I'm writing a tcp server in c# and corresponding client in java. I'm testing the connection on localhost, and the client is able to connect to the server. However, when I'm sending messages, the client never receives them. Using the debugger I've verified that stream.Write(...) is executed. Any idea what the problem could be?
This is the c# server:
TcpClient client = (TcpClient)cl;
NetworkStream stream = client.GetStream();
byte[] msg = new byte[512];
int bytesRead;
while (running)
{
while (messages.getCount() > 0)
{
String msg = messages.Take();
if (cmd != null)
{
byte[] bytes = Encoding.UTF8.GetBytes(msg.ToCharArray());
try
{
stream.Write(bytes, 0, bytes.Length);
stream.Flush();
}
catch (Exception e)
{
}
}
}
Thread.Sleep(1000);
}
And the Java client:
public void run()
{
try
{
socket = new Socket(address, port);
in = new BufferedReader( new InputStreamReader( socket.getInputStream() ));
out = new PrintWriter(socket.getOutputStream());
running = true;
}
catch (Exception e){
e.printStackTrace();
running = false;
}
String data;
while(running)
{
try
{
data = in.readLine();
if(data != null)
{
processData(data);
}
}
catch (IOException e)
{
e.printStackTrace();
running = false;
break;
}
}
try
{
socket.close();
socket = null;
}
catch (IOException e)
{
e.printStackTrace();
}
running = false;
}
You're using BufferedReader.readLine(). Are your message strings terminated by a CR, LF, or CR/LF?
readLine blocks until a line-terminating character is read.
Related
I use layered architecture. I create a server. I want the server to listen when the data arrives.
This is my server code in the DataAccess layer.
public class ServerDal : IServerDal
{
private TcpListener server;
private TcpClient client = new TcpClient();
public bool ServerStart(NetStatus netStatus)
{
bool status = false;
try
{
server = new TcpListener(IPAddress.Parse(netStatus.IPAddress), netStatus.Port);
server.Start();
status = true;
}
catch (SocketException ex)
{
Console.WriteLine("Starting Server Error..." + ex);
status = false;
}
return status;
}
public string ReceiveAndSend(NetStatus netStatus)
{
Byte[] bytes = new Byte[1024];
String data = null;
Mutex mutex = new Mutex(false, "TcpIpReceive");
mutex.WaitOne();
if (!client.Connected)
client = server.AcceptTcpClient();
try
{
NetworkStream stream = client.GetStream();
int i;
if ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
Console.WriteLine("Received: " + data);
}
}
catch (Exception ex)
{
Console.WriteLine("Connection Error..." + ex);
client.Close();
}
finally
{
mutex.ReleaseMutex();
}
return data;
}
}
I can listen to the client that first connects to the server. When the first connecting client disconnects, I can listen to the second connecting client.
I want to listen when both clients send data. How can I do that ? Thanks for your help.
I fixed the problem.
static List<TcpClient> tcpClients = new List<TcpClient>();
public void ReceiveMessage(NetStatus netStatus)
{
try {
TcpClient tcpClient = server.AcceptTcpClient();
tcpClients.Add(tcpClient);
Thread thread = new Thread(unused => ClientListener(tcpClient, netStatus));
thread.Start();
}
catch(Exception ex) {
Console.WriteLine("[ERROR...] Server Receive Error = {0} ", ex.Message);
}
}
public void ClientListener(object obj, NetStatus netStatus)
{
try
{
TcpClient tcpClient = (TcpClient)obj;
StreamReader reader = new StreamReader(tcpClient.GetStream());
while(true)
{
string message = null;
message = reader.ReadLine();
if(message!=null)
{
netStatus.IncommingMessage = message;
Console.WriteLine("[INFO....] Received Data = {0}", message);
}
}
}
catch(Exception ex)
{
Console.WriteLine("[ERROR....] ClientListener Error = {0}", ex.Message);
}
}
I am new to C#.
I am trying to establish a TCP communication using TLS over LAN but have no idea how to do it. I have done the same in java using following code :
SSLSocketFactory sslSocketFactory = Util.BuildSslSocketFactoryForLAN(getApplicationContext());
Socket tcpSocket = sslSocketFactory.createSocket("IP address", "port");
is = tcpSocket.getInputStream();
OutputStream os = tcpSocket.getOutputStream();
devicePairingReq = Util.hexStringToByteArray("9F" + data);
os.write(devicePairingReq);
os.flush();
while (true) {
tcpSocket.setSoTimeout(1000 * 90);
resp = new byte[15];
test = is.read(resp);
tcpSocket.close();
public static SSLSocketFactory BuildSslSocketFactoryForLAN(Context context) {
try {
SSLContext sslContext = SSLContext.getInstance("TLS");
CertificateFactory cf = CertificateFactory.getInstance("X.509");
InputStream is = context.getResources().getAssets().open("name.pem");
InputStream caInput = new BufferedInputStream(is);
Certificate ca;
try {
ca = cf.generateCertificate(caInput);
} finally {
caInput.close();
}
String keyStoreType = KeyStore.getDefaultType();
KeyStore keyStore = KeyStore.getInstance(keyStoreType);
keyStore.load(null, null);
keyStore.setCertificateEntry("ca", ca);
String tmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm();
TrustManagerFactory tmf = TrustManagerFactory.getInstance(tmfAlgorithm);
tmf.init(keyStore);
sslContext.init(null, tmf.getTrustManagers(), null);
SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();
return sslSocketFactory;
} catch (CertificateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (KeyStoreException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (KeyManagementException e) {
e.printStackTrace();
}
return null;
}
I am totally new to C# so have very little idea about it.
I am trying to sent a message to tcp server from mobile client over LAN.
I'm trying to make a server client using a local console server on my pc and a client on windows phone 8.1. The problem that I have is that I don't know how to read the incoming data from the client. I've searched the internet and read serveral microsoft tutorials but they do not explain how to read the incoming data in the server. Here's what I have.
Client on windows phone 8.1:
private async void tryConnect()
{
if (connected)
{
StatusLabel.Text = "Already connected";
return;
}
try
{
// serverHostnameString = "127.0.0.1"
// serverPort = "1330"
StatusLabel.Text = "Trying to connect ...";
serverHost = new HostName(serverHostnameString);
// Try to connect to the
await clientSocket.ConnectAsync(serverHost, serverPort);
connected = true;
StatusLabel.Text = "Connection established" + Environment.NewLine;
}
catch (Exception exception)
{
// If this is an unknown status,
// it means that the error is fatal and retry will likely fail.
if (SocketError.GetStatus(exception.HResult) == SocketErrorStatus.Unknown)
{
throw;
}
StatusLabel.Text = "Connect failed with error: " + exception.Message;
// Could retry the connection, but for this simple example
// just close the socket.
closing = true;
// the Close method is mapped to the C# Dispose
clientSocket.Dispose();
clientSocket = null;
}
}
private async void sendData(string data)
{
if (!connected)
{
StatusLabel.Text = "Must be connected to send!";
return;
}
UInt32 len = 0; // Gets the UTF-8 string length.
try
{
StatusLabel.Text = "Trying to send data ...";
// add a newline to the text to send
string sendData = "jo";
DataWriter writer = new DataWriter(clientSocket.OutputStream);
len = writer.MeasureString(sendData); // Gets the UTF-8 string length.
// Call StoreAsync method to store the data to a backing stream
await writer.StoreAsync();
StatusLabel.Text = "Data was sent" + Environment.NewLine;
// detach the stream and close it
writer.DetachStream();
writer.Dispose();
}
catch (Exception exception)
{
// If this is an unknown status,
// it means that the error is fatal and retry will likely fail.
if (SocketError.GetStatus(exception.HResult) == SocketErrorStatus.Unknown)
{
throw;
}
StatusLabel.Text = "Send data or receive failed with error: " + exception.Message;
// Could retry the connection, but for this simple example
// just close the socket.
closing = true;
clientSocket.Dispose();
clientSocket = null;
connected = false;
}
}
(from http://msdn.microsoft.com/en-us/library/windows/apps/xaml/jj150599.aspx)
And the server:
public class Server
{
private TcpClient incomingClient;
public Server()
{
TcpListener listener = new TcpListener(IPAddress.Parse("127.0.0.1"), 1330);
listener.Start();
Console.WriteLine("Waiting for connection...");
while (true)
{
//AcceptTcpClient waits for a connection from the client
incomingClient = listener.AcceptTcpClient();
//start a new thread to handle this connection so we can go back to waiting for another client
Thread thread = new Thread(HandleClientThread);
thread.IsBackground = true;
thread.Start(incomingClient);
}
}
private void HandleClientThread(object obj)
{
TcpClient client = obj as TcpClient;
Console.WriteLine("Connection found!");
while (true)
{
//how to read and send data back?
}
}
}
It comes to the point where the server prints 'Connection found!', but I don't know how to go further.
Any help is appreciated!
EDIT:
Now my handleclientthread method looks like this:
private void HandleClientThread(object obj)
{
TcpClient client = obj as TcpClient;
netStream = client.GetStream();
byte[] rcvBuffer = new byte[500]; // Receive buffer
int bytesRcvd; // Received byte count
int totalBytesEchoed = 0;
Console.WriteLine("Connection found!");
while (true)
{
while ((bytesRcvd = netStream.Read(rcvBuffer, 0, rcvBuffer.Length)) > 0)
{
netStream.Write(rcvBuffer, 0, bytesRcvd);
totalBytesEchoed += bytesRcvd;
}
Console.WriteLine(totalBytesEchoed);
}
}
But it still doesn't write the bytes to the console
So... after a lot of searching the internet I have found a solution...
Server: to read from the server and send data back to the phone:
// method in a new thread, for each connection
private void HandleClientThread(object obj)
{
TcpClient client = obj as TcpClient;
netStream = client.GetStream();
Console.WriteLine("Connection found!");
while (true)
{
// read data
byte[] buffer = new byte[1024];
int totalRead = 0;
do
{
int read = client.GetStream().Read(buffer, totalRead, buffer.Length - totalRead);
totalRead += read;
} while (client.GetStream().DataAvailable);
string received = Encoding.ASCII.GetString(buffer, 0, totalRead);
Console.WriteLine("\nResponse from client: {0}", received);
// do some actions
byte[] bytes = Encoding.ASCII.GetBytes(received);
// send data back
client.GetStream().WriteAsync(bytes, 0, bytes.Length);
}
}
Phone(client): to send messages from the phone and read the messages from server:
private async void sendData(string dataToSend)
// import for AsBuffer(): using System.Runtime.InteropServices.WindowsRuntime;
{
if (!connected)
{
StatusLabel.Text = "Status: Must be connected to send!";
return;
}
try
{
byte[] data = GetBytes(dataToSend);
IBuffer buffer = data.AsBuffer();
StatusLabel.Text = "Status: Trying to send data ...";
await clientSocket.OutputStream.WriteAsync(buffer);
StatusLabel.Text = "Status: Data was sent" + Environment.NewLine;
}
catch (Exception exception)
{
if (SocketError.GetStatus(exception.HResult) == SocketErrorStatus.Unknown)
{
throw;
}
StatusLabel.Text = "Status: Send data or receive failed with error: " + exception.Message;
closing = true;
clientSocket.Dispose();
clientSocket = null;
connected = false;
}
readData();
}
private async void readData()
{
StatusLabel.Text = "Trying to receive data ...";
try
{
IBuffer buffer = new byte[1024].AsBuffer();
await clientSocket.InputStream.ReadAsync(buffer, buffer.Capacity, InputStreamOptions.Partial);
byte[] result = buffer.ToArray();
StatusLabel.Text = GetString(result);
}
catch (Exception exception)
{
if (SocketError.GetStatus(exception.HResult) == SocketErrorStatus.Unknown)
{
throw;
}
StatusLabel.Text = "Receive failed with error: " + exception.Message;
closing = true;
clientSocket.Dispose();
clientSocket = null;
connected = false;
}
}
The 'await clientSocket.InputStream.ReadAsync(buffer, buffer.Capacity, InputStreamOptions.Partial)' command in the readData method was very unclear for me. I didn't know you had to make a new buffer, and the ReadAsync-method fills it(as i inderstand it). Found it here: StreamSocket.InputStreamOptions.ReadAsync hangs when using Wait()
first: I hope my english is not so bad (maybe it's gerglish; german grammer with english vocabularies)
I'm writing an server in java for android which communicates with an client written in c# running on WindowsCE 5. The big problem is that sometimes especially or maybe only if the network is unstable my java server still blocks in the accept-Method also when the client is sending data. I simulated the unstable network by switch off and on my virtual router over which both devices communicate. I also could recognize that the c#-program hangs in the write- or read-method or throws an IOException also when the network is switched on and my server is hearing on the expected port.
Here is the source code of the client:
Some information:
1. It is sending 10000 messages only for testing
static void Main(string[] args)
{
string server = ...;
int port = 12000;
String outputStr = "";
NetworkStream stream = null;
for (int i = 0; i < 10000; i++)
{
TcpClient client = null;
String messageToSend = ...
try
{
IPAddress ipAddress = IPAddress.Parse(server);
IPEndPoint ipEndPoint = new IPEndPoint(ipAddress, port);
AutoResetEvent connectDone = new AutoResetEvent(false);
client = new TcpClient();
client.Client.BeginConnect(ipEndPoint,
new AsyncCallback(
delegate(IAsyncResult ar)
{
try
{
client.Client.EndConnect(ar);
connectDone.Set();
}
catch (Exception ex)
{}
}
), client.Client);
if (!connectDone.WaitOne(5000, false))
{
outputStr = "NOTConnected";
}
Byte[] data = System.Text.Encoding.UTF8.GetBytes(messageToSend);
stream = client.GetStream();
try
{
stream.Write(data, 0, data.Length);
data = new Byte[2048];
int bytes = stream.Read(data, 0, data.Length);
string responseData = System.Text.Encoding.UTF8.GetString(data, 0, bytes);
outputStr = responseData;
}
catch (IOException ex)
{
outputStr = ex.Message;
}
}
}
catch (SocketException ex)
{
outputStr = ex.Message;
}
catch (Exception ex)
{
outputStr = ex.Message;
}
finally
{
if (stream != null) stream.Close();
}
System.Threading.Thread.Sleep(200);
}
Console.WriteLine("\n Press Enter to continue... " + outputStr);
Console.Read();
}
And my source code of the server:
Some information. My servlet normally is an inner class and first checks if the devices is connected to a router. If it is it starting to here on a port. If not it goes to wait mode (see _sendToSleep()). If devices is reconnected the activity can wakes it up by notify. If it looses again the connection the Activity will cause a SocketException by closing the socket so the servlet can leave the accept-method.
public class ServletThread extends Thread {
private int port;
private ServerSocket serverSocket;
private Socket socket;
public ServletThread(int port) throws IOException {
super();
this.port = port;
serverSocket = new ServerSocket(port);
}
private void checkConnectivity(BufferedWriter out) {
try {
String outgoingMsg = "connected";
out.write(outgoingMsg);
out.flush();
} catch (IOException e) {
Log.e(TAG, "connectivity exception " + e.getMessage());
}
}
private void readStream(Scanner scanner) throws IOException {
String str = "";
while (scanner.hasNext()) {
str += scanner.nextLine();
}
final String fTicket = str;
runOnUiThread(new Runnable() {
#Override
public void run() {
if (MyActivity.this.isFinishing()) {
return;
}
// do something
}
});
}
private void _sendToSleep() {
try {
synchronized (this) {
this.wait();
}
} catch (InterruptedException e) {
this.interrupt();
}
}
#Override
public void interrupt() {
super.interrupt();
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
Log.e(TAG, ""+e.getMessage());
}
}
}
#Override
public void run() {
try {
serverSocket = new ServerSocket(port);
} catch (IOException ex) {
Log.e(TAG,""+ex.getMessage());
}
while (!isInterrupted()) {
if (connectionState != NetworkInfo.State.CONNECTED) {
_sendToSleep();
} else {
BufferedWriter out = null;
Scanner scanner = null;
try {
socket = serverSocket.accept();
out = new BufferedWriter(new OutputStreamWriter(
socket.getOutputStream()));
scanner = new Scanner(socket.getInputStream());
checkConnectivity(out);
readStream(scanner);
} catch (IOException ex) {
Log.e(TAG, ex.getMessage() + "");
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
Log.e(TAG, "exception on close socket " + e.getMessage());
}
}
if (scanner != null) {
scanner.close();
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
Log.e(TAG, ""+e.getMessage());
}
}
}
}
}
}
}
After isolating the bug, i did some changes:
c# instead of stream = client.getStream
(using Stream = client.getStream()) {
...
stream.WriteTimeout = 1000;
stream.ReadTimeout = 1000;
...
}
in java changes in the _sendToSleep()
private void _sendToSleep() {
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
Log.e(TAG, "failed to close serverSocket " + e.getMessage());
}
}
try {
synchronized (this) {
this.wait();
}
} catch (InterruptedException e) {
this.interrupt();
}
try {
serverSocket = new ServerSocket(port);
} catch (IOException e) {
Log.e(TAG, "failed to open serversocket " + e.getMessage());
}
}
It became better, means, I could not reproduce the problem.
My questions:
Why did it the client hang? (maybe a synchronisation problem on servlet-side and client between socketserver and wlan-adapter after reconnecting several times, so that the servlet cannot get any data???)
And do my changes solve the problem.
Thanking you in anticipation!
I am making a program in 2 parts.
Part 1: C# server-socket Application running on PC, listening for commands, and acts accordingly.
Part 2: Java client-socket application running on phone, that sends a command to the pc, when a button is pressed.
Currently, i can send commands from the client to the server, and its all good.
But my problem is this: When i send a specific command to the server, i want the server to reply to the client, and the client to read that reply.
Thing just is, when the client tries to read, it time-outs.
Java client program:
class ClientThread implements Runnable
{
public void run()
{
try
{
Socket socket = new Socket(serverIpAddress, serverPort);
socket.setSoTimeout(5000);
while (true)
{
try
{
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
Log.d("Nicklas", "Out it goes");
out.println(Command);
if (Command == "CMD:GetOptions<EOF>")
{
Log.d("Nicklas", "Getting options");
try
{
Log.d("Nicklas", "Line 1");
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
Log.d("Nicklas", "Line 2");
String answer = in.readLine();
Log.d("Nicklas", "answer = " + answer );
}
catch (Exception ee)
{
Log.d("Nicklasasasas", ee.toString());
}
}
break;
}
catch (Exception e)
{
Log.d("Nicklas", "CAE = " + e.toString());
break;
}
}
socket.close();
}
catch (ConnectException ee)
{
Log.d("Nicklas", "Kunne ikke forbinde");
}
catch (Exception e)
{
Log.d("Nicklasssssss", e.toString());
}
}
}
This is called with:
Thread cThread = new Thread(new ClientThread());
cThread.start();
And uses the global variable "Command", which will contain different information, depending on what button was pressed.
The program fails on the line "String answer = in.readline();" with the exception "java.net.SocketTimeoutException".
This is the C# Server part of the program:
private void ListenForClients()
{
this.tcpListener.Start();
while (true)
{
//blocks until a client has connected to the server
TcpClient client = this.tcpListener.AcceptTcpClient();
//create a thread to handle communication
//with connected client
Thread clientThread = new Thread(new ParameterizedThreadStart(HandleClientComm));
clientThread.Start(client);
}
}
private void HandleClientComm(object client)
{
TcpClient tcpClient = (TcpClient)client;
NetworkStream clientStream = tcpClient.GetStream();
byte[] message = new byte[4096];
int bytesRead;
while (true)
{
bytesRead = 0;
try
{
//blocks until a client sends a message
bytesRead = clientStream.Read(message, 0, 4096);
}
catch
{
//a socket error has occured
break;
}
if (bytesRead == 0)
{
//the client has disconnected from the server
break;
}
//message has successfully been received
ASCIIEncoding encoder = new ASCIIEncoding();
//System.Diagnostics.Debug.WriteLine(encoder.GetString(message, 0, bytesRead));
string Input = (encoder.GetString(message, 0, bytesRead));
Input = Input.Trim();
object[] obj = new object[1];
obj[0] = Input;
if (Input == "CMD:GetOptions<EOF>")
{
try
{
byte[] buffer = encoder.GetBytes("CMD:Accepted");
clientStream.Write(buffer, 0, buffer.Length);
clientStream.Flush();
MessageBox.Show("Client program asked for reply");
}
catch (Exception e)
{
MessageBox.Show("Oh it no work!: " + e.ToString());
}
}
else
{
Udfor(Input);
}
}
tcpClient.Close();
}
Called with the following, in the Form1()
this.tcpListener = new TcpListener(IPAddress.Any, 4532);
this.listenThread = new Thread(new ThreadStart(ListenForClients));
this.listenThread.Start();
The C# Server seems to work fine, and does show the messagebox "client program asked for reply"
Anyone who can spot the error?
I figured it out!
The problem was the C#. When the server sent back the command "CMD:Accepted", it never closed the socket, so the android application had no idea of telling if it was done reading! Closing the socket right after flushing + of course not closing it again if i already did, did the trick!