Initial commit

.gitignore

@@ -0,0 +1,42 @@
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### IntelliJ IDEA ###
+.idea/modules.xml
+.idea/jarRepositories.xml
+.idea/compiler.xml
+.idea/libraries/
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

.idea/.gitignore

@@ -0,0 +1,3 @@
+# Default ignored files
+/shelf/
+/workspace.xml

.idea/gradle.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GradleMigrationSettings" migrationVersion="1" />
+  <component name="GradleSettings">
+    <option name="linkedExternalProjectsSettings">
+      <GradleProjectSettings>
+        <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleHome" value="" />
+        <option name="modules">
+          <set>
+            <option value="$PROJECT_DIR$" />
+          </set>
+        </option>
+      </GradleProjectSettings>
+    </option>
+  </component>
+</project>

.idea/misc.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="17" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

build.gradle

@@ -0,0 +1,19 @@
+plugins {
+    id 'java'
+    id 'application'
+}
+
+group = 'net.pixtaded'
+version = '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+application {
+    mainClass = 'net.pixtaded.crab.Main'
+}
+
+dependencies {
+    implementation('org.xerial:sqlite-jdbc:3.47.1.0')
+}

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Wed Dec 18 17:40:42 MSK 2024
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.10-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

@@ -0,0 +1,2 @@
+rootProject.name = 'crab'
+

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

@@ -0,0 +1,31 @@
+package net.pixtaded.crab;
+
+import net.pixtaded.crab.client.CrabClient;
+import net.pixtaded.crab.server.CrabServer;
+
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        chooseMode(scanner);
+        scanner.close();
+    }
+
+    private static void chooseMode(Scanner scanner) {
+        System.out.println("Choose mode (1 - client, 2 - server): ");
+
+        int choice = scanner.nextInt();
+
+        if (choice == 1) {
+            CrabClient client = new CrabClient();
+            client.run();
+        } else if (choice == 2) {
+            CrabServer server = new CrabServer();
+            server.run();
+        } else {
+            chooseMode(scanner);
+        }
+    }
+
+}

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

@@ -0,0 +1,123 @@
+package net.pixtaded.crab.client;
+
+import net.pixtaded.crab.common.Crab;
+import net.pixtaded.crab.common.Sanitizer;
+
+import java.io.*;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.nio.charset.StandardCharsets;
+import java.util.Scanner;
+import static net.pixtaded.crab.common.PID.*;
+
+public class CrabClient implements Crab {
+    private String serverAddress;
+    private int port;
+    private Socket socket;
+    private PrintWriter out;
+    private BufferedReader in;
+    private int lastBufferLength = 0;
+
+    public CrabClient() {
+
+    }
+
+    @Override
+    public void run() {
+        try {
+            setup();
+            connect();
+            communicate();
+        } catch (IOException e) {
+            System.err.println("Error connecting to the server: " + e.getMessage());
+        } finally {
+            closeConnection();
+        }
+    }
+
+    private void setup() {
+        Scanner scanner = new Scanner(System.in);
+
+        System.out.print("Enter server address: ");
+        serverAddress = scanner.nextLine();
+
+        System.out.print("Enter the port: ");
+        while (true) {
+            try {
+                port = Integer.parseInt(scanner.nextLine());
+                if (port > 0 && port <= 65535) {
+                    break;
+                } else {
+                    System.out.println("Enter the correct port (1-65535): ");
+                }
+            } catch (NumberFormatException e) {
+                System.out.println("Enter a correct port number: ");
+            }
+        }
+    }
+
+    private void connect() throws IOException {
+        socket = new Socket();
+        socket.connect(new InetSocketAddress(serverAddress, port), 2000);
+        out = new PrintWriter(socket.getOutputStream(), true);
+        in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+    }
+
+    private void communicate() throws IOException {
+        Scanner scanner = new Scanner(System.in);
+        String message;
+
+        while (true) {
+            System.out.print("\033[H\033[2J");
+            getLogs();
+            System.out.print("Enter a message (or type '/exit' to exit): ");
+            message = scanner.nextLine();
+
+            if (message.equalsIgnoreCase("/exit")) {
+                break;
+            }
+
+            if (!message.isEmpty()) sendPacket(MESSAGE, message);
+        }
+    }
+
+    private void sendPacket(byte PID, String argument) throws IOException {
+        String formattedMessage = String.valueOf((char) PID) + argument + "\n";
+
+        out.print(formattedMessage);
+        out.flush();
+
+        receiveResponse(PID);
+    }
+
+    private void receiveResponse(byte PID) throws IOException {
+        switch (PID) {
+            case LOGS_SIZE -> {
+                char[] buffer = new char[10];
+                int response = in.read(buffer);
+                lastBufferLength = Integer.parseInt(new String(buffer).trim());
+            } case LOGS -> {
+                byte[] bytes = socket.getInputStream().readNBytes(lastBufferLength);
+                System.out.print(Sanitizer.sanitizeString(new String(bytes, StandardCharsets.UTF_8), false));
+            } default -> {
+            }
+        }
+        closeConnection();
+        connect();
+    }
+
+    private void closeConnection() {
+        try {
+            if (in != null) in.close();
+            if (out != null) out.close();
+            if (socket != null) socket.close();
+        } catch (IOException e) {
+            System.err.println("An error occured while closing the connection: " + e.getMessage());
+        }
+    }
+
+    private void getLogs() throws IOException {
+        sendPacket(LOGS_SIZE, "");
+        sendPacket(LOGS, "");
+    }
+}

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

@@ -0,0 +1,5 @@
+package net.pixtaded.crab.common;
+
+public interface Crab {
+    void run();
+}

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

@@ -0,0 +1,7 @@
+package net.pixtaded.crab.common;
+
+public class PID {
+    public static final byte MESSAGE = 0x30;
+    public static final byte LOGS_SIZE = 0x31;
+    public static final byte LOGS = 0x32;
+}

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

@@ -0,0 +1,12 @@
+package net.pixtaded.crab.common;
+
+public class Sanitizer {
+    public static String sanitizeString(String s, boolean sanitizeNewlines) {
+        String sanitized = s.replaceAll("\033", "");
+        if (sanitizeNewlines) {
+            sanitized = sanitized.replaceAll("\n", "\\\\n");
+            if (!s.endsWith("\n")) sanitized += '\n';
+        }
+        return sanitized;
+    }
+}

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

@@ -0,0 +1,78 @@
+package net.pixtaded.crab.server;
+import net.pixtaded.crab.common.Crab;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.Scanner;
+
+public class CrabServer implements Crab {
+
+    private ServerSocket serverSocket;
+    private Socket socket;
+    private boolean isStopped = false;
+    private int port;
+    private Database db;
+
+    public CrabServer() {
+        this.db = new Database("data.db");
+    }
+
+    @Override
+    public void run() {
+        try {
+            setup();
+            listen();
+        } catch (IOException e) {
+            if (!isStopped) System.err.println("Error starting server: " + e.getMessage());
+        } finally {
+            stop();
+        }
+    }
+
+    private void setup() {
+        Scanner scanner = new Scanner(System.in);
+        System.out.print("Enter server port: ");
+        while (true) {
+            try {
+                port = Integer.parseInt(scanner.nextLine());
+                if (port > 0 && port <= 65535) {
+                    break;
+                } else {
+                    System.out.println("Enter a correct port (1-65535): ");
+                }
+            } catch (NumberFormatException e) {
+                System.out.println("Enter a correct port number: ");
+            }
+        }
+    }
+
+    private void listen() throws IOException {
+        Scanner scanner = new Scanner(System.in);
+        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();
+        while (!isStopped) {
+            Socket socket = serverSocket.accept();
+            ServerThread thread = new ServerThread(socket, this);
+            new Thread(thread).start();
+        }
+    }
+
+    public void stop() {
+        try {
+            isStopped = true;
+            if (socket != null) socket.close();
+            if (serverSocket != null) serverSocket.close();
+        } catch (IOException e) {
+            System.err.println("An error occured while closing the socket: " + e.getMessage());
+        } finally {
+            System.exit(0);
+        }
+    }
+
+    public Database getDb() {
+        return db;
+    }
+}

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

@@ -0,0 +1,71 @@
+package net.pixtaded.crab.server;
+
+import net.pixtaded.crab.common.Sanitizer;
+
+import java.sql.*;
+import java.util.Date;
+import java.util.Locale;
+
+public class Database {
+
+    private Connection connection;
+    private String logs = "";
+
+    public Database(String dbName) {
+        try {
+            connection = DriverManager.getConnection("jdbc:sqlite:./" + dbName);
+            createTable();
+        } catch (SQLException e) {
+            System.err.println("Failed to connect to database: " + e.getMessage());
+        }
+    }
+
+    private void createTable() throws SQLException {
+        execute("CREATE TABLE IF NOT EXISTS messages (time INTEGER PRIMARY KEY, address TEXT NOT NULL, msg TEXT NOT NULL) STRICT"); // almatyd format
+    }
+
+    public ResultSet query(String q) throws SQLException {
+        Statement statement = connection.createStatement();
+        ResultSet rs = statement.executeQuery(q);
+        if (!rs.isAfterLast()) {
+            return rs;
+        } else return null;
+    }
+
+    public void execute(String q) throws SQLException {
+        Statement statement = connection.createStatement();
+        statement.execute(q);
+        statement.close();
+    }
+
+    public void logMessage(Date date, String address, String message) {
+        String sql = "INSERT INTO messages (time, address, msg) VALUES (?, ?, ?)";
+        try (PreparedStatement pstmt = connection.prepareStatement(sql)) {
+            pstmt.setLong(1, date.getTime());
+            pstmt.setString(2, address);
+            pstmt.setString(3, Sanitizer.sanitizeString(message, true));
+            pstmt.executeUpdate();
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public String getLogs() {
+        StringBuilder s = new StringBuilder();
+        try (ResultSet rs = query("SELECT time, address, msg FROM messages")) {
+            while (rs.next()) {
+                s.append(String.format("[%td.%1$tm.%1$tY %1$tR] {%s} %s", rs.getLong(1), rs.getString(2), rs.getString(3)));
+            }
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        logs = s.toString();
+        return logs;
+    }
+
+    public int getLogSize() {
+        if (logs.isEmpty()) return 0;
+        else return logs.getBytes().length;
+    }
+
+}

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

@@ -0,0 +1,25 @@
+package net.pixtaded.crab.server;
+
+import java.util.Scanner;
+
+public class ServerCLI implements Runnable {
+
+    Scanner scanner;
+    CrabServer server;
+
+    public ServerCLI(Scanner scanner, CrabServer server) {
+        this.scanner = scanner;
+        this.server = server;
+    }
+
+    @Override
+    public void run() {
+        while (true) {
+            if (scanner.nextLine().equalsIgnoreCase("q")) {
+                System.out.println("The server is stopping...");
+                server.stop();
+                break;
+            }
+        }
+    }
+}

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

@@ -0,0 +1,59 @@
+package net.pixtaded.crab.server;
+
+import java.io.*;
+import java.net.Socket;
+import java.nio.charset.StandardCharsets;
+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;
+
+    public ServerThread(Socket socket, CrabServer server) throws IOException {
+        this.socket = socket;
+        this.out = new PrintWriter(socket.getOutputStream(), true);
+        this.in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+        this.output = socket.getOutputStream();
+        this.input = socket.getInputStream();
+        this.server = server;
+    }
+
+    @Override
+    public void run() {
+        try {
+            byte[] PID = input.readNBytes(1);
+            switch (PID[0]) {
+                case MESSAGE -> {
+                    server.getDb().logMessage(new Date(), socket.getInetAddress().getHostAddress(), new String(input.readNBytes(4096), StandardCharsets.UTF_8).trim());
+                    socket.close();
+                } case LOGS -> {
+                    respond(server.getDb().getLogs());
+                } case LOGS_SIZE -> {
+                    respond(String.valueOf(server.getDb().getLogSize()));
+                } default -> {
+                    System.out.println("PID not implemented: " + PID[0]);
+                }
+            }
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void respond(byte[] data) throws IOException {
+        socket.getOutputStream().write(data);
+        socket.getOutputStream().flush();
+        socket.close();
+    }
+
+    private void respond(String utf8) throws IOException {
+        respond(utf8.getBytes(StandardCharsets.UTF_8));
+    }
+}