I need to implement a program to transfer files. I decided to make it using a chat template I've made about 1 month ago so I would have a chat with file transfer option. The transfer should follow the following points:
1- Server only keeps a list of all files provided by connected clients (No file are actually located in the server, only their names)
2- Client "1" requests file "A" then:
if file "A" is located ONLY in client "2", then client "2" should send 100% of the file to client "1"
if file "A" is located in client "2" and client "3" also has file "A", then client "2" should send 50% of the file to client "1" and client "3" should send the other 50%.
(if the file is located in 4 clients it should be 25% each....and so it goes...)
I've already managed to make the server find out which client is requesting the file and which clients have it. But now I'm stuck, I don't know how to make the transfer.
Could someone give me an example of how to do it? or point me through the right direction?
[I'm aware my code has some flaws and I will fix it later, right now I need to make the transfer happen before working on fixes, so please, unless it's related, try to focus on that]
Server:
package tor;
import java.util.*;
import java.io.*;
import java.net.*;
public class Server extends Thread {
private String cname;
private Socket client;
public static Vector<PrintStream> clients;
public static Vector<String> clientnames;
public static Vector<String> archives;
public Server(Socket client) {
this.client = client;
}
public static void main(String[] args) {
clients = new Vector<PrintStream>();
clientnames = new Vector<String>();
archives = new Vector<String>();
try {
ServerSocket server = new ServerSocket(2391);
System.out.println("Server Started!!\n");
while (true) {
Socket client = server.accept();
Server s = new Server(client);
s.start();
}
} catch (IOException e) {
System.out.println("Server could not start ");
}
}
@Override
public void run() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
PrintStream out = new PrintStream(client.getOutputStream());
cname = in.readLine();
System.out.println(cname + " Connected --- SERVER!");
if (cname == null) {
System.out.println("Unknown Name");
return;
}
clientnames.add(cname);
clients.add(out);
connected(" ********** [", cname, "] Connected! **********");
String arq;
int size = in.read();
System.out.println(size);
for (int i = 0; i < size; i++) {
arq = in.readLine();
archives.add(arq);
}
String msg = in.readLine();
String selected;
while (true) {
while (!(msg).equals("/exit") && !(msg).equals("/Exit") && !(msg).equals("/EXIT")) {
if ((msg).equals("/list") || (msg).equals("/List") || (msg).equals("/list")) {
out.println("-------- Archives List --------");
for (int i = 0; i < archives.size(); i++) {
out.println(i+"- "+archives.get(i));
}
out.println("-------- ******************* --------");
msg = in.readLine();
} else if (msg.equals("/get") || (msg.equals("/GET")) || (msg.equals("/Get"))){
msg = in.readLine();
int gnum = Integer.parseInt(msg);
selected=archives.get(gnum);
returnAll("[", out, "]: ", "idreq");
out.println("1");
reqAll(selected);
// I BELIVE HERE IS THE RIGHT PLACE TO MAKE DE TRANSFER CODE
msg = in.readLine();
} else {
returnAll("[", out, "]: ", msg);
msg = in.readLine();
}
}
msg = in.readLine();
size = Integer.parseInt(msg);
for (int i = 0; i <= size; i++) {
arq = in.readLine();
for(int j=0;j<archives.size();j++) {
if (archives.get(j).equals(arq)) {
archives.remove(j);
}
}
}
returnAll(" ********** [", out, "] disconnected ", " ********** ");
clients.remove(out);
clientnames.remove(cname);
client.close();
break;
}
} catch (IOException e) {
System.out.println("A Client disconnected ");
}
}
// METHOD TO SEND CONNECTION MESSAGE
public void connected(String msg1, String cname, String msg2) throws IOException {
Enumeration<PrintStream> e = clients.elements();
while (e.hasMoreElements()) {
PrintStream message = (PrintStream) e.nextElement();
message.println(msg1 + cname + msg2);
}
}
// METHOD TO RETURN MESSAGE TO ALL CLIENTS
public void returnAll(String msg1, PrintStream saida, String ac, String msg2) throws IOException {
Enumeration<PrintStream> e = clients.elements();
while (e.hasMoreElements()) {
PrintStream message = (PrintStream) e.nextElement();
message.println(msg1 + cname + ac + msg2);
}
}
public void reqAll(String req) throws IOException {
Enumeration<PrintStream> e = clients.elements();
while (e.hasMoreElements()) {
PrintStream message = (PrintStream) e.nextElement();
message.println(req);
}
}
}
Client:
package tor;
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.Scanner;
public class Client extends Thread {
private Socket con;
private static boolean done = false;
static ArrayList<String> localArq = new ArrayList<String>();
static int c=0;
public Client(Socket s) {
con = s;
}
public static void main(String[] args) {
try {
String ip;
Scanner s = new Scanner(System.in);
System.out.print("Enter Server's IP: ");
ip =s.next();
Socket con = new Socket(ip, 2391);
PrintStream out = new PrintStream(con.getOutputStream());
System.out.println("Connected to Server!");
System.out.print("Enter your Nickname: ");
BufferedReader scan = new BufferedReader(new InputStreamReader(System.in));
String cname = scan.readLine();
out.println(cname);
String dir="C:\\javator\\"+cname;
Thread t = new Client(con);
t.start();
File folder = new File(dir);
folder.mkdir();
File[] listOfFiles = folder.listFiles();
for (int i = 0; i < listOfFiles.length; i++) {
if (listOfFiles[i].isFile()) {
localArq.add(listOfFiles[i].getName());
}
}
int size=localArq.size();
out.write(size);
for(int i=0;i<size;i++) {
out.println(localArq.get(i));
}
String msg;
while (true) {
System.out.print("");
msg = scan.readLine();
if(msg.equals("/ll")) {
System.out.println("-------- LOCAL LIST --------");
for (int i = 0; i < localArq.size(); i++) {
System.out.println(localArq.get(i));
}
System.out.println("-------- ******************* --------");
msg = scan.readLine();
}else if(msg.equals("/exit") || (msg.equals("/Exit")) || (msg.equals("/EXIT"))) {
out.println(msg);
size=localArq.size();
out.println(size);
for(int i=0;i<size;i++) {
out.println(localArq.get(i));
}
}
else if(msg.equals("/get") || (msg.equals("/GET")) || (msg.equals("/Get"))) {
System.out.println("Chose file's number to /get: ");
c++;
}
if (done == true) {
break;
}
out.println(msg);
}
} catch (UnknownHostException e) {
System.out.println(e.getMessage());
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
@Override
public void run() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
String rmsg;
String req;
while (true) {
rmsg = in.readLine();
if (rmsg == null) {
System.out.println("Connection Terminated");
break;
}else if(rmsg.substring(rmsg.length() - 5).equals("idreq")) {
req = in.readLine();
for(int i=0;i<localArq.size();i++) { //IDENTIFIES WHO OWNS THE REQUESTED FILE
if(localArq.get(i).equals(req)) {
System.out.println("Owns requested file");
Socket requester = new Socket("192.168.3.114", 2007);
ObjectOutputStream outputr = new ObjectOutputStream(requester.getOutputStream());
ObjectInputStream inputr = new ObjectInputStream(requester.getInputStream());
Object mens= inputr.readObject();
System.out.println(mens);
outputr.writeObject("OWNER FOUND");
}
}
if(c==1) { //IDENTIFIES WHO WANTS THE FILE
rmsg = in.readLine();
c= Integer.parseInt(rmsg);
System.out.println("file: "+req);
ServerSocket peer = new ServerSocket(2007);
System.out.println("OPEN FOR CONNECTIONS\n");
Socket client = peer.accept();
System.out.println("Client connected: " + client.getInetAddress().getHostAddress());
ObjectOutputStream outputo = new ObjectOutputStream(client.getOutputStream());
ObjectInputStream inputo = new ObjectInputStream(client.getInputStream());
outputo.flush();
outputo.writeObject("Connected to requester");
Object mens= inputo.readObject();
System.out.println(mens);
}
}
else {
System.out.println(rmsg);
}
}
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
done = true;
}
}
I was able to make a transfer between two clients easily with the information provided and a little research on stackOverflow to understand more about out/inputStreams! This post also helped me a lot: Sending a file with Java Sockets, losing data next step is the shared transfer