Minor fixes

Reviewed-on: #6

README.md

@@ -24,12 +24,12 @@ To get started with CRAB, follow these steps:
    ```
 
 2. **Build the project:**
-   Ensure you have Java Development Kit (JDK) of version 17 or higher installed. You can build the project using Maven:
+   Ensure you have Java Development Kit (JDK) of version 17 or higher installed. You can build the project using Gradle:
    ```bash
    ./gradlew clean build
    ```
 
-3. **Run the bundle**: You will have the built .tar and .zip packages in ./build/distributions directory.
+3. **Run the bundle**: You will have the built .jar package in ./build/libs directory.
 
 ## Usage
 
@@ -39,20 +39,44 @@ Once the server is running, clients can connect to it and send messages accordin
 
 1. Message Retrieval
 
-   a. The client initiates a message retrieval session by sending the byte 0x00 to the server.
+   a. The client initiates a message retrieval session by sending the byte `0x00` to the server.
 
    b. In response, the server transmits the size of the available messages as an ASCII-encoded string.
 
-   c. After receiving the size, the client must send the following byte or close the connection:
+   c. After receiving the size, the client must send one of the following bytes or close the connection:
 
-   i. Sending 0x01 instructs the server to transmit the messages.
+   i. Sending `0x01` instructs the server to transmit all messages in full.
+
+   ii. Sending `0x02` followed by the client’s cached messages length (as an ASCII string, e.g., `0x02"1024"`) instructs the server to transmit only new messages added since the cached length. The server sends messages starting from the cached length offset, and the client updates its cached length to the total size received in step 1b after processing the new messages.
 
 2. Message Transmission
 
-   a. To send a message, the client issues a request in the following format:
+   a. To send a message, the client issues a request in one of the following formats:
 
-   0x01 followed immediately by the message content.
+   i. Unauthenticated Message: The client sends the byte `0x01` followed immediately by the message content. The server does not send a response.
+
+   ii. Authenticated Message: The client sends the byte `0x02` followed by the username, a newline character (`\n`), the password, a newline character and the message content. The server responds with a single byte:
+   - `0x01` indicates the user does not exist.
+   - `0x02` indicates the password is incorrect.
+   - A successful authentication results in the server accepting the message without sending a response.
+
+3. User Registration
+
+   a. To register a new user, the client sends a request formatted as:
+   - The byte `0x03`.
+   - The username, followed by a newline character (`\n`).
+   - The password.
+
+   b. The server processes the request and responds with a single byte:
+   - `0x01` if the username already exists.
+   - A successful registration is assumed if no error byte (`0x01`) is received. The client should close the connection after handling the response.
 
 ### Additional Notes:
 
-Although the protocol may appear similar to RACv1, it is important to note that RACv1.99 represents the beta development phase of RACv2. Consequently, significant changes and enhancements are anticipated. The current specification is implemented in lRACd version 1.99.1 and clRAC version 1.99.1.
+- The current specification of RACv2 is implemented in `lRACd` version 2.0.0 and `clRAC` version 2.0.0.
+
+- When using `0x02` for incremental retrieval, the client must ensure the cached length is synchronized with the server’s total message length (retrieved via `0x00`). The server sends messages from the cached length onward, and the client calculates the read size as `(total_length - cached_length)`.
+
+- After receiving incremental messages, the client must update its cached length to the total length provided in step 1b to maintain consistency in subsequent requests.
+
+- For authenticated message transmission (`0x02`) or user registration (`0x03`), the client must follow the specified format precisely. The server validates the structure of the request and responds with error codes only for specific failure conditions (e.g., invalid credentials or duplicate usernames).

src/main/java/net/pixtaded/crab/Main.java

@@ -17,7 +17,7 @@ public class Main {
             case "help" -> {
                 System.out.println("crab help - print this message.");
                 System.out.println("crab client <ip> <port> [nick] - connect to a server.");
-                System.out.println("crab server <port> - start a server.");
+                System.out.println("crab server <port> [PROXY protocol off/on] - start a server.");
             }
             case "client" -> {
                 CrabClient client;
@@ -31,18 +31,23 @@ public class Main {
             }
             case "server" -> {
                 CrabServer server;
-                try {
-                    server = new CrabServer(Integer.parseInt(args[1]));
-                } catch (NumberFormatException e) {
-                    System.err.println("Port is not a number.");
+                if (args.length > 1) {
+                    boolean isProxied = false;
+                    if (args.length > 2)
+                        isProxied = args[2].equals("on");
+                    try {
+                        server = new CrabServer(Integer.parseInt(args[1]), isProxied);
+                    } catch (NumberFormatException e) {
+                        System.err.println("Port is not a number.");
+                        return;
+                    }
+                } else {
+                    System.err.println("Not enough arguments.");
                     return;
                 }
                 server.run();
             }
-            default -> {
-                System.err.println("Unknown argument");
-                return;
-            }
+            default -> System.err.println("Unknown argument");
         }
     }
 

src/main/java/net/pixtaded/crab/client/ClientColor.java

@@ -0,0 +1,4 @@
+package net.pixtaded.crab.client;
+
+public record ClientColor(String regex, String color) {
+}

src/main/java/net/pixtaded/crab/client/ClientUtil.java

@@ -0,0 +1,28 @@
+package net.pixtaded.crab.client;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class ClientUtil {
+
+    public static final String COLOR_KEY = "\u2550\u2550\u2550";
+
+    public static final ClientColor[] colors = {
+            new ClientColor( COLOR_KEY + "(<.*?>)", "\033[0;31m$1\033[0m"),
+            new ClientColor("\uB9AC\u3E70(<.*?>)", "\033[0;32m$1\033[0m"),
+            new ClientColor(" (<.*?>)", " \033[0;34m$1\033[0m"),
+            new ClientColor("\u00B0\u0298(<.*?>)", "\033[0;35m$1\033[0m")
+    };
+
+    public static String clientColors(String s) {
+        for (ClientColor color : colors) s = matchClientKey(s, color);
+        return s;
+    }
+
+    private static String matchClientKey(String s, ClientColor color) {
+        Pattern p = Pattern.compile(color.regex());
+        Matcher m = p.matcher(s);
+
+        return m.replaceAll(color.color());
+    }
+}

src/main/java/net/pixtaded/crab/client/CrabClient.java

@@ -3,6 +3,7 @@ package net.pixtaded.crab.client;
 import net.pixtaded.crab.common.Crab;
 import net.pixtaded.crab.common.Logs;
 import net.pixtaded.crab.common.Sanitizer;
+import net.pixtaded.crab.common.Util;
 
 import java.io.*;
 import java.net.InetSocketAddress;
@@ -29,7 +30,7 @@ public class CrabClient implements Crab {
         this.serverAddress = serverAddress;
         this.port = port;
         if (nickname != null)
-            this.nickname = "<" + nickname + "> ";
+            this.nickname = ClientUtil.COLOR_KEY + "<" + nickname + "> ";
         else
             this.nickname = "";
     }
@@ -70,7 +71,7 @@ public class CrabClient implements Crab {
         System.out.print("Enter your nickname (leave empty for no nickname): ");
         nickname = scanner.nextLine();
         if (!nickname.isEmpty())
-            nickname = "<" + nickname + "> ";
+            nickname = ClientUtil.COLOR_KEY + "<" + nickname + "> ";
     }
 
     private void connect() throws IOException {
@@ -98,7 +99,7 @@ public class CrabClient implements Crab {
 
     private void sendPacket(byte PID, String argument, boolean receiveResponse) throws IOException {
         if (socket == null || socket.isClosed()) connect();
-        String formattedMessage = String.valueOf((char) PID) + argument;
+        String formattedMessage = (char) PID + argument;
 
         out.print(formattedMessage);
         out.flush();
@@ -108,22 +109,23 @@ public class CrabClient implements Crab {
 
     private void printLogs() {
         clearScreen();
-        System.out.print(Sanitizer.sanitizeString(cache.content(), false));
+        System.out.print(ClientUtil.clientColors(Sanitizer.sanitizeString(cache.content(), false)));
     }
 
     private void sendMessage(String msg) throws IOException {
-        sendPacket(COMMUNICATION, this.nickname + msg, false);
+        sendPacket(MESSAGE, this.nickname + msg, false);
         closeConnection();
     }
 
     private void receiveResponse(byte PID) throws IOException {
         switch (PID) {
             case LOGS_SIZE -> {
-                char[] buffer = new char[10];
-                int response = in.read(buffer);
-                String convertedString = new String(buffer).trim();
+                String convertedString = Util.readAsciiNumber(in);
                 if (!convertedString.isEmpty()) lastBufferLength = Integer.parseInt(convertedString);
-            } case COMMUNICATION -> {
+            } case CACHED_LOGS -> {
+                byte[] bytes = socket.getInputStream().readNBytes(lastBufferLength - cache.sizeInBytes());
+                cache = new Logs(lastBufferLength, cache.content() + new String(bytes, StandardCharsets.UTF_8));
+            } case LOGS -> {
                 byte[] bytes = socket.getInputStream().readNBytes(lastBufferLength);
                 cache = new Logs(lastBufferLength, new String(bytes, StandardCharsets.UTF_8));
             } default -> {
@@ -143,8 +145,10 @@ public class CrabClient implements Crab {
 
     private void getLogs() throws IOException {
         sendPacket(LOGS_SIZE, "", true);
-        if (this.cache.sizeInBytes() != lastBufferLength) {
-            sendPacket(COMMUNICATION, "", true);
+        if (this.cache.sizeInBytes() < lastBufferLength) {
+            sendPacket(CACHED_LOGS, String.valueOf(cache.sizeInBytes()), true);
+        } else if (this.cache.sizeInBytes() != lastBufferLength) {
+            sendPacket(LOGS, "", true);
         }
         closeConnection();
         printLogs();
@@ -154,4 +158,4 @@ public class CrabClient implements Crab {
         System.out.print("\033[999999S\033[H\033[2J");
     }
 
-}
+}

src/main/java/net/pixtaded/crab/common/PID.java

@@ -2,5 +2,9 @@ package net.pixtaded.crab.common;
 
 public class PID {
     public static final byte LOGS_SIZE = 0x00;
-    public static final byte COMMUNICATION = 0x01;
-}
+    public static final byte LOGS = 0x01;
+    public static final byte MESSAGE = 0x01;
+    public static final byte CACHED_LOGS = 0x02;
+    public static final byte AUTHENTICATED_MESSAGE = 0x02;
+    public static final byte REGISTER = 0x03;
+}

src/main/java/net/pixtaded/crab/common/Sanitizer.java

@@ -6,6 +6,8 @@ public class Sanitizer {
         if (sanitizeNewlines) {
             sanitized = sanitized.replaceAll("\n", "\\\\n");
             if (!s.endsWith("\n")) sanitized += '\n';
+        } else {
+            sanitized = sanitized.replaceAll("\n\n+", "\n");
         }
         return sanitized;
     }
@@ -13,4 +15,4 @@ public class Sanitizer {
     public static String formatMessage(long timeMillis, String address, String content) {
         return String.format("[%td.%1$tm.%1$tY %1$tR] {%s} %s", timeMillis, address, content);
     }
-}
+}

src/main/java/net/pixtaded/crab/common/Util.java

@@ -0,0 +1,12 @@
+package net.pixtaded.crab.common;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+
+public class Util {
+    public static String readAsciiNumber(BufferedReader in) throws IOException {
+        char[] buffer = new char[10];
+        int response = in.read(buffer);
+        return new String(buffer).trim();
+    }
+}

src/main/java/net/pixtaded/crab/server/CrabServer.java

@@ -3,14 +3,17 @@ import net.pixtaded.crab.common.Crab;
 import net.pixtaded.crab.common.Logs;
 
 import java.io.IOException;
+import java.net.InetAddress;
 import java.net.ServerSocket;
 import java.net.Socket;
+import java.sql.SQLException;
 import java.util.Scanner;
 
 public class CrabServer implements Crab {
 
     private ServerSocket serverSocket;
     private boolean isStopped = false;
+    private boolean isProxied = false;
     private int port;
     private final Database db;
     public Logs cache = new Logs(0, "");
@@ -19,9 +22,10 @@ public class CrabServer implements Crab {
         this.db = new Database("data.db");
     }
 
-    public CrabServer(int port) {
+    public CrabServer(int port, boolean isProxied) {
         this.db = new Database("data.db");
         this.port = port;
+        this.isProxied = isProxied;
     }
 
     @Override
@@ -53,11 +57,28 @@ public class CrabServer implements Crab {
                 System.out.println("Enter a correct port number: ");
             }
         }
+        System.out.print("Enable PROXY protocol? (on/off): ");
+        while (true) {
+            String s = scanner.nextLine();
+            if (s.equals("on")) {
+                this.isProxied = true;
+                break;
+            }
+            if (s.equals("off")) {
+                this.isProxied = false;
+                break;
+            }
+            System.out.println("Enter either \"on\" or \"off\".");
+        }
     }
 
     private void listen() throws IOException {
         Scanner scanner = new Scanner(System.in);
-        serverSocket = new ServerSocket(port);
+        if (this.isProxied) {
+            serverSocket = new ServerSocket(port, 0, InetAddress.getLoopbackAddress());
+        } else {
+            serverSocket = new ServerSocket(port);
+        }
         System.out.printf("Server successfully started! Listening on port %s.\nTo stop the server, type 'q'.\n", port);
         ServerCLI cli = new ServerCLI(scanner, this);
         new Thread(cli).start();
@@ -72,8 +93,11 @@ public class CrabServer implements Crab {
         isStopped = true;
         try {
             if (serverSocket != null) serverSocket.close();
+            getDb().close();
         } catch (IOException e) {
             System.err.println("An error occured while closing the socket: " + e.getMessage());
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
         } finally {
             System.exit(0);
         }
@@ -82,4 +106,8 @@ public class CrabServer implements Crab {
     public Database getDb() {
         return db;
     }
+
+    public boolean isProxied() {
+        return this.isProxied;
+    }
 }

src/main/java/net/pixtaded/crab/server/Database.java

@@ -6,7 +6,7 @@ import net.pixtaded.crab.common.Sanitizer;
 import java.sql.*;
 import java.util.Date;
 
-public class Database implements AutoCloseable {
+public class Database {
 
     private Connection connection;
 
@@ -62,10 +62,7 @@ public class Database implements AutoCloseable {
         return new Logs(logsString.isEmpty() ? 0 : logsString.getBytes().length, logsString);
     }
 
-    @Override
     public void close() throws SQLException {
-        if (connection != null && !connection.isClosed()) {
-            connection.close();
-        }
+        connection.close();
     }
 }

src/main/java/net/pixtaded/crab/server/ServerThread.java

@@ -2,23 +2,24 @@ package net.pixtaded.crab.server;
 
 import net.pixtaded.crab.common.Logs;
 import net.pixtaded.crab.common.Sanitizer;
+import net.pixtaded.crab.common.Util;
 
 import java.io.*;
 import java.net.Socket;
 import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
 import java.util.Date;
 
 import static net.pixtaded.crab.common.PID.*;
 
 public class ServerThread implements Runnable {
 
-    private Socket socket;
-    private PrintWriter out;
-    private BufferedReader in;
-    private OutputStream output;
-    private InputStream input;
-    private byte PID;
-    private CrabServer server;
+    private final Socket socket;
+    private final PrintWriter out;
+    private final BufferedReader in;
+    private final OutputStream output;
+    private final InputStream input;
+    private final CrabServer server;
 
     public ServerThread(Socket socket, CrabServer server) throws IOException {
         this.socket = socket;
@@ -37,11 +38,40 @@ public class ServerThread implements Runnable {
                 socket.close();
                 return;
             }
+            String address = socket.getInetAddress().getHostAddress();
+            if (PID[0] == 'P') {
+                if (!this.server.isProxied()) {
+                    System.err.println(address + " tried to use PROXY despite it being off.");
+                    socket.close();
+                    return;
+                }
+                if (Arrays.equals(readUntilChar(' '),"ROXY".getBytes())) {
+                    readUntilChar(' '); // proto
+                    byte[] source = readUntilChar(' ');
+                    address = new String(source);
+                    readUntilChar(' '); // destination IP
+                    readUntilChar(' '); // source port
+                    readUntilChar('\r'); // destination port
+                    if (input.read() != '\n') {
+                        System.err.println("Invalid PROXY packet.");
+                        socket.close();
+                        return;
+                    }
+                } else {
+                    System.err.println("Invalid PROXY packet header.");
+                    socket.close();
+                    return;
+                }
+                PID = readPID();
+		        if (PID.length == 0) {
+			        socket.close();
+			        return;
+		        }
+            } 
             switch (PID[0]) {
-                case COMMUNICATION -> {
+                case MESSAGE -> {
                     String msg = new String(input.readNBytes(4096), StandardCharsets.UTF_8).trim();
                     Date date = new Date();
-                    String address = socket.getInetAddress().getHostAddress();
 
                     String s = Sanitizer.sanitizeString(msg, true);
                     String newContent = server.cache.content() + Sanitizer.formatMessage(date.getTime(), address, s);
@@ -50,11 +80,13 @@ public class ServerThread implements Runnable {
                     new Thread(new LogDBThread(date, address, msg)).start();
                 } case LOGS_SIZE -> {
                     respond(String.valueOf(server.cache.sizeInBytes()));
-                    readPID();
-                    sendLogs();
-                } default -> {
-                    System.out.println("PID not implemented: " + PID[0]);
-                }
+                    byte[] logPID = readPID();
+                    if (logPID.length == 0) {
+                        socket.close();
+                        return;
+                    }
+                    sendLogs(logPID[0]);
+                } default -> System.out.println("PID not implemented: " + PID[0]);
             }
             socket.close();
         } catch (Exception e) {
@@ -66,8 +98,31 @@ public class ServerThread implements Runnable {
         return input.readNBytes(1);
     }
 
-    private void sendLogs() throws IOException {
-        respond(server.cache.content());
+    private byte[] readUntilChar(char c) throws IOException {
+        byte[] b = new byte[256];
+        int i;
+        for (i = 0;; i++) {
+            b[i] = (byte)input.read();
+            if (b[i] == c)
+                break;
+        }
+        byte[] r = new byte[i];
+        System.arraycopy(b, 0, r, 0, i);
+        return r;
+    }
+
+    private void sendLogs(byte PID) throws IOException {
+        if (PID == LOGS) {
+            respond(server.cache.content());
+        } else if (PID == CACHED_LOGS) {
+            String clientSize = Util.readAsciiNumber(in);
+            int clientSizeNum = Integer.parseInt(clientSize);
+            byte[] serverLogs = server.cache.content().getBytes(StandardCharsets.UTF_8);
+            int logPartSize = serverLogs.length - clientSizeNum;
+            byte[] logPart = new byte[logPartSize];
+            System.arraycopy(serverLogs, serverLogs.length - logPartSize, logPart, 0, logPartSize);
+            respond(logPart);
+        }
     }
 
     private void respond(byte[] data) throws IOException {