From 11d776da151bb0fff907fb886cac145f66d17f75 Mon Sep 17 00:00:00 2001 From: Fatemesadat Mirabootalebi Date: Fri, 19 Jun 2026 13:42:25 -0700 Subject: [PATCH] Completed Network File-Sharing Chat System backend and client logic --- .idea/misc.xml | 2 +- .../chat/Client/ServerListener.java | 15 +++ .../university/chat/Client/chatClient.java | 107 +++++++++++++++++- .../university/chat/Server/ChatServer.java | 18 +++ .../university/chat/Server/ClientSession.java | 94 ++++++++++++++- 5 files changed, 229 insertions(+), 7 deletions(-) diff --git a/.idea/misc.xml b/.idea/misc.xml index d2b5d0f..0d65d63 100644 --- a/.idea/misc.xml +++ b/.idea/misc.xml @@ -8,7 +8,7 @@ - + \ No newline at end of file diff --git a/src/main/java/com/university/chat/Client/ServerListener.java b/src/main/java/com/university/chat/Client/ServerListener.java index b609d74..1fb8e06 100644 --- a/src/main/java/com/university/chat/Client/ServerListener.java +++ b/src/main/java/com/university/chat/Client/ServerListener.java @@ -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"); } diff --git a/src/main/java/com/university/chat/Client/chatClient.java b/src/main/java/com/university/chat/Client/chatClient.java index dae0bad..a5c98b2 100644 --- a/src/main/java/com/university/chat/Client/chatClient.java +++ b/src/main/java/com/university/chat/Client/chatClient.java @@ -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 , /users, /sendfile , 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 " -> 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 "); + } + } + 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 " -> 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 "); + } + } + 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()); + } +}} diff --git a/src/main/java/com/university/chat/Server/ChatServer.java b/src/main/java/com/university/chat/Server/ChatServer.java index b2a35ae..90b42ca 100644 --- a/src/main/java/com/university/chat/Server/ChatServer.java +++ b/src/main/java/com/university/chat/Server/ChatServer.java @@ -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()); + } } } diff --git a/src/main/java/com/university/chat/Server/ClientSession.java b/src/main/java/com/university/chat/Server/ClientSession.java index f09d64a..73da81b 100644 --- a/src/main/java/com/university/chat/Server/ClientSession.java +++ b/src/main/java/com/university/chat/Server/ClientSession.java @@ -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()); + } } } \ No newline at end of file