("echoed {0} bytes.", totalBytesEchoed);
// Close the stream and socket. We are done with this client!
netStream.Close();
client.Close();
}
catch (Exception e)
{
Console.WriteLine(e.Message);
netStream.Close();
}
}
}
}

Converting my Comments into an answer:
I strongly suggest you use WCF, instead of implementing all the stuff yourself. In WCF, you create the interfaces (Service Contracts) and implementations (Services) and the framework abstracts all the communication / protocol details out.
You can use WCF Duplex to have two-way communications between server and client

The example that you give is a simple 'mirror', where the TCP server sends back to the client the data that it receives from it.
The data that you want to send is in the byteBuffer variable (you are currently sending the text "1024", I believe). So instead of initializing it with "1024", you could initialize it with the XML-serialized data that you want.
On the client side, conversely, instead of echoing the data back to the client, you could simply do whatever you need on the server side with the data, that is your XML object.