I'm trying to create a proxy application, but I'm facing problems in server socket. The Server Socket is not accepting the connection and returning a socket. Hence, I cannot test the proxy application. What is wrong?
The problem line is indicated in WebServe.java:
public class WebServe implements Runnable {
Socket soc;
OutputStream os;
BufferedReader is;
String resource;
WebServe(Socket s) throws IOException {
soc = s;
os = soc.getOutputStream();
is = new BufferedReader(new InputStreamReader(soc.getInputStream()));
}
public void run() {
System.err.println("Running");
getRequest();
returnResponse();
close();
}
public static void main(String args[]) {
try {
System.out.println("Proxy Thread");
ServerSocket s = new ServerSocket(8080);
for (;;) {
s.setSoTimeout(10000);
WebServe w = new WebServe(s.accept()); // Problem is here
Thread thr = new Thread(w);
thr.start();
w.getRequest();
w.returnResponse();
w.close();
}
} catch (IOException i) {
System.err.println("IOException in Server");
}
}
void getRequest() {
System.out.println("Getting Request");
try {
String message;
while ((message = is.readLine()) != null) {
if (message.equals("")) {
break;
}
System.err.println(message);
StringTokenizer t = new StringTokenizer(message);
String token = t.nextToken();
if (token.equals("GET")) {
resource = t.nextToken();
}
}
} catch (IOException e) {
System.err.println("Error receiving Web request");
}
}
void returnResponse() {
int c;
try {
FileInputStream f = new FileInputStream("." + resource);
while ((c = f.read()) != -1) {
os.write(c);
}
f.close();
} catch (IOException e) {
System.err.println("IOException is reading in web");
}
}
public void close() {
try {
is.close();
os.close();
soc.close();
} catch (IOException e) {
System.err.println("IOException in closing connection");
}
}
}
public static void main(String args[]){
try {
System.out.println("Proxy Thread");
ServerSocket s = new ServerSocket (8080);
for (;;){
s.setSoTimeout(10000);
Move that ahead of the loop. You don't need to keep setting it. You don't really need it at all actually.
WebServe w = new WebServe (s.accept()); //Problem is here
The problem is here only because you set a socket timeout you don't actually need.
Thread thr = new Thread (w);
thr.start();
So far so good.
w.getRequest();
w.returnResponse();
w.close();
Remove. The next problem is here. The run() method of WebServ already does this.
As to the rest, you aren't writing an HTTP header in the response.
Related
I am using a data generator which uses ports for streaming data. I use multiple ports mfor receiving data. The software I am writing makes a new socket for each port. Every socket should make an instance of a class called 'Interpreter'.
The problem I have is the following: I am able to make multiple instances of Interpreter, but I think the data is all being parsed to only one of the instances. I think this happens because the data is 'merged' in the output.
This is the most important snipet of the code:
public class Main {
public static void main (String[] args) {
Socket socket;
ServerSocket serverSocket=null;
System.out.println("Server Listening..");
try{
serverSocket = new ServerSocket(7789);
}
catch(IOException e){
e.printStackTrace();
System.out.println("Error");
}
while(true){
try{
socket= serverSocket.accept();
Interpreter interp = new Interpreter();
ServerThread serverThr=new ServerThread(socket, interp);
serverThr.start();
}
catch(Exception e){
e.printStackTrace();
System.out.println("Connection Error");
}
}
}
}
class ServerThread extends Thread {
String line = null;
BufferedReader is = null;
PrintWriter os = null;
Socket s = null;
public ServerThread(Socket s, Interpreter interp) {
this.interp = interp;
this.s = s;
System.out.println("interp "+interp);
System.out.println("s: "+s);
System.out.println("poort: "+s.getPort());
}
public void run() {
try {
is = new BufferedReader(new InputStreamReader(s.getInputStream()));
os = new PrintWriter(s.getOutputStream());
} catch (IOException e) {
System.out.println("IO error in server thread");
}
try {
line = is.readLine();
while (line.compareTo("QUIT") != 0) {
os.println(line);
os.flush();
Interpreter.interpreter(line);
line = is.readLine();
}
} catch (IOException e) {
line = this.getName();
System.out.println("IO Error/ Client " + line + " terminated abruptly");
} catch (NullPointerException e) {
line = this.getName();
System.out.println("Client " + line + " Closed");
} finally {
try {
System.out.println("Connection Closing..");
if (is != null) {
is.close();
System.out.println(" Socket Input Stream Closed");
}
if (os != null) {
os.close();
System.out.println("Socket Out Closed");
}
if (s != null) {
s.close();
System.out.println("Socket Closed");
}
} catch (IOException ie) {
System.out.println("Socket Close Error");
}
}
}
}
This is the 'important' part of Interpreter:
public class Interpreter{
static AtomicInteger nextId = new AtomicInteger();
int id = nextId.incrementAndGet();
public Interpreter(){
System.out.println("ID of demo "+id);
}
}
I made a little game. Now i want to get the highscore from my Server. The code on the client:
private int getOnlineHighscore() {
int highscore = 0;
try {
socket = new Socket("localhost", 444);
input = socket.getInputStream();
System.out.println(input);
highscore = input.read();
input.close();
socket.close();
input = null;
socket = null;
} catch (Exception e) {
System.out.println("Verbindung fehlgeschlagen!");
}
System.out.println(highscore);
return highscore;
}
And on the Server:
import java.io.*;
import java.net.*;
public class ReadServer extends Thread {
private Socket socket;
public ReadServer(Socket socket) {
super();
this.socket = socket;
}
public void run() {
try {
System.out.println(socket.getInetAddress());
String result = "";
try (BufferedReader br = new BufferedReader(
new FileReader(System.getProperty("user.home") + "/AppData/Roaming/GameServer/.sg"))) {
StringBuilder sb = new StringBuilder();
String line = br.readLine();
System.out.println("2");
while (line != null) {
sb.append(line);
sb.append(System.lineSeparator());
line = br.readLine();
}
System.out.println("3");
result = sb.toString();
System.out.println("3.5");
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("4");
socket.getOutputStream().write(Integer.parseInt(result));
System.out.println(result);
} catch (Exception e) {
}
try {
socket.close();
} catch (Exception e) {
}
}
public static void main(String[] Args) {
Socket socket = null;
ServerSocket server = null;
try {
server = new ServerSocket(444);
while (true) {
socket = server.accept();
new ReadServer(socket).start();
}
} catch (Exception e) {
}
try {
server.close();
} catch (Exception e) {
}
}
}
If I run it, the client function returns:
-1
The server writes in the console(not important I think):
/127.0.0.1
2
3
3.5
4
How to solve the problem? I want to send an int stored on my Server to a client.
-Jakob
-1 is returned by read() to specify end of stream , make sure data to be read is being returned .
What is the highscore stored in the file? I believe the file is empty and it fails on parsing the integer but as your catch block is empty, you don't see the exception. Put printStacktrace or rethrow.
Another problem is that OutputStream sends only bytes and therefore write method sends only low 8 bits. To send int wrap the stream with DataOutputStream and DataInputStream on the client side.
Right now my server only can handle one client at a time. I am trying to use a Thread so that the server can handle several clients, but I am doing it wrong. I have added the thread in the try/catch clause where the serverSocket accepts the client, but this makes no difference. I don't get an error or anything, but it just doesn't work.
So what I want to do, is make the server not freeze at one client, but still accept several clients.
Here is the server code:
import java.io.*;
import java.net.*;
public class Server {
private BufferedReader reader;
private PrintWriter writer;
private int port;
public Server(int port)
{
this.port = port;
}
private String getSeverAddress() {
String host = null;
try {
InetAddress adr = InetAddress.getLocalHost();
host = adr.getHostAddress();
} catch (UnknownHostException e) {
e.printStackTrace();
}
return host;
}
public void startServer() {
print("Contact this sever on address: " + getSeverAddress() + " port: " + port);
ServerSocket ss = null;
Socket socket = null;
Thread clientThread = null;
try {
ss = new ServerSocket(port);
socket = ss.accept();
clientThread = new Thread(new Client(socket));
clientThread.start();
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
writer = new PrintWriter(socket.getOutputStream(), true);
String msg = null;
while (( msg = reader.readLine()) != null) {
print("System out: " + msg);
if(msg.equals("Bye")) {
print("Client left");
break;
}
}
ss.close();
socket.close();
reader.close();
writer.close();
} catch(SocketException e) {
e.printStackTrace();
} catch (IOException i ) {
i.printStackTrace();
return;
}
}
private void print(String msg) {
System.out.println(msg);
}
public static void main(String[] args) {
Server server = new Server(1111);
server.startServer();
}
}
Here is the client code:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
public class Client implements Runnable{
private Socket client;
private BufferedReader reader;
private PrintWriter writer;
public Client(Socket socket)
{
client = socket;
try{
reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
writer = new PrintWriter(client.getOutputStream(), true);
} catch (Exception e) {
e.printStackTrace();
return;
}
}
#Override
public void run() {
String msg = null;
BufferedReader r = null;
try {
r = new BufferedReader(new InputStreamReader(System.in));
} catch (Exception e1) {
e1.printStackTrace();
}
System.out.println("Write message to server");
while(true) {
try {
msg = r.readLine();
if(msg.equals("Quit") || msg == null) {
print("Disconnect");
break;
}
} catch (IOException e) {
e.printStackTrace();
}
writeToServer(msg);
}
try {
r.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public void writeToServer(String msg) {
writer.println(msg);
}
private void print(String msg) {
System.out.println(msg);
}
public static void main(String[] args) {
Socket socket = null;
try {
socket = new Socket("localhost", 1111);
} catch (Exception e) {
e.printStackTrace();
}
Client client = new Client(socket);
client.run();
}
}
You are still trying to handle clients in your main thread. Main thread should just accept new connections and start new threads. You also have to do accept in a loop so multiple connections can be accepted:
ss = new ServerSocket(port);
while(true) {
Socket socket = ss.accept();
Thread clientThread = new Thread(new Runnable() {
public void run() {
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter writer = new PrintWriter(socket.getOutputStream(), true);
String msg = null;
while (( msg = reader.readLine()) != null) {
print("System out: " + msg);
if(msg.equals("Bye")) {
print("Client left");
break;
}
}
socket.close();
reader.close();
writer.close();
}});
clientThread.start();
}
You need to put your ss.accept() into a while loop and create a new Thread for every client accepted, which handles the connection.
I am creating a remote-desktop screenshot application. I have two methods on the server 1) To read the Image from client 2) to read the list of task running on the client). But everytime I try to read the client's input stream an EOF excetion is thrown. The stakctrace of the exception is
java.io.EOFException at
java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2323)
at
java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2792)
at
java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:799)
at java.io.ObjectInputStream.(ObjectInputStream.java:299) at
remoteserverclient.original.ScreenServer$ServerThread.run(ScreenServer.java:254)
Here is the code on the server where the exception is thrown
ObjectInputStream in = new ObjectInputStream(client.getInputStream());
Object obj = in.readObject();
if (obj instanceof Rectangle) {
CaptureScreen(obj, in);
} else if (obj instanceof String) {
CaptureList(in);
}
Here is the complete code for the client
public class ScreenClient {
static Socket server;
public static void main(String[] args) throws Exception {
try {
while (true) {
server = new Socket("localhost", 5494);
BufferedReader bf = new BufferedReader(new InputStreamReader(server.getInputStream()));
String s;
s = bf.readLine();
System.out.println(s);
if (s.contains("execute")) {
new ClientMessageThread().start();
}
if (s.contains("getProcessList")) {
new ClientFetchProcessThread().start();
}
}
} catch (Exception e) {
System.err.println("Disconnected From server ->" + e.getMessage());
}
}
public static class ClientMessageThread extends Thread {
Socket server;
public ClientMessageThread() {
try {
server=new Socket("localhost",5494);
} catch (Exception ex) {
ex.printStackTrace();
}
}
#Override
public void run() {
try {
BufferedImage screen;
Robot robot = new Robot();
Rectangle size = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
screen = robot.createScreenCapture(size);
int[] rgbData = new int[(int) (size.getWidth() * size.getHeight())];
screen.getRGB(0, 0, (int) size.getWidth(), (int) size.getHeight(), rgbData, 0, (int) size.getWidth());
OutputStream baseOut = server.getOutputStream();
ObjectOutputStream out = new ObjectOutputStream(baseOut);
out.writeObject(size);
for (int x = 0; x < rgbData.length; x++) {
out.writeInt(rgbData[x]);
}
out.flush();
server.close();
//added new
} catch (Exception e) {
System.err.println("Disconnected From server ->" + e.getMessage());
}
}
}
public static class ClientFetchProcessThread extends Thread {
Socket server;
public ClientFetchProcessThread() {
try {
server=new Socket("localhost",5494);
} catch (Exception ex) {
ex.printStackTrace();
}
}
public void run() {
try {
PrintWriter ps;
System.out.println("\n\n********");
StringBuilder builder = new StringBuilder("");
String query = "tasklist";
Runtime runtime = Runtime.getRuntime();
InputStream input = runtime.exec(query).getInputStream();
BufferedInputStream buffer = new BufferedInputStream(input);
BufferedReader commandResult = new BufferedReader(new InputStreamReader(buffer));
String line = "";
ps = new PrintWriter(server.getOutputStream(), true);
while ((line = commandResult.readLine()) != null) {
builder.append(line + "\n");
//byte[] responseClient=s.getBytes();
ps.write(builder.toString());
System.out.println(builder.toString());
}
server.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
You're both printing and writing objects to port 5494 from the client. The server only reads objects.
Sort it out.
The exception being thrown is EOFException (End of file exception).
ObjectInputStream throws EOFException when it reaches the end of the input. That's standard behaviour. Are you catching all exceptions thrown by in.readObject()?
Documentation:
http://docs.oracle.com/javase/7/docs/api/java/io/ObjectInputStream.html
I'm developing an asynchronous socket client based on threads. When the program calls readLine(), it blocks indefinitely and never returns.
public class ADNClient {
Socket socket = null;
DataOutputStream dataOutputStream = null;
DataInputStream dataInputStream = null;
Thread listener = new Thread(new Runnable() {
#Override
public void run() {
String line;
try {
// Stop here and doesn't progress
while ((line = dataInputStream.readLine()) != null) {
//DO something
}
}
catch (IOException e) {}
});
public ADNClient() {
try {
socket = new Socket("192.168.1.5", 5000);
dataOutputStream = new DataOutputStream(socket.getOutputStream());
dataInputStream = new DataInputStream(socket.getInputStream());
listener.start();
//sender.start();
} catch (Exception e) {
Log.e("ADN", e.getMessage());
}
}
public void close() {
listener.stop();
try {
socket.close();
} catch (IOException e) {
Log.e("ADN", e.getMessage());
}
}
}
Ok... I'm noob with IN/Outputstreams... I didn't send the newline character, the correct way to recive information is using
readUTF()
instead of
readLine()
Thank you Greg Kopff!