I am trying to create an Android Server and Client on C# base on TCP Socket. I want them both to send and received a string(Data) so I can make a command base on the given string(Data). For the meantime, the Server can listen to incoming clients and the Clients can connect to Server. But I have two problem and i can't solve it.
PROBLEMS:
1. When i try to send the data to Server, the Server was unable to Read it.
2. When the Client is Disconnected, the Server is giving me a loop of Null.
I already try to Search about communicating C# and Android using TCP but i didn't found anything like what i need.
The following code is for Android Server.
I am having a loop of Null in class CommunicationThread when the client is Disconnected. I think it's because I am using a while for reading the Data from client, but since it become disconnected then it is resulting a null.
public class MainActivity extends AppCompatActivity {
TextView tx1, tx_waiting;
private ServerSocket serverSocket;
Handler updateConversationHandler, dg;
Thread serverThread = null;
public static final int SERVERPORT = 6000;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tx1 = (TextView)findViewById(R.id.textView1);
tx_waiting = (TextView)findViewById(R.id.tx_waiting);
//Start the Server
try{
updateConversationHandler = new Handler();
dg = new Handler();
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
tx_waiting.setVisibility(View.VISIBLE);
Log.d("Server Starting","Server Already Started.");
}catch (Exception e){
e.printStackTrace();
}
}
#Override
protected void onStop() {
super.onStop();
try {
serverSocket.close();
Log.d("Server Stop","Successfully Stopped the Server Without any Error.");
} catch (IOException e) {
Log.e("Server Failed to Stop",e.toString());
}
}
class ServerThread implements Runnable {
public void run() {
Socket socket = null;
try {
serverSocket = new ServerSocket(SERVERPORT);
Log.d("Server Thread","Server Thread Already Started.");
} catch (IOException e) {
e.printStackTrace();
}
while (!Thread.currentThread().isInterrupted()) {
try {
socket = serverSocket.accept();
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
Log.d("Server Socket","New Client is Connected");
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class CommunicationThread implements Runnable {
private Socket clientSocket;
private BufferedReader input;
public CommunicationThread(Socket clientSocket) {
this.clientSocket = clientSocket;
try {
this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
Log.d("Input Stream","Input Stream Received!.");
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
while (!Thread.currentThread().isInterrupted()) {
try {
String read = input.readLine();
updateConversationHandler.post(new updateUIThread(read));
Log.d("Update Convers.","Conversation was Updating...");
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class updateUIThread implements Runnable {
private String msg;
public updateUIThread(String str) {
this.msg = str;
}
#Override
public void run() {
Log.d("Client Data",msg.toString());
}
}
}
The following code is for C# Client to Connect and Send the Data.
System.Net.Sockets.TcpClient clientSocket = new System.Net.Sockets.TcpClient();
NetworkStream serverStream = default(NetworkStream);
Task f = Task.Factory.StartNew(() => {
//Connect the Client into Server
try {
clientSocket.Connect(tb_ip.Text, int.Parse(tb_port.Text));
}
catch (Exception ezz) {
MessageBox.Show("Server Not Found.");
}
//Assuming that the CLient is Connected then Send a Sample Data
try {
serverStream = clientSocket.GetStream();
byte[] outStream = System.Text.Encoding.ASCII.GetBytes("This is Sample Data");
serverStream.Write(outStream, 0, outStream.Length);
serverStream.Flush();
}
catch (Exception er) {
Console.WriteLine(er.ToString());
}
});
I have no method yet for Sending the Data from Server to Client since I am just starting to make this thing works, But if you have anything that can help me about this then i will really appreciate it. Thanks.
Related
I am writing a program to eventually make my own file server. I am having issues with connecting to the server in a web browser via typing myIpAddress:port into the browser while the server is running. This does work if I use one computer to both host the server and be a client, but does not if I use a second computer to be a client.
I have 2 classes, Index and ClientHandler
public class Index {
public static void main(String[] args) {
ServerSocket server = null;
try {
server = new ServerSocket(8080);
DevInterface myFace = new DevInterface(server);
System.out.println("Listening for connection on port 8080");
} catch (IOException e) {
e.printStackTrace();
}
int i = 0;
while(true) {
Socket client = null;
try {
client = server.accept();
ClientHandler clientHandler = new ClientHandler(client);
clientHandler.start();
System.out.println("got a client");
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
and my ClientHandler class which is what sends my html to the server is this.
public class ClientHandler extends Thread{
private Socket client = null;
private PrintWriter out = null;
ArrayList<Socket> clientList = null;
public ClientHandler(Socket client) {
this.client = client;
}
public ClientHandler(Socket client, ArrayList<Socket> clientList) {
this.client = client;
this.clientList = clientList;
}
public void run() {
try {
out = new PrintWriter(client.getOutputStream());
out.println("HTTP/1.1 200 OK");
out.println("Content-Type: text/html");
out.println("\r\n");
out.println("<p>Hello World</p>");
out.flush();
out.close();
if(client!=null) {client.close();}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
I'm trying to make a client/server application using an Android phone as a client using AsyncTask to send messages from UI.
I've written some very basic implementation just to test the connection and the way that messages are received / sent and I found a very big problem.
The client part seems to work fine..from my perspective. But the server part is the problem. I can't make the server reading and displaying messages countinously from the client.
I tried something like while(line = (in.readLine()) != null) {} but it doesn't seems to work.
After I sent my first word from the client, the server reads null and it stops.
Can someone show me a proper way to keep the server running while the client is not sending nothing?
I'd like to avoid using while(true) if it's not 100% necessary.
Here is the implementation until now:
Server:
public class SocketServerThread extends Thread {
private static final Logger log = Logger.getLogger(SocketServerThread.class);
private static final int SERVER_PORT_NUMBER = 5000;
#Override
public void run() {
try {
ServerSocket serverSocket = new ServerSocket(SERVER_PORT_NUMBER);
serverSocket.setReuseAddress(true);
log.info("Waiting for connection...");
Socket clientSocket = serverSocket.accept();
log.info("Connected! Receiving message...");
BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
try {
while (true) {
String line = in.readLine();
if (line != null) {
log.info(line);
}
}
} catch (Exception e) {
log.error("Unexpected exception while sending / receiving messages.");
e.printStackTrace();
} finally {
in.close();
clientSocket.close();
serverSocket.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
Client:
public class MyAsyncTask extends AsyncTask<String, Integer, String> {
private static final String TAG = "MyAsyncTask";
private static final String SERVER_IP_ADDRESS = "10.0.2.2";
private static final int SERVER_PORT_NUMBER = 5000;
private PrintWriter out;
#Override
protected String doInBackground(String... params) {
String message = "";
try {
InetAddress address = InetAddress.getByName(SERVER_IP_ADDRESS);
Log.d(TAG, "Connecting...");
Socket socket = new Socket(address, SERVER_PORT_NUMBER);
try {
out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
Log.d(TAG, "I/O created");
message = params[0];
if (!message.equals("stop")) {
sendMessage(message);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
out.flush();
out.close();
socket.close();
}
} catch (Exception e) {
e.printStackTrace();
}
return message;
}
private void sendMessage(String message) {
if (out != null && !out.checkError()) {
out.println(message);
out.flush();
Log.d(TAG, "Sent message: " + message);
}
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
Log.d(TAG, "onPostExecute(), s: " + s);
}
Thank you.
The problem is that your BufferedReader only read the first input stream. In order to receive the text after that, you have to re-read the input stream. I do it by recreating the socket when I am done reading, so that I can read next coming data. I am using the following code in my app. You can use this
private ServerSocket serverSocket;
public static final int SERVERPORT = 5000;
Thread serverThread = null;
public void startSocketServer(){
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
}
public void stopSocket(){
if(serverSocket != null){
try{
serverSocket.close();
}
catch (IOException e){
e.printStackTrace();
}
}
}
class ServerThread implements Runnable {
public void run() {
Socket socket = null;
try {
Log.wtf(TAG,"Socket: New Socket");
serverSocket = new ServerSocket(SERVERPORT);
if(serverSocket == null){
runOnUiThread(new Runnable() {
#Override
public void run() {
startSocketServer();
}
});
return;
}
while (!Thread.currentThread().isInterrupted() && !serverSocket.isClosed()) {
try {
socket = serverSocket.accept();
Log.wtf(TAG,"Socket: Accepting");
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
} catch (IOException e) {
Log.wtf(TAG,"Socket: Error");
e.printStackTrace();
}
if(Thread.currentThread().isInterrupted()){
Log.wtf(TAG, "Thread Interrupted");
}
if(serverSocket.isClosed()){
Log.wtf(TAG, "serverSocket closed");
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
class CommunicationThread implements Runnable {
private Socket clientSocket;
public CommunicationThread(Socket clientSocket) {
this.clientSocket = clientSocket;
log.info("Connected! Receiving message...");
try {
BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
try {
while (true) {
String line = in.readLine();
if (line != null) {
log.info(line);
}
else
break;//This will exit the loop and refresh the socket for next data
}
} catch (Exception e) {
log.error("Unexpected exception while sending / receiving messages.");
e.printStackTrace();
}
finally {
in.close();
clientSocket.close();
}
refreshSocket();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void refreshSocket(){
runOnUiThread(new Runnable() {
#Override
public void run() {
stopSocket();
startSocketServer();
}
});
}
Just call startSocketServer() to start the server socket in your code.
How do you make a client which is able to send a server multiple messages at anytime, and therefore a server listening for a message all the time.
Right now I have wrote some code which only allows me to send a message once. I thought this was due to me closing the input/output streams and the sockets. So I have been playing around for a while now and I can't seem to do it!
Client:
public class Client {
private Socket socket;
private OutputStream os;
public Client() {}
public void connectToServer(String host, int port) {
try {
socket = new Socket(host, port);
} catch (IOException e) {
e.printStackTrace();
}
sendMessage();
}
public void sendMessage() {
try {
os = socket.getOutputStream();
String string = "Anthony";
byte[] b = string.getBytes(Charset.forName("UTF-8"));
os.write(b);
os.flush();
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public void STOP() {
stopOutput();
stopServer();
}
public void stopServer() {
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public void stopOutput() {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Server:
public class ConnectionHandler implements Runnable {
private Socket clientSocket;
private BufferedReader in;
public ConnectionHandler(Socket clientSocket) {
this.clientSocket = clientSocket;
String clientAddress = clientSocket.getInetAddress().toString()
.substring(1);
System.out.println("Connected to " + clientAddress);
try {
in = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public void run() {
while (true) {
try {
ArrayList<String> data = new ArrayList<String>();
String inputLine;
while ((inputLine = in.readLine()) != null) {
data.add(inputLine);
}
if (data.size() > 0) {
System.out.println(data.toString());
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void STOP() {
stopInput();
stopConnection();
}
public void stopInput() {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public void stopConnection() {
try {
clientSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
At the moment on the client side, I send a message as soon as the socket is opened but after when I call the send function from another class it does not send...
How should I do this? Or what am I doing wrong?
Thanks in advance.
p.s. I am guessing client-server is the same as server-client, so if I know how to do one way I can easily switch it around... right?
Turns outs it was a simple error.
I as writing (sending-client) as an OutputStream however I was then reading (receiving-server) as BufferedReader! ha
So quick tip for anyone, make sure you receive messages the same way you send them!
Thanks for everyone who tried helping.
Your server is accepting data all the time, so you just have to save the OutputStream of you Client somewhere and write data to it every now and then. But do not close it, because then you close the Client socket, too.
After you have done that, you would need to change something else, because now your call of in.readLine() blocks your server, because it waits for the client to send something. To prevent that, you could try to add sending a String like "close" to the server when you want to close your client, something like that:
public void STOP() {
os.write("close".getBytes(Charset.forName("UTF-8")));
stopOutput();
stopServer();
}
and change the code in your server to
try {
ArrayList<String> data = new ArrayList<String>();
String inputLine;
while (!(inputLine = in.readLine()).equals("close")) {
data.add(inputLine);
}
if (data.size() > 0) {
System.out.println(data.toString());
}
} catch (IOException e) {
e.printStackTrace();
}
So, i have a Android-App(Client) and a Java-program(Server), with a One-time socket communication, whenever the android app connects to my server in a special activity (working fine).
Because my server is embedded in a bigger program (with Swing-components, where the server takes its informations from), i have this (reduced) code here:
//somewhere in my Swing-Application
Server myServer = new Server();
myServer.start();
//...
public class Server extends Thread {
#Override
public void run() {
try {
ServerSocket serverSocket = new ServerSocket(8090);
try {
while (true) {
System.out.println("Server is waiting for connections...");
socket = serverSocket.accept();
startHandler(socket);
}
} finally {
serverSocket.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
private void startHandler(final Socket socket) throws IOException {
System.out.println("Client connected to Server");
Thread thread = new Thread() {
#Override
public void run() {
try {
writer = new OutputStreamWriter(socket.getOutputStream(), "UTF-8");
//doing something usefull, i am sending a JSON-String, which i´ll parse in my app.
writer.write(someStringContainingJSONString);
writer.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
closeSocket();
}
}
private void closeSocket() {
try {
socket.close();
} catch (IOException e) {
}
}
};
thread.start();
}
In my Android-App i have:
public void onCreate(Bundle savedInstanceState) {
viewJSON = new Runnable() {
#Override
public void run() {
getJSON();
}
};
Thread thread = new Thread(null, viewJSON, "MagentoBackground");
thread.start();
myProgressDialog = ProgressDialog.show(myActivity.this, "Please wait...", "Retrieving data ...", true);
}
private void getJSON() {
try {
socket = new Socket(serverIPAddress, SERVER_PORT);
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));
String help = reader.readLine();
// parse this String according to JSON, is working fine!
}
// catch and so on...
Now, i want the app, to recieve data, whenever i hit a button "send data" from my Swing-Application, to have the newest data available.
On the other hand, i want the server to recieve data (also a JSON-String) when i make changes in my Android app. The String should also be send when i hit a specific button.
How can i do that? The problem is the threading issue(otherwise my swing application wouldn´t work) combined with networking. If i don´t close the socket, i cannot continue with my program properly (or at least, it seems so with my code right now)
Can you help me out here?
Thank you very much in advance for your help and thoughts.
Best, Andrea
I'm having a problem with a little game I'm designing in my class.
The problem is that I got two clients connected to a server. (client1 and client2) They are each running a game, which in the end, closes the window. As the game window is a JDialog, it will then, when it's closed, send a message, through a socket, to the server, telling it that it's done. I want the server to know which of the two clients were completed first. They are reporting through a PrintWriter on the sockets' OutputStream.
What I did was this:
in1 = new BufferedReader(new InputStreamReader(client.getInputStream()));
in2 = new BufferedReader(new InputStreamReader(client2.getInputStream()));
try {
in1.readLine();
} catch (IOException ex) {
Logger.getLogger(gameServer.class.getName()).log(Level.SEVERE, null, ex);
}
try {
in2.readLine();
} catch (IOException ex) {
Logger.getLogger(gameServer.class.getName()).log(Level.SEVERE, null, ex);
}
Problem is that it waits for the first input, before it even starts listening on the second. How can I make it listen on both at the same time? Or solve my problem some other way.
Thanks!
Server connection should work like this:
Server gameServer = new Server();
ServerSocket server;
try {
server = new ServerSocket(10100);
// .. server setting should be done here
} catch (IOException e) {
System.out.println("Could not start server!");
return ;
}
while (true) {
Socket client = null;
try {
client = server.accept();
gameServer.handleConnection(client);
} catch (IOException e) {
e.printStackTrace();
}
}
In hanleConnection() you start a new thread and run the communication for this client in the created thread. Then the server can accept a new connection (in the old thread).
public class Server {
private ExecutorService executor = Executors.newCachedThreadPool();
public void handleConnection(Socket client) throws IOException {
PlayerConnection newPlayer = new PlayerConnection(this, client);
this.executor.execute(newPlayer);
}
// add methods to handle requests from PlayerConnection
}
The PlayerConnection class:
public class PlayerConnection implements Runnable {
private Server parent;
private Socket socket;
private DataOutputStream out;
private DataInputStream in;
protected PlayerConnection(Server parent, Socket socket) throws IOException {
try {
socket.setSoTimeout(0);
socket.setKeepAlive(true);
} catch (SocketException e) {}
this.parent = parent;
this.socket = socket;
this.out = new DataOutputStream(socket.getOutputStream());;
this.in = new DataInputStream(socket.getInputStream());
}
#Override
public void run() {
while(!this.socket.isClosed()) {
try {
int nextEvent = this.in.readInt();
switch (nextEvent) {
// handle event and inform Server
}
} catch (IOException e) {}
}
try {
this.closeConnection();
} catch (IOException e) {}
}
}