I have written a code for client server using tcp/sockets in c# which is working perfectly fine. My problem is that why I am able to send only limited size data from client to server at a single instance.
Following is my server code
public class AsynchIOServer
{
// server port number
const int port = 8001;
// server ip address
const string ip = "127.0.0.1";
const int maxBuffer = 10000;
static IPAddress ipAddress = IPAddress.Parse(ip);
static TcpListener tcpListener = new TcpListener(ipAddress, port);
static void Listeners()
{
try
{
Socket socketForClient = tcpListener.AcceptSocket();
if (socketForClient.Connected)
{
Console.WriteLine("Client : " + socketForClient.RemoteEndPoint + " is now connected to server.");
NetworkStream networkStream = new NetworkStream(socketForClient);
System.IO.StreamWriter streamWriter = new System.IO.StreamWriter(networkStream);
System.IO.StreamReader streamReader = new System.IO.StreamReader(networkStream);
while (true)
{
string theString = streamReader.ReadLine();
if (theString != "exit")
{
// original message from client
Console.WriteLine("------------------------------------------------------------------------------");
Console.WriteLine("Message recieved from client(" + socketForClient.RemoteEndPoint + ") : " + theString);
// ASCII code for the message from client
Console.Write("ASCII Code for message is : ");
foreach (char c in theString)
{
Console.Write(System.Convert.ToInt32(c) + " ");
}
// Hex value of message from client
string hex = "";
foreach (char c in theString)
{
int tmp = c;
hex += String.Format("{0:x2}", (uint)System.Convert.ToUInt32(tmp.ToString()));
}
Console.WriteLine();
Console.WriteLine("Hex Code for the message from client : " + hex);
//sending acknowledgement to client
Console.WriteLine();
socketForClient.Send(new ASCIIEncoding().GetBytes(/*"The string was recieved from Client(" + socketForClient.RemoteEndPoint + ") : " + */theString));
} // end of if loop
// if exit from client
else
{
Console.WriteLine();
Console.WriteLine("Client " + socketForClient.RemoteEndPoint + " has exited");
break;
}
} // end of while loop
streamReader.Close();
networkStream.Close();
streamWriter.Close();
} // end of if loop
socketForClient.Close();
Console.WriteLine();
// Console.WriteLine("Press any key to exit from server program");
Console.ReadKey();
} // end of try loop
catch (Exception e)
{
Console.WriteLine("The process failed: {0}", e.ToString());
Console.WriteLine("Message not received from client");
}
} // end of Listener loop
// Number of clients that can connect to the server
public static void Main()
{
tcpListener.Start();
Console.WriteLine("********** This is the Server program **********");
Console.Write("Number of Clients that can connect to Server : ");
int numberOfClientsYouNeedToConnect = int.Parse(Console.ReadLine());
for (int i = 0; i < numberOfClientsYouNeedToConnect; i++)
{
Thread newThread = new Thread(new ThreadStart(Listeners));
newThread.Start();
}
Console.WriteLine();
} // end of Min Loop
} // end of public class AsynchIOServer
while my client code is
public class Client
{
// For acknowledgement from server
const int maxBuffer = 1000;
static public void Main(string[] Args)
{
// ip address of server to which client should be connected
string ip;
// port number at which server is listening for client connection
int port;
Console.Write("Enter the ip address: ");
ip = Console.In.ReadLine();
Console.Write("Enter the port number: ");
port = int.Parse(Console.In.ReadLine());
TcpClient socketForServer;
try
{
// connect to server at ipaddress ip and port number port
socketForServer = new TcpClient(ip, port);
}
catch
{
Console.WriteLine("Failed to connect to server at {0}:{1}", ip , port);
Console.ReadLine();
return;
}
// Initializing StreamReader and StreamWriter for sending or reading message from server
NetworkStream networkStream = socketForServer.GetStream();
System.IO.StreamReader streamReader = new System.IO.StreamReader(networkStream);
System.IO.StreamWriter streamWriter = new System.IO.StreamWriter(networkStream);
try
{
Console.WriteLine();
Console.WriteLine("---Begin sending message(type 'exit' to disconnect from server)---");
Console.WriteLine();
Console.Write("Type message : ");
string str = Console.ReadLine();
while (str != "exit")
{
streamWriter.WriteLine(str);
streamWriter.Flush();
// For receiving acknowledgement from server
byte[] receiveBuffer = new byte[maxBuffer];
int k = networkStream.Read(receiveBuffer, 0, maxBuffer);
for (int i = 0; i < k; i++)
Console.Write(/*Convert.ToChar(*/receiveBuffer[i]);
Console.WriteLine();
Console.WriteLine("------------------------------------------------------");
Console.Write("Type message : ");
str = Console.ReadLine();
}
// For client to close connection with server
if (str == "exit")
{
streamWriter.WriteLine(str);
streamWriter.Flush();
}
} // end of try loop
catch
{
Console.WriteLine("Exception reading from Server");
}
// exit the client
networkStream.Close();
Console.WriteLine("Press any key to exit from client program");
Console.ReadKey();
} // End of Main loop
} // End of public class Client
Now when I run my program I enter following binary to be sent from client as first message
Type message : 11111111111111111111111111111111111111111111111111111111111111111
11111111111111111111111111111111111111111111111111111111111111111111111111111111
11111111111111111111111111111111111111111111111111111111111111111111111111111111
11111111111111111111111111111
Problem is that it doesn't allow me enter more binary data. I can send more binary data if I want to send by pressing enter and then sending as 2nd message. But I want to send it as single message. So is their any limit to send more data at single instance over tcp/sockets?
Your assessment of the problem is wrong. There are no messages -- TCP has no such thing as application-level messages because TCP is not a message protocol, it's a byte stream protocol that provides a stream of bytes, not messages. There is no such thing as "send it as single message" nor is there such as thing as "sending as 2nd message". It's just sending bytes and receiving bytes. If you want to receive more bytes, call receive again.
If you want to implement messages, you can do so. But you have to do it. You have to define, specify, and implement a protocol that sends and receives messages on top of TCP. You have to specify how messages will be delimited, send delimited messages, and write receive code to detect the delimiters and assemble the received byte stream into messages. It won't happen by itself.
The simplest solution is to read and write lines delimited by newline characters, assuming your "messages" can't contain newlines.
That has to do with the ReadLine method limiting input to 256 characters, see Remarks section for a workaround:
http://msdn.microsoft.com/en-us/library/system.console.readline.aspx
edit: typo
Related
I'm writing app on android, which would communicate with c# server via TCP protocol. My code works fine when I use wi-fi and now I want to change it that it would work even if android client would use mobile data
Server in c# (only recive and send data):
static void Main(string[] args)
{
//setup
Program prog = new Program();//to run non-static void from static context
//main server
try
{
IPAddress ipAd = IPAddress.Parse("192.168.x.xxx");
// Initializes the Listener
TcpListener myList = new TcpListener(ipAd, 11000);
/* Start Listeneting at the specified port */
myList.Start();
//label com
com:
//accept connection
Socket s = myList.AcceptSocket();
Console.WriteLine("Connection accepted from " + s.RemoteEndPoint);
//recive data
byte[] b = new byte[100];
int k = s.Receive(b);
char cc = ' ';
string text = null;//wil produce recived text
Console.Write("Recieved: ");
for (int i = 0; i < k - 1; i++)
{
Console.Write(Convert.ToChar(b[i]));
cc = Convert.ToChar(b[i]);
text += cc.ToString();
}
Console.WriteLine();
//analyze text
string reply = prog.analyzeText(text);
//send reply
ASCIIEncoding asen = new ASCIIEncoding();//is using to encode reply<string> to possible to send format
s.Send(asen.GetBytes(reply));//send
s.Close();
/* clean up */
goto com;
s.Close();
myList.Stop();
Console.ReadLine();
}
catch (Exception e)
{
Console.WriteLine("Error: " + e.StackTrace);
Console.ReadLine();
}
}
and android client code:
private String connectSocket(String msg) {//send and receive data from server
try {
InetAddress serverAddr = InetAddress.getByName("192.168.x.xxx");
Socket socket = new Socket(serverAddr, 11000);
//define PrintWriter
PrintWriter out = null;
try {
out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
final BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
out.println(msg);
String text = "";
String finalText = "";
while ((text = in.readLine()) != null) {
finalText += text;
}
socket.close();
return finalText;
} catch (Exception e) {
Toast.makeText(getApplicationContext(),"Something went wrong.\nTry again in few minutes",Toast.LENGTH_SHORT).show();
return "exception";
} finally {
socket.close();
}
} catch (UnknownHostException e) {
return "UnknownHostException";
} catch (IOException e) {
return "IOException";
}
}
PS. sorry for my english, but I started learning it only 1 year ago
There's no code changes needed. You might need to set up your network correctly so there's no firewalls in the way around your test server (and that may include talking to your ISP, if they have a firewall preventing incoming connections). But standard socket communication works over wifi or mobile.
i have a problem i am unable to resolve as my c# knowledge is not very good.
I found some code on the internet and modified it according to my needs.
My problem is that when i send messages to clients only one receives the message, then the next message is received by another client and so on.
I want to send same message to all connected clients without losing any data.
Server
using System;
using System.Net.Sockets;
using System.Threading;
public class AsynchIOServer
{
static TcpListener tcpListener = new TcpListener(10);
static void Listeners()
{
Socket socketForClient = tcpListener.AcceptSocket();
if (socketForClient.Connected)
{
Console.WriteLine("Client:"+socketForClient.RemoteEndPoint+" now connected to server.");
NetworkStream networkStream = new NetworkStream(socketForClient);
System.IO.StreamWriter streamWriter =
new System.IO.StreamWriter(networkStream);
System.IO.StreamReader streamReader =
new System.IO.StreamReader(networkStream);
////here we send message to client
while (true){
Console.WriteLine("type your message to be recieved by client:");
string theString = Console.ReadLine();
streamWriter.WriteLine(theString);
////Console.WriteLine(theString);
streamWriter.Flush();
}
streamReader.Close();
networkStream.Close();
streamWriter.Close();
}
socketForClient.Close();
Console.WriteLine("Press any key to exit from server program");
Console.ReadKey();
}
public static void Main()
{
//TcpListener tcpListener = new TcpListener(10);
tcpListener.Start();
Console.WriteLine("************This is Server program************");
Console.WriteLine("Hoe many clients are going to connect to this server?:");
int numberOfClientsYouNeedToConnect =int.Parse( Console.ReadLine());
for (int i = 0; i < numberOfClientsYouNeedToConnect; i++)
{
Thread newThread = new Thread(new ThreadStart(Listeners));
newThread.Start();
}
}
}
Client:
using System;
using System.Net.Sockets;
using System.Threading;
public class Client
{
static public void Main(string[] Args)
{
TcpClient socketForServer;
try
{
socketForServer = new TcpClient("localHost", 10);
}
catch
{
Console.WriteLine(
"Failed to connect to server at {0}:999", "localhost");
return;
}
NetworkStream networkStream = socketForServer.GetStream();
System.IO.StreamReader streamReader =
new System.IO.StreamReader(networkStream);
System.IO.StreamWriter streamWriter =
new System.IO.StreamWriter(networkStream);
Console.WriteLine("*******This is client program who is connected to localhost on port No:10*****");
try
{
string outputString;
// read the data from the host and display it
{
while (true)
{
outputString = streamReader.ReadLine();
Console.WriteLine("Message Recieved by server:" + outputString);
streamWriter.Flush();
}
}
}
catch
{
Console.WriteLine("Exception reading from Server");
}
// tidy up
networkStream.Close();
Console.WriteLine("Press any key to exit from client program");
Console.ReadKey();
}
private static string GetData()
{
//Ack from sql server
return "ack";
}
}
Thank you
simple working multi-threaded server:
static void Process(Socket client) {
Console.WriteLine("Incoming connection from " + client.RemoteEndPoint);
const int maxMessageSize = 1024;
byte[] response;
int received;
while (true) {
// Send message to the client:
Console.Write("Server: ");
client.Send(Encoding.ASCII.GetBytes(Console.ReadLine()));
Console.WriteLine();
// Receive message from the server:
response = new byte[maxMessageSize];
received = client.Receive(response);
if (received == 0) {
Console.WriteLine("Client closed connection!");
return;
}
List<byte> respBytesList = new List<byte>(response);
respBytesList.RemoveRange(received, maxMessageSize - received); // truncate zero end
Console.WriteLine("Client (" + client.RemoteEndPoint + "+: " + Encoding.ASCII.GetString(respBytesList.ToArray()));
}
}
static void Main(string[] args) {
int backlog = -1, port = 2222;
Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
server.ReceiveTimeout = -1;
// Start listening.
try {
server.Bind(new IPEndPoint(IPAddress.Any, port));
server.Listen(backlog);
}
catch (Exception) {
Console.WriteLine("Listening failed!");
Console.ReadKey();
return;
}
Console.WriteLine("Start listening...");
while(true) {
Socket client = server.Accept();
new System.Threading.Thread(() => {
try { Process(client); } catch (Exception ex) { Console.WriteLine("Client connection processing error: " + ex.Message); }
}).Start();
}
//Console.WriteLine("Press any key for exit...");
//Console.ReadKey();
}
And client:
static void WorkWithServer(Socket server) {
const int maxMessageSize = 1024;
byte[] response;
int received;
while(true) {
try {
// Receive message from the server:
response = new byte[maxMessageSize];
received = server.Receive(response);
if (received == 0) {
Console.WriteLine("Server closed connection.");
return;
}
List<byte> respBytesList = new List<byte>(response);
respBytesList.RemoveRange(received, maxMessageSize - received); // truncate zero end
Console.WriteLine("Server: " + Encoding.ASCII.GetString(respBytesList.ToArray()));
// Send message to the server:
Console.Write("You: ");
server.Send(Encoding.ASCII.GetBytes(Console.ReadLine()));
Console.WriteLine();
}
catch (Exception ex) {
Console.WriteLine("Error: " + ex.Message);
return;
}
}
}
static void Main(string[] args) {
IPEndPoint serverEp = new IPEndPoint(IPAddress.Parse("192.168.1.2"), 2222);
Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
server.ReceiveTimeout = -1;
// Connect to the server.
try { server.Connect(serverEp); }
catch (Exception) {
Console.WriteLine("Establish connection with server (" + serverEp + ") failed!");
Console.ReadKey();
return;
}
Console.WriteLine("Connection with server (" + serverEp + ") established!");
WorkWithServer(server);
Console.WriteLine("Press any key for exit...");
Console.ReadKey();
}
Edit as you need.
Your code is wrong.
First of all I'll give you some insight of how it's wrong and why it's not working the way you want.
You're creating n number of threads, and making them ALL wait for a connection. What if you exhaust the number of threads? What if any of them exits unexpectedly?
You are also sending the data wrong. By using Console.ReadLine you aren't passing the data through multiple threads and reading the line in each one, instead, the first one that calls Console.ReadLine will be the one that's going to receive it. This means you'll only be sending to only one Socket.
It's not ideal how you're managing this. There are dozens if not hundreds of multithreaded socket server/client available online, and I'd invite you to research a little bit more. But first I'd like you to research more about Thread/Task in C#.
I am trying to learn the server/client paradigm. I have created a server that listens for connection and input on given port.
My problem is that, when a client connects and sends a message, the server closes the connection, and stops listening for input. What I want, is that when a clients sends a message, the sever should not close the connection, but still keep getting input from the connected client. I know that I can only handle one client at a time, since I am not creating a Thread for each client, but this should not cause the server to close connection as soon as the client sends a message.
Here is my server code:
public void startServer() {
try {
IPAddress iAd = IPAddress.Parse("127.0.0.10");
TcpListener tcpListner = new TcpListener(iAd, 9000);
tcpListner.Start();
Console.WriteLine("The server is running on port: 9000");
Console.WriteLine("The local End point is: " + tcpListner.LocalEndpoint + "\nWaiting for a connection");
Socket socket = tcpListner.AcceptSocket();
Console.WriteLine("\nConnection from client: " + socket.RemoteEndPoint);
byte[] b =new byte[100];
int k = socket.Receive(b);
for (int i=0;i<k;i++) {
Console.Write("Recieved: " + Convert.ToChar(b[i]));
}
ASCIIEncoding asen=new ASCIIEncoding();
socket.Send(asen.GetBytes("The string was recieved by the server."));
Console.WriteLine("\nSent Acknowledgement");
/* clean up */
socket.Close();
tcpListner.Stop();
} catch(Exception e) {
Console.WriteLine(e.Message);
}
}
And the client code
public void StartClient(string servToConnectTo, int port) {
try{
client.Connect(servToConnectTo, port);
Console.WriteLine("Connected to server: " + servToConnectTo + " on port: " + port);
Console.WriteLine ("Write input to server...");
String input = Console.ReadLine();
Stream stream = client.GetStream();
ASCIIEncoding asen = new ASCIIEncoding();
byte[] b = asen.GetBytes(input);
Console.WriteLine("Sending...");
stream.Write(b, 0, b.Length);
byte[] bb = new byte[100];
int k = stream.Read(bb, 0, 100);
for(int i = 0; i < k; i++) {
Console.Write(Convert.ToChar(bb[i]));
}
client.Close();
} catch (Exception e) {
Console.WriteLine (e.Message);
}
}
I guess I need a while loop some place, but not sure where
I have developed TCP/IP Server in C# listening on port and a GPS device is sending the data to server.
Initially, the device sends the IMEI number to server and server acknowledges with 01. After receiving the acknowledgement by device, a new packet of data is sent to server.
I am able to get IMEI number by TCP Server and after sending acknowledgement, i am not able to receive new packet data from client. I am including my code below also. Please let me know where i am wrong.
I have tested using hercules tcp server tool and next data packet is receiving successfully but from my application it is not working.
try
{
IPAddress ipAdress = IPAddress.Parse(ConfigurationManager.AppSettings["Server"].ToString());
// You can use local IP as far as you use the
//same in client
// Initializes the Listener
TcpListener myList = new TcpListener(ipAdress, int.Parse(ConfigurationManager.AppSettings["Port"].ToString()));
for (; ; )
{ // Run forever, accepting and servicing connections
//Start Listeneting at the specified port
myList.Start();
Console.WriteLine("Server running - Port: 8000");
Console.WriteLine("Local end point:" + myList.LocalEndpoint);
Console.WriteLine("Waiting for connections...");
Socket socket = myList.AcceptSocket();
// When accepted
Console.WriteLine("Connection accepted from " + socket.RemoteEndPoint);
byte[] b = new byte[1000];
int k = socket.Receive(b);
Console.WriteLine("echoed {0} bytes.", k);
Console.WriteLine("Reading IMEI....");
string hexStr = ConvertAsciiToHex(Encoding.ASCII.GetString(b, 0, b.Length));
File.WriteAllText(#"C:\ClientFiles\testIMEI", hexStr);
ASCIIEncoding asen = new ASCIIEncoding();
string response = "01";
Console.WriteLine("Ackowledgement Data - " + response);
//
int sentBytes = socket.Send(asen.GetBytes(response));
Console.WriteLine("Acknowledgement data sent!\n");
int count = 0;
while (socket.Poll(-1, SelectMode.SelectRead))
{
b = new byte[1000];
k = socket.Receive(b);
if (k > 0)
{
count++;
Console.WriteLine("Reading Client Data - Count - " + count.ToString() + " and lenght " + k.ToString());
hexStr = ConvertAsciiToHex(Encoding.ASCII.GetString(b, 0, b.Length));
File.WriteAllText(#"C:\ClientFiles\testData" + count.ToString(), hexStr);
}
}
socket.Shutdown(SocketShutdown.Both);
socket.Close();
}
myList.Stop();
}
catch (Exception ex)
{
File.WriteAllText(#"C:\ClientFiles\Error.txt", ex.Message + "****" + ex.InnerException);
}
I don't see any error in the program, except these comments:
// Don't use the b.Length in this command:
string hexStr = ConvertAsciiToHex(Encoding.ASCII.GetString(b, 0, b.Length));
// use k instead, the numbers actually read, not the length of the buffer.
string hexStr = ConvertAsciiToHex(Encoding.ASCII.GetString(b, 0, k));
while (socket.Poll(-1, SelectMode.SelectRead))
{
// b has been allocated, don't need this
// b = new byte[1000];
k = socket.Receive(b);
if (k > 0)
{
count++;
Console.WriteLine("Reading Client Data - Count - " + count.ToString() + " and lenght " + k.ToString();
// use k not Length
hexStr = ConvertAsciiToHex(Encoding.ASCII.GetString(b, 0, k /*b.Length*/));
File.WriteAllText(#"C:\ClientFiles\testData" + count.ToString(), hexStr);
}
}
Do you know if the Poll command ever returns? May be it raises an error and you are missing that one. Check it out.
I'm writting a client(Android) - server(c#) application. I get the code from here:
How to make client on Android listen to server on C#?
Everythings is working fine, when i just send message from the client to server, and from server to client (closing the socket on server side). Now, what i want is : send message to server, receive message from server, then send again a message to server. The server hangs at sending the message. If i close the socket on server side after sending, it gives a dispose error, and i can's send the data from the server.
My server code is:
/*************************************SERVER*****************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
namespace SERVER2
{
class Program
{
public static void Main()
{
try
{
IPAddress ipAd = IPAddress.Parse("192.168.2.102");
TcpListener myList = new TcpListener(ipAd, 18001);
myList.Start();
Console.WriteLine("The server is running at port 18001...");
Console.WriteLine("The local End point is :" +
myList.LocalEndpoint);
Console.WriteLine("Waiting for a connection.....");
m:
Socket s = myList.AcceptSocket();
Console.WriteLine("Connection accepted from " + s.RemoteEndPoint);
byte[] b = new byte[100];
int k = s.Receive(b);
char cc = ' ';
string test = null;
Console.WriteLine("Recieved1...");
for (int i = 0; i < k - 1; i++)
{
cc = Convert.ToChar(b[i]);
test += cc.ToString();
}
Console.WriteLine("Received characters1: "+test);
ASCIIEncoding asen = new ASCIIEncoding();
s.Send(asen.GetBytes("The string was recieved by the server."));
Console.WriteLine("\nSent Acknowledgement");
//s.Close(); <-if i enable this, i get a dispose error
k = s.Receive(b);//i get dispose error here
cc = ' ';
test = null;
Console.WriteLine("Recieved2...");
for (int i = 0; i < k - 1; i++)
{
cc = Convert.ToChar(b[i]);
test += cc.ToString();
}
Console.WriteLine("Received characters2: " + test);
/* clean up */
goto m;
s.Close();
myList.Stop();
}
catch (Exception e)
{
Console.WriteLine("Error..... " + e.Message);
}
Console.ReadLine();
}
}
}
My client code is:
/******************************CLIENT*****************************************/
Socket socket = null;
try
{
Toast.makeText(context,"IP: "+ip+" port: "+port,10000).show();
InetAddress serverAddr = InetAddress.getByName(ip);
socket = new Socket(serverAddr, port);
}
catch (UnknownHostException e1)
{
Toast.makeText(context,"UnknownHostException ",10000).show();
}
catch (IOException e1)
{
Toast.makeText(context,"IOException ",10000).show();
}
String message = "1";
PrintWriter out = null;
BufferedReader in = null;
try {
Log.d("TCP", "C: Sending: '" + message + "'");
/*write*/
out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);
out.println(message);
out.flush();
/*read*/
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String text = "";
String finalText = "";
while ((text = in.readLine()) != null)
{
finalText += text;
}
Toast.makeText(context, "FinalText: "+finalText, 10000).show();
Log.d("TCP", "C: Sent.");
Log.d("TCP", "C: Done.");
in.close();
/*write*/
out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);
out.println(message);
out.flush();
} catch(Exception e) {
Log.e("TCP", "S: Error", e);
} finally {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Thanks advanced !!!
The reason you get the dispose error is because the s.close() closes the socket, and then your next s.Receive() is trying to read from a closed socket.
Also the hang you are seeing might be caused by in.close(); in your java code. It could be closing the underlying socket. Try commenting it out and see if that fixes your hanging problem.
Not an expert in C#, but I've done my share of socket programming.
Basically what you want is 1 + n threads.
One thread that just accepts connections.
For each socket that is returned by Socket s = myList.AcceptSocket(); you want a thread for sending/receiving data and processing the messages from the socket. You could also use two threads (one that sends, one that receives (this is the asynchronous case)).
You should use the stream of the tcp client.. an example can be found here: http://msdn.microsoft.com/de-de/library/system.net.sockets.tcplistener.aspx
And don't use goto, please.
You will never reach the end lines after goto m;
Surround the code with a while loop which checks if an timeout is occured or any other checks.
The reason why the server hangs is that he waits for 100 bytes to receive.
The problem was that when the client received the message from the server , in the while part entered into an infinite loop. I modify my app like this:
My client part:
try
{
Toast.makeText(context,"IP: "+ip+" port: "+port,10000).show();
InetAddress serverAddr = InetAddress.getByName(ip);
socket = new Socket(serverAddr, port);
}
catch (UnknownHostException e1)
{
Toast.makeText(context,"UnknownHostException ",10000).show();
}
catch (IOException e1)
{
Toast.makeText(context,"IOException ",10000).show();
}
String message = "HELLO FROM CLIENT";
PrintWriter out = null;
BufferedReader in = null;
try {
Log.d("TCP", "C: Sending: '" + message + "'");
/*write*/
OutputStream ostr=socket.getOutputStream();
OutputStreamWriter outputstr=new OutputStreamWriter(ostr);
BufferedWriter buffw=new BufferedWriter(outputstr);
out = new PrintWriter(buffw ,true);
out.println("HELLO 1 FROM CLIENT");
/*read - i modify to this*/
InputStreamReader reader=new InputStreamReader(socket.getInputStream());
char[] bytesreceived=new char[50];
reader.read(bytesreceived , 0, 50);
String text="";
for (int i=0;i<bytesreceived.length;i++)
{
text+=bytesreceived[i];
}
Toast.makeText(context, "Received1: "+text.trim(), 10000).show();
Log.d("IdealLog","Received1: "+text.trim());
/*write*/
out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);
out.println("HELLO 2 FROM CLIENT");
/*read*/
reader=new InputStreamReader(socket.getInputStream());
bytesreceived=new char[50];
reader.read(bytesreceived , 0, 50);
text="";
for (int i=0;i<bytesreceived.length;i++)
{
text+=bytesreceived[i];
}
Toast.makeText(context, "Received2: "+text.trim(), 10000).show();
Log.d("IdealLog","Received2: "+text.trim());
} catch(Exception e) {
Log.e("TCP", "S: Error", e);
} finally {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
My server side code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace SocketServer
{
class Program
{
static void Main(string[] args)
{
IPEndPoint ip = new IPEndPoint(IPAddress.Any, 18001);
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socket.Bind(ip);
socket.Listen(10);
Console.WriteLine("Waiting for a client...");
Socket client = socket.Accept();
IPEndPoint clientep = (IPEndPoint)client.RemoteEndPoint;
Console.WriteLine("Connected with {0} at port {1}", clientep.Address, clientep.Port);
string welcome = "HELLO 1 FROM SERVER";
byte[] data = new byte[200];
int receiveddata=client.Receive(data);
Console.WriteLine("Received data from CLIENT1: {0}", System.Text.ASCIIEncoding.ASCII.GetString(data).Trim());
ASCIIEncoding asen = new ASCIIEncoding();
byte[] data2 = new byte[200];
data2 = asen.GetBytes(welcome);
int sentdata=client.Send(data2, data2.Length, SocketFlags.None);
Console.WriteLine("Sent data from SERVER: {0}", welcome);
byte[] data3 = new byte[200];
Console.WriteLine("Receiving data from CLIENT : {0}", "...");
client.Receive(data3);
Console.WriteLine("Received data from CLIENT2: {0}", System.Text.ASCIIEncoding.ASCII.GetString(data3).Trim());
byte[] data4 = new byte[200];
data4 = asen.GetBytes("HELLO 2 FROM SERVER");
sentdata = client.Send(data4, data4.Length, SocketFlags.None);
client.Close();
socket.Close();
Console.WriteLine("Disconnected from {0}", clientep.Address);
Console.ReadLine();
}
}
}
Now, everything is working fine, without hang. The only problem is, that i don't know if this will work for receiving , sending files.