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Completed Network File-Sharing Chat System backend and client logic

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This commit is contained in:
Fatemesadat Mirabootalebi
2026-06-19 13:42:25 -07:00
parent 240eac0504
commit 11d776da15
5 changed files with 229 additions and 7 deletions
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.idea/misc.xml
Generated
+1 -1
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@@ -8,7 +8,7 @@
</list>
</option>
</component>
<component name="ProjectRootManager" version="2" project-jdk-name="25" project-jdk-type="JavaSDK">
<component name="ProjectRootManager" version="2" languageLevel="JDK_25" default="true" project-jdk-name="loom-ea-25" project-jdk-type="JavaSDK">
<output url="file://$PROJECT_DIR$/out" />
</component>
</project>
src/main/java/com/university/chat/Client/ServerListener.java
+15
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@@ -1,9 +1,16 @@
package com.university.chat.Client;
import com.university.chat.Common.ChatMessage;
import com.university.chat.Common.FileMessage;
import java.io.ObjectInputStream;
public class ServerListener implements Runnable{
// TODO: store the ObjectInputStream from the user socket
// (this should be the same input stream the
// chatClient created when connecting)
private final ObjectInputStream in;
public ServerListener(ObjectInputStream in){
this.in = in;
}
@Override
public void run() {
@@ -13,6 +20,14 @@ public class ServerListener implements Runnable{
// - if it's a FileMessage -> print that a file was received
// (filename + sender), it's already
// saved to disk by the server.
while (true) {
Object received = in.readObject();
if (received instanceof ChatMessage chatMsg){
System.out.println("\n" + chatMsg.getSender() + ": " + chatMsg.getContent());
}
else if (received instanceof FileMessage fileMsg){
System.out.println("\n[FILE RECEIVED] '" + fileMsg.getFilename() + "' sent by " + fileMsg.getSender() + ". Saved at server.");
}}
} catch (Exception e){
System.out.println("Disconnected from server");
}
src/main/java/com/university/chat/Client/chatClient.java
+102 -5
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@@ -1,29 +1,126 @@
package com.university.chat.Client;
import com.university.chat.Common.ChatMessage;
import com.university.chat.Common.FileMessage;
import com.university.chat.Common.MessageType;
import java.io.*;
import java.net.Socket;
import java.util.Scanner;
public class chatClient {
public static void main() {
private static final String DEFAULT_HOST = "localhost";
private static final int DEFAULT_PORT = 8585;
public static void main(String[] args) {
// TODO: Connecting to the server
// 1. Create a socket and connect to the server
Scanner scanner = new Scanner(System.in);
System.out.print("Enter username: ");
String username = scanner.nextLine().trim();
try {
Socket socket = new Socket(DEFAULT_HOST, DEFAULT_PORT);
// 2. Create an ObjectOutputStream (out) and ObjectInputStream (in)
// from the socket's streams — output FIRST, then input.
ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
out.flush();
ObjectInputStream in = new ObjectInputStream(socket.getInputStream());
// 2. Get the username, and send a LOGIN ChatMessage with that username
// 3. Start a new Thread running a ServerListener(in) so incoming
// messages are handled concurrently.
out.writeObject(new ChatMessage(MessageType.LOGIN, username, "SERVER", ""));
out.flush();
Object response = in.readObject();
if (response instanceof ChatMessage serverMsg){
if (serverMsg.getType() == MessageType.LOGIN_FAILED){
System.out.println("Login failed: " + serverMsg.getContent());
socket.close();
scanner.close();
return;
}
else if (serverMsg.getType() == MessageType.LOGIN_SUCCESS){
System.out.println("Login successful! " + serverMsg.getContent());
System.out.println("Commands: /msg <user> <text>, /users, /sendfile <user> <path>, or just type text for public chat.");
}
}
// 3. Start a new Thread running a ServerListener(in) so incoming
// messages are handled concurrently.
ServerListener listener = new ServerListener(in);
Thread listenerThread = new Thread(listener);
listenerThread.start();
while (true){
try {
// TODO: Program loop — read a line from the console and act on it:
String line = scanner.nextLine().trim();
if (line.isEmpty()) continue;
if (line.startsWith("/msg ")){
// - "/msg <user> <text>" -> build & send a PRIVATE_MESSAGE
String[] parts = line.split(" ", 3);
if (parts.length >= 3){
String targetUser = parts[1];
String text = parts[2];
out.writeObject(new ChatMessage(MessageType.PRIVATE_MESSAGE, username, targetUser, text));
out.flush();
}
else{
System.out.println("Usage: /msg <user> <text>");
}
}
else if (line.equals("/users")){
// - "/users" -> build & send a USER_LIST request
out.writeObject(new ChatMessage(MessageType.USER_LIST, username, "SERVER", ""));
out.flush();
}
else if (line.startsWith("/sendfile ")){
// - "/sendfile <user> <path>" -> read the file into a byte[]
// (you can use TransferProgress
// to show progress)
// and send it as a FileMessage
// - anything else -> send a PUBLIC_MESSAGE
String[] parts = line.split(" ", 3);
if (parts.length >= 3){
String targetUser = parts[1];
String filePath = parts[2];
File file = new File(filePath);
if (!file.exists() || !file.isFile()){
System.out.println("File does not exist or is not a valid file.");
continue;
}
long fileSize = file.length();
byte[] fileData = new byte[(int) fileSize];
// Reading file while simulating the TransferProgress bar
try (FileInputStream fis = new FileInputStream(file)){
TransferProgress progress = new TransferProgress(fileSize);
int bytesRead;
int totalBytesRead = 0;
byte[] buffer = new byte[4096];
while ((bytesRead = fis.read(buffer)) != -1){
System.arraycopy(buffer, 0, fileData, totalBytesRead, bytesRead);
totalBytesRead += bytesRead;
progress.update(totalBytesRead);
}
}
FileMessage fileMsg = new FileMessage(username, targetUser, file.getName(), fileData);
out.writeObject(fileMsg);
out.flush();
System.out.println("File sent to server successfully.");
}
else{
System.out.println("Usage: /sendfile <user> <path>");
}
}
else{
// - anything else -> send a PUBLIC_MESSAGE
out.writeObject(new ChatMessage(MessageType.PUBLIC_MESSAGE, username, "ALL", line));
out.flush();
}
// Remember to flush() the output stream after writeObject().
} catch (Exception e){
}
catch (Exception e){
System.out.println("command failed: " + e.getMessage());
}
}
}
}
catch (Exception e){
System.out.println("Client Error: " + e.getMessage());
}
}}
src/main/java/com/university/chat/Server/ChatServer.java
+18
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@@ -1,15 +1,33 @@
package com.university.chat.Server;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
public class ChatServer {
// TODO: declare a single shared UserManager instance (static final)
// This MUST be shared by all ClientSession threads so that
// broadcasting and private messaging work correctly.
public static final UserManager userManager = new UserManager();
private static final int PORT = 8585;
public static void main(String[] args) {
// TODO: Create a ServerSocket
try (ServerSocket serverSocket = new ServerSocket(PORT)) {
System.out.println("Chat Server started on port " + PORT);
// TODO: In an infinite loop:
// accept an incoming client connection
// make a new thread running ClientSession for each user.
while (true){
Socket clientSocket = serverSocket.accept();
System.out.println("New client connecting: " + clientSocket.getRemoteSocketAddress());
ClientSession session = new ClientSession(clientSocket, userManager);
Thread sessionThread = new Thread(session);
sessionThread.start();
}
}
catch (IOException ex){
System.err.println("Server exception: " + ex.getMessage());
}
}
}
src/main/java/com/university/chat/Server/ClientSession.java
+93 -1
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@@ -2,44 +2,96 @@ package com.university.chat.Server;
import com.university.chat.Common.ChatMessage;
import com.university.chat.Common.FileMessage;
import com.university.chat.Common.MessageType;
import java.io.IOException;
import java.net.Socket;
import java.nio.file.Files;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;
public class ClientSession implements Runnable {
private String username;
private final Socket socket;
private final UserManager userManager;
private ObjectOutputStream out;
private ObjectInputStream in;
public ClientSession(Socket socket, UserManager userManager) {
this.socket = socket;
this.userManager = userManager;
// TODO : Create an ObjectOutputStream from socket.getOutputStream()
// and an ObjectInputStream from socket.getInputStream().
}
try {// Output FIRST, then Input to avoid handshake deadlock
this.out = new ObjectOutputStream(socket.getOutputStream());
this.out.flush();
this.in = new ObjectInputStream(socket.getInputStream());
}
catch (IOException ex){
System.err.println("Error setting up streams for session: " + ex.getMessage());
closeResources();
} }
@Override
public void run() {
if (in == null || out == null) return;
try {
// TODO: Welcome the user (login step)
// 1. Read the first object sent by the client.
Object firstObject = in.readObject();
// 2. Check it's a ChatMessage with type LOGIN.
// 3. Extract the username.
if (firstObject instanceof ChatMessage msg && msg.getType() == MessageType.LOGIN) {
this.username = msg.getSender();
// 4. Try to register the user via userManager.addUser(...).
// 5. If the username is taken, send back LOGIN_FAILED and close the socket.
// 6. Otherwise, create the user's folders with FileManager.createUserFolders(...)
// and send back LOGIN_SUCCESS.
if (username != null && !username.trim().isEmpty() && userManager.addUser(username, this)){
FileManager.createUserFolders(username);
out.writeObject(new ChatMessage(MessageType.LOGIN_SUCCESS, "SERVER", username, "Welcome " + username));
out.flush();
System.out.println("User logged in successfully: " + username);
}
else{
out.writeObject(new ChatMessage(MessageType.LOGIN_FAILED, "SERVER", "", "Username already taken or invalid."));
out.flush();
closeResources();
return;
}
}
else{
closeResources();
return;
}
// TODO: Main message loop
// In a loop, call in.readObject(), you can separate messages by their type:
// - if it's a ChatMessage -> call handleChatMessage(msg)
// - if it's a FileMessage -> call handleFileMessage(fileMsg)
// Keep looping until the connection is closed (an exception will be thrown).
while (true){
Object received = in.readObject();
if (received instanceof ChatMessage chatMsg){
handleChatMessage(chatMsg);
}
else if (received instanceof FileMessage fileMsg){
handleFileMessage(fileMsg);
}
}
} catch (Exception e) {
System.out.println("Disconnected: " + username);
} finally {
// TODO: Remove the user from UserManager so they no longer
// receive broadcasts or appear in users list
if (username != null){
userManager.removeUser(username);
}
closeResources();
}
}
@@ -48,12 +100,25 @@ public class ClientSession implements Runnable {
switch (msg.getType()) {
case PUBLIC_MESSAGE -> {
// TODO: Broadcast this message to every connected client.
for (ClientSession session : userManager.getAllSessions()) {
session.sendMessage(msg);
}
}
case PRIVATE_MESSAGE -> {
// TODO: Forward this message to the receiver user.
ClientSession receiverSession = userManager.getUser(msg.getReceiver());
if (receiverSession != null){
receiverSession.sendMessage(msg);
}
else{
//Inform sender that the receiver is offline
sendMessage(new ChatMessage(MessageType.PUBLIC_MESSAGE, "SERVER", username, "User " + msg.getReceiver() + " is offline."));
}
}
case USER_LIST -> {
// TODO: Reply to the requester with the list of online users.
String activeUsers = userManager.listUsers();
sendMessage(new ChatMessage(MessageType.USER_LIST, "SERVER", username, activeUsers));
}
}
}
@@ -67,5 +132,32 @@ public class ClientSession implements Runnable {
Files.write(recvPath, fileMsg.getData());
// TODO: Forward the received file-message to the destination user.
ClientSession receiverSession = userManager.getUser(fileMsg.getReceiver());
if (receiverSession != null){
receiverSession.sendFileMessage(fileMsg);
}
}
//to send a regular text message securely
public synchronized void sendMessage(ChatMessage msg) throws IOException {
out.writeObject(msg);
out.flush();
}
//to send a file message securely
public synchronized void sendFileMessage(FileMessage fileMsg) throws IOException {
out.writeObject(fileMsg);
out.flush();
}
private void closeResources() {
try {
if (socket != null && !socket.isClosed()){
socket.close();
}
}
catch (IOException ex){
System.err.println("Error closing socket: " + ex.getMessage());
}
}
}