Convert auth-system to plugin

.gitignore

@@ -4,6 +4,12 @@
 # Log file
 *.log
 
+# Intellij
+.idea
+
+# Output of the build
+out
+
 # BlueJ files
 *.ctxt
 

.gradle/buildOutputCleanup/cache.properties

@@ -0,0 +1,2 @@
+#Thu Apr 28 11:29:29 WIB 2022
+gradle.version=7.2

build.gradle

@@ -0,0 +1,21 @@
+plugins {
+    id 'java'
+}
+
+group 'me.exzork.gcauth'
+version '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation group: 'tech.xigam', name: 'grasscutter', version: '1.0.2-dev'
+    implementation 'io.jsonwebtoken:jjwt-api:0.11.3'
+    runtimeOnly 'io.jsonwebtoken:jjwt-impl:0.11.3', 'io.jsonwebtoken:jjwt-gson:0.11.3'
+    implementation 'org.springframework.security:spring-security-crypto:5.6.3'
+}
+
+test {
+    useJUnitPlatform()
+}

build/resources/main/plugin.json

@@ -0,0 +1,7 @@
+{
+  "name": "GCAuth",
+  "description": "GCAuth is a plugin that allows you to implement authentication for your server.",
+  "version": "1.0.0",
+  "author": ["ExZork"],
+  "mainClass": "me.exzork.gcauth.GCAuth"
+}

build/tmp/jar/MANIFEST.MF

@@ -0,0 +1,3 @@
+Manifest-Version: 1.0
+Main-Class: me.exzork.gcauth.GCAuth
+

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,185 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or 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 UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MSYS* | MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$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" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+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 = 'GCAuth'
+

src/main/java/me/exzork/gcauth/Config.java

@@ -0,0 +1,6 @@
+package me.exzork.gcauth;
+
+public final class Config {
+    public String Hash = "BCRYPT";
+    public boolean Enable = true;
+}

src/main/java/me/exzork/gcauth/GCAuth.java

@@ -0,0 +1,68 @@
+package me.exzork.gcauth;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.sun.net.httpserver.HttpServer;
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.plugin.Plugin;
+import me.exzork.gcauth.handler.AuthStatusHandler;
+import me.exzork.gcauth.handler.ChangePasswordHandler;
+import me.exzork.gcauth.handler.LoginHandler;
+import me.exzork.gcauth.handler.RegisterHandler;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+
+public class GCAuth extends Plugin {
+    private static Config config;
+    private static final File configFile = new File(Grasscutter.getConfig().PLUGINS_FOLDER+"GCAuth/config.json");
+    private static final Gson gson = new GsonBuilder().setPrettyPrinting().create();
+    @Override
+    public void onLoad() {
+        if (!configFile.exists()) {
+            try {
+                Files.createDirectories(configFile.toPath().getParent());
+            } catch (IOException e) {
+                Grasscutter.getLogger().error("Failed to create config.json for GCAuth");
+            }
+        }
+        loadConfig();
+    }
+
+    @Override
+    public void onEnable() {
+        HttpServer server = Grasscutter.getDispatchServer().getServer();
+        server.createContext("/grasscutter/auth_status",new AuthStatusHandler());
+        server.createContext("/grasscutter/login", new LoginHandler());
+        server.createContext("/grasscutter/register", new RegisterHandler());
+        server.createContext("/grasscutter/change_password", new ChangePasswordHandler());
+    }
+
+    @Override
+    public void onDisable() {
+        super.onDisable();
+    }
+
+    public static void loadConfig() {
+        try (FileReader file = new FileReader(configFile)) {
+            config = gson.fromJson(file,Config.class);
+            saveConfig();
+        } catch (Exception e) {
+            config = new Config();
+            saveConfig();
+        }
+    }
+
+    public static void saveConfig() {
+        try (FileWriter file = new FileWriter(configFile)) {
+            file.write(gson.toJson(config));
+        } catch (Exception e) {
+            Grasscutter.getLogger().error("Unable to save config file.");
+        }
+    }
+
+    public static Config getConfig() {return config;}
+}

src/main/java/me/exzork/gcauth/handler/AbstractHandler.java

@@ -0,0 +1,23 @@
+package me.exzork.gcauth.handler;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import emu.grasscutter.Grasscutter;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Collections;
+
+public abstract class AbstractHandler implements HttpHandler {
+    void responseJSON(HttpExchange t, Object data) throws IOException {
+        // Create a response
+        String response = Grasscutter.getGsonFactory().toJson(data);
+        // Set the response header status and length
+        t.getResponseHeaders().put("Content-Type", Collections.singletonList("application/json"));
+        t.sendResponseHeaders(200, response.getBytes().length);
+        // Write the response string
+        OutputStream os = t.getResponseBody();
+        os.write(response.getBytes());
+        os.close();
+    }
+}

src/main/java/me/exzork/gcauth/handler/AuthStatusHandler.java

@@ -0,0 +1,18 @@
+package me.exzork.gcauth.handler;
+
+import com.sun.net.httpserver.HttpExchange;
+import me.exzork.gcauth.GCAuth;
+import me.exzork.gcauth.json.AuthResponseJson;
+
+import java.io.IOException;
+
+public class AuthStatusHandler extends AbstractHandler{
+    @Override
+    public void handle(HttpExchange t) throws IOException {
+        AuthResponseJson authResponse = new AuthResponseJson();
+        authResponse.success = true;
+        authResponse.message = GCAuth.getConfig().Enable ? "AUTH_ENABLED" : "AUTH_DISABLED";
+        authResponse.jwt = "";
+        responseJSON(t, authResponse);
+    }
+}

src/main/java/me/exzork/gcauth/handler/ChangePasswordHandler.java

@@ -0,0 +1,64 @@
+package me.exzork.gcauth.handler;
+
+import com.google.gson.Gson;
+import com.sun.net.httpserver.HttpExchange;
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.game.Account;
+import emu.grasscutter.utils.Utils;
+import me.exzork.gcauth.GCAuth;
+import me.exzork.gcauth.json.AuthResponseJson;
+import me.exzork.gcauth.json.ChangePasswordAccount;
+import me.exzork.gcauth.utils.Authentication;
+
+import java.io.IOException;
+
+public class ChangePasswordHandler extends AbstractHandler{
+    @Override
+    public void handle(HttpExchange t) throws IOException {
+        AuthResponseJson authResponse = new AuthResponseJson();
+
+        if (GCAuth.getConfig().Enable) {
+            try {
+                String requestBody = Utils.toString(t.getRequestBody());
+                if (requestBody.isEmpty()) {
+                    authResponse.success = false;
+                    authResponse.message = "EMPTY_BODY"; // ENG = "No data was sent with the request"
+                    authResponse.jwt = "";
+                } else {
+                    ChangePasswordAccount changePasswordAccount = new Gson().fromJson(requestBody, ChangePasswordAccount.class);
+                    if (changePasswordAccount.new_password.equals(changePasswordAccount.new_password_confirmation)) {
+                        Account account = Authentication.getAccountByUsernameAndPassword(changePasswordAccount.username, changePasswordAccount.old_password);
+                        if (account == null) {
+                            authResponse.success = false;
+                            authResponse.message = "INVALID_ACCOUNT"; // ENG = "Invalid username or password"
+                            authResponse.jwt = "";
+                        }
+                        String newPassword = Authentication.generateHash(changePasswordAccount.new_password);
+                        account.setPassword(newPassword);
+                        account.save();
+                        authResponse.success = true;
+                        authResponse.message = "";
+                        authResponse.jwt = "";
+                    } else {
+                        authResponse.success = false;
+                        authResponse.message = "PASSWORD_MISMATCH"; // ENG = "Passwords do not match."
+                        authResponse.jwt = "";
+                    }
+                }
+            } catch (Exception e) {
+                authResponse.success = false;
+                authResponse.message = "UNKNOWN"; // ENG = "An unknown error has occurred..."
+                authResponse.jwt = "";
+                Grasscutter.getLogger().error("[Dispatch] Error while changing user password.");
+                e.printStackTrace();
+                responseJSON(t, authResponse);
+            }
+        } else {
+            authResponse.success = false;
+            authResponse.message = "AUTH_DISABLED"; // ENG = "Authentication is not required for this server..."
+            authResponse.jwt = "";
+        }
+
+        responseJSON(t, authResponse);
+    }
+}

src/main/java/me/exzork/gcauth/handler/LoginHandler.java

@@ -0,0 +1,61 @@
+package me.exzork.gcauth.handler;
+
+import com.google.gson.Gson;
+import com.sun.net.httpserver.HttpExchange;
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.game.Account;
+import emu.grasscutter.utils.Utils;
+import me.exzork.gcauth.GCAuth;
+import me.exzork.gcauth.json.AuthResponseJson;
+import me.exzork.gcauth.json.LoginGenerateToken;
+import me.exzork.gcauth.utils.Authentication;
+
+import java.io.IOException;
+
+public class LoginHandler extends AbstractHandler{
+    @Override
+    public void handle(HttpExchange t) throws IOException {
+        AuthResponseJson authResponse = new AuthResponseJson();
+
+        if (GCAuth.getConfig().Enable) {
+            try {
+                String requestBody = Utils.toString(t.getRequestBody());
+                if (requestBody.isEmpty()) {
+                    authResponse.success = false;
+                    authResponse.message = "EMPTY_BODY"; // ENG = "No data was sent with the request"
+                    authResponse.jwt = "";
+                } else {
+                    LoginGenerateToken loginGenerateToken = new Gson().fromJson(requestBody, LoginGenerateToken.class);
+                    Account account = Authentication.getAccountByUsernameAndPassword(loginGenerateToken.username, loginGenerateToken.password);
+                    if (account == null) {
+                        authResponse.success = false;
+                        authResponse.message = "INVALID_ACCOUNT"; // ENG = "Invalid username or password"
+                        authResponse.jwt = "";
+                    } else {
+                        if (account.getPassword() != null && !account.getPassword().isEmpty()) {
+                            authResponse.success = true;
+                            authResponse.message = "";
+                            authResponse.jwt = Authentication.generateJwt(account);
+                        } else {
+                            authResponse.success = false;
+                            authResponse.message = "NO_PASSWORD"; // ENG = "There is no account password set. Please create a password by resetting it."
+                            authResponse.jwt = "";
+                        }
+                    }
+                }
+            } catch (Exception e) {
+                authResponse.success = false;
+                authResponse.message = "UNKNOWN"; // ENG = "An unknown error has occurred..."
+                authResponse.jwt = "";
+                Grasscutter.getLogger().error("[Dispatch] An error occurred while a user was logging in.");
+                e.printStackTrace();
+            }
+        } else {
+            authResponse.success = false;
+            authResponse.message = "AUTH_DISABLED"; // ENG = "Authentication is not required for this server..."
+            authResponse.jwt = "";
+        }
+
+        responseJSON(t, authResponse);
+    }
+}

src/main/java/me/exzork/gcauth/handler/RegisterHandler.java

@@ -0,0 +1,63 @@
+package me.exzork.gcauth.handler;
+
+import com.google.gson.Gson;
+import com.sun.net.httpserver.HttpExchange;
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.database.DatabaseHelper;
+import emu.grasscutter.game.Account;
+import emu.grasscutter.utils.Utils;
+import me.exzork.gcauth.GCAuth;
+import me.exzork.gcauth.json.AuthResponseJson;
+import me.exzork.gcauth.json.RegisterAccount;
+import me.exzork.gcauth.utils.Authentication;
+
+import java.io.IOException;
+
+public class RegisterHandler extends AbstractHandler{
+    @Override
+    public void handle(HttpExchange t) throws IOException {
+        AuthResponseJson authResponse = new AuthResponseJson();
+
+        if (GCAuth.getConfig().Enable) {
+            try {
+                String requestBody = Utils.toString(t.getRequestBody());
+                if (requestBody.isEmpty()) {
+                    authResponse.success = false;
+                    authResponse.message = "EMPTY_BODY"; // ENG = "No data was sent with the request"
+                    authResponse.jwt = "";
+                } else {
+                    RegisterAccount registerAccount = new Gson().fromJson(requestBody, RegisterAccount.class);
+                    if (registerAccount.password.equals(registerAccount.password_confirmation)) {
+                        String password = Authentication.generateHash(registerAccount.password);
+                        Account account = DatabaseHelper.createAccountWithPassword(registerAccount.username, password);
+                        if (account == null) {
+                            authResponse.success = false;
+                            authResponse.message = "USERNAME_TAKEN"; // ENG = "Username has already been taken by another user."
+                            authResponse.jwt = "";
+                        } else {
+                            authResponse.success = true;
+                            authResponse.message = "";
+                            authResponse.jwt = "";
+                        }
+                    } else {
+                        authResponse.success = false;
+                        authResponse.message = "PASSWORD_MISMATCH"; // ENG = "Passwords do not match."
+                        authResponse.jwt = "";
+                    }
+                }
+            } catch (Exception e) {
+                authResponse.success = false;
+                authResponse.message = "UNKNOWN"; // ENG = "An unknown error has occurred..."
+                authResponse.jwt = "";
+                Grasscutter.getLogger().error("[Dispatch] An error occurred while creating an account.");
+                e.printStackTrace();
+            }
+        } else {
+            authResponse.success = false;
+            authResponse.message = "AUTH_DISABLED"; // ENG = "Authentication is not required for this server..."
+            authResponse.jwt = "";
+        }
+
+        responseJSON(t, authResponse);
+    }
+}

src/main/java/me/exzork/gcauth/json/AuthResponseJson.java

@@ -0,0 +1,7 @@
+package me.exzork.gcauth.json;
+
+public class AuthResponseJson {
+    public boolean success;
+    public String message;
+    public String jwt;
+}

src/main/java/me/exzork/gcauth/json/ChangePasswordAccount.java

@@ -0,0 +1,8 @@
+package me.exzork.gcauth.json;
+
+public class ChangePasswordAccount {
+    public String username;
+    public String new_password;
+    public String new_password_confirmation;
+    public String old_password;
+}

src/main/java/me/exzork/gcauth/json/LoginGenerateToken.java

@@ -0,0 +1,6 @@
+package me.exzork.gcauth.json;
+
+public class LoginGenerateToken {
+    public String username;
+    public String password;
+}

src/main/java/me/exzork/gcauth/json/RegisterAccount.java

@@ -0,0 +1,7 @@
+package me.exzork.gcauth.json;
+
+public class RegisterAccount {
+    public String username;
+    public String password;
+    public String password_confirmation;
+}

src/main/java/me/exzork/gcauth/utils/Authentication.java

@@ -0,0 +1,65 @@
+package me.exzork.gcauth.utils;
+
+import emu.grasscutter.database.DatabaseHelper;
+import emu.grasscutter.game.Account;
+import io.jsonwebtoken.SignatureAlgorithm;
+import io.jsonwebtoken.security.Keys;
+import me.exzork.gcauth.GCAuth;
+import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.security.crypto.scrypt.SCryptPasswordEncoder;
+import io.jsonwebtoken.Jwts;
+
+import javax.crypto.SecretKey;
+import java.util.HashMap;
+
+public final class Authentication {
+    public static final HashMap<String,String> tokens = new HashMap<String,String>();
+    private static SecretKey key = Keys.secretKeyFor(SignatureAlgorithm.HS256);
+    public static SecretKey getKey() {
+        return key;
+    }
+
+    public static Account getAccountByUsernameAndPassword(String username, String password) {
+        Account account = DatabaseHelper.getAccountByName(username);
+        if(account.getPassword() != null && !account.getPassword().isEmpty()) {
+            if(!verifyPassword(password, account.getPassword())) account = null;
+        }
+        return account;
+    }
+
+    public static String generateOneTimeToken(Account account) {
+        String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+        StringBuilder sb = new StringBuilder();
+        for(int i = 0; i < 32; i++) {
+            sb.append(chars.charAt((int) (Math.random() * chars.length())));
+        }
+        Authentication.tokens.put(sb.toString(), account.getUsername());
+        return sb.toString();
+    }
+
+    public static String generateJwt(Account account) {
+        String jws = Jwts.builder()
+                .signWith(Authentication.getKey())
+                .claim("token",generateOneTimeToken(account))
+                .claim("username",account.getUsername())
+                .claim("uid",account.getPlayerUid())
+                .compact();
+        return jws;
+    }
+
+    public static String generateHash(String password) {
+        return switch (GCAuth.getConfig().Hash.toLowerCase()) {
+            case "bcrypt" -> new BCryptPasswordEncoder().encode(password);
+            case "scrypt" -> new SCryptPasswordEncoder().encode(password);
+            default -> password;
+        };
+    }
+
+    private static boolean verifyPassword(String password, String hash) {
+        return switch (GCAuth.getConfig().Hash.toLowerCase()) {
+            case "bcrypt" -> new BCryptPasswordEncoder().matches(password, hash);
+            case "scrypt" -> new SCryptPasswordEncoder().matches(password, hash);
+            default -> password.equals(hash);
+        };
+    }
+}

src/main/resources/plugin.json

@@ -0,0 +1,7 @@
+{
+  "name": "GCAuth",
+  "description": "GCAuth is a plugin that allows you to implement authentication for your server.",
+  "version": "1.0.0",
+  "author": ["ExZork"],
+  "mainClass": "me.exzork.gcauth.GCAuth"
+}