Add H2 and MySQL support

.github/workflows/build.yml

@@ -0,0 +1,39 @@
+# Automatically build the project and run any configured tests for every push
+# and submitted pull request. This can help catch issues that only occur on
+# certain platforms or Java versions, and provides a first line of defence
+# against bad commits.
+
+name: build
+on: [pull_request, push]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        # Use these Java versions
+        java: [
+          16    # Minimum supported by Minecraft
+        ]
+        # and run on both Linux and Windows
+        os: [ubuntu-20.04, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: checkout repository
+        uses: actions/checkout@v2
+      - name: validate gradle wrapper
+        uses: gradle/wrapper-validation-action@v1
+      - name: setup jdk ${{ matrix.java }}
+        uses: actions/setup-java@v1
+        with:
+          java-version: ${{ matrix.java }}
+      - name: make gradle wrapper executable
+        if: ${{ runner.os != 'Windows' }}
+        run: chmod +x ./gradlew
+      - name: build
+        run: ./gradlew build
+      - name: capture build artifacts
+        if: ${{ runner.os == 'Linux' && matrix.java == '16' }} # Only upload artifacts built from latest java on one OS
+        uses: actions/upload-artifact@v2
+        with:
+          name: Artifacts
+          path: build/libs/

.gitignore

@@ -0,0 +1,33 @@
+# gradle
+
+.gradle/
+build/
+out/
+classes/
+
+# eclipse
+
+*.launch
+
+# idea
+
+.idea/
+*.iml
+*.ipr
+*.iws
+
+# vscode
+
+.settings/
+.vscode/
+bin/
+.classpath
+.project
+
+# macos
+
+*.DS_Store
+
+# fabric
+
+run/

LICENSE

@@ -0,0 +1,165 @@
+                   GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+  This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+  0. Additional Definitions.
+
+  As used herein, "this License" refers to version 3 of the GNU Lesser
+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
+  "The Library" refers to a covered work governed by this License,
+other than an Application or a Combined Work as defined below.
+
+  An "Application" is any work that makes use of an interface provided
+by the Library, but which is not otherwise based on the Library.
+Defining a subclass of a class defined by the Library is deemed a mode
+of using an interface provided by the Library.
+
+  A "Combined Work" is a work produced by combining or linking an
+Application with the Library.  The particular version of the Library
+with which the Combined Work was made is also called the "Linked
+Version".
+
+  The "Minimal Corresponding Source" for a Combined Work means the
+Corresponding Source for the Combined Work, excluding any source code
+for portions of the Combined Work that, considered in isolation, are
+based on the Application, and not on the Linked Version.
+
+  The "Corresponding Application Code" for a Combined Work means the
+object code and/or source code for the Application, including any data
+and utility programs needed for reproducing the Combined Work from the
+Application, but excluding the System Libraries of the Combined Work.
+
+  1. Exception to Section 3 of the GNU GPL.
+
+  You may convey a covered work under sections 3 and 4 of this License
+without being bound by section 3 of the GNU GPL.
+
+  2. Conveying Modified Versions.
+
+  If you modify a copy of the Library, and, in your modifications, a
+facility refers to a function or data to be supplied by an Application
+that uses the facility (other than as an argument passed when the
+facility is invoked), then you may convey a copy of the modified
+version:
+
+   a) under this License, provided that you make a good faith effort to
+   ensure that, in the event an Application does not supply the
+   function or data, the facility still operates, and performs
+   whatever part of its purpose remains meaningful, or
+
+   b) under the GNU GPL, with none of the additional permissions of
+   this License applicable to that copy.
+
+  3. Object Code Incorporating Material from Library Header Files.
+
+  The object code form of an Application may incorporate material from
+a header file that is part of the Library.  You may convey such object
+code under terms of your choice, provided that, if the incorporated
+material is not limited to numerical parameters, data structure
+layouts and accessors, or small macros, inline functions and templates
+(ten or fewer lines in length), you do both of the following:
+
+   a) Give prominent notice with each copy of the object code that the
+   Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the object code with a copy of the GNU GPL and this license
+   document.
+
+  4. Combined Works.
+
+  You may convey a Combined Work under terms of your choice that,
+taken together, effectively do not restrict modification of the
+portions of the Library contained in the Combined Work and reverse
+engineering for debugging such modifications, if you also do each of
+the following:
+
+   a) Give prominent notice with each copy of the Combined Work that
+   the Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the Combined Work with a copy of the GNU GPL and this license
+   document.
+
+   c) For a Combined Work that displays copyright notices during
+   execution, include the copyright notice for the Library among
+   these notices, as well as a reference directing the user to the
+   copies of the GNU GPL and this license document.
+
+   d) Do one of the following:
+
+       0) Convey the Minimal Corresponding Source under the terms of this
+       License, and the Corresponding Application Code in a form
+       suitable for, and under terms that permit, the user to
+       recombine or relink the Application with a modified version of
+       the Linked Version to produce a modified Combined Work, in the
+       manner specified by section 6 of the GNU GPL for conveying
+       Corresponding Source.
+
+       1) Use a suitable shared library mechanism for linking with the
+       Library.  A suitable mechanism is one that (a) uses at run time
+       a copy of the Library already present on the user's computer
+       system, and (b) will operate properly with a modified version
+       of the Library that is interface-compatible with the Linked
+       Version.
+
+   e) Provide Installation Information, but only if you would otherwise
+   be required to provide such information under section 6 of the
+   GNU GPL, and only to the extent that such information is
+   necessary to install and execute a modified version of the
+   Combined Work produced by recombining or relinking the
+   Application with a modified version of the Linked Version. (If
+   you use option 4d0, the Installation Information must accompany
+   the Minimal Corresponding Source and Corresponding Application
+   Code. If you use option 4d1, you must provide the Installation
+   Information in the manner specified by section 6 of the GNU GPL
+   for conveying Corresponding Source.)
+
+  5. Combined Libraries.
+
+  You may place library facilities that are a work based on the
+Library side by side in a single library together with other library
+facilities that are not Applications and are not covered by this
+License, and convey such a combined library under terms of your
+choice, if you do both of the following:
+
+   a) Accompany the combined library with a copy of the same work based
+   on the Library, uncombined with any other library facilities,
+   conveyed under the terms of this License.
+
+   b) Give prominent notice with the combined library that part of it
+   is a work based on the Library, and explaining where to find the
+   accompanying uncombined form of the same work.
+
+  6. Revised Versions of the GNU Lesser General Public License.
+
+  The Free Software Foundation may publish revised and/or new versions
+of the GNU Lesser General Public License from time to time. Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns.
+
+  Each version is given a distinguishing version number. If the
+Library as you received it specifies that a certain numbered version
+of the GNU Lesser General Public License "or any later version"
+applies to it, you have the option of following the terms and
+conditions either of that published version or of any later version
+published by the Free Software Foundation. If the Library as you
+received it does not specify a version number of the GNU Lesser
+General Public License, you may choose any version of the GNU Lesser
+General Public License ever published by the Free Software Foundation.
+
+  If the Library as you received it specifies that a proxy can decide
+whether future versions of the GNU Lesser General Public License shall
+apply, that proxy's public statement of acceptance of any version is
+permanent authorization for you to choose that version for the
+Library.

README.md

@@ -0,0 +1,3 @@
+# Ledger Databases
+
+Adds support for MySQL and H2 databases in Ledger

build.gradle

@@ -0,0 +1,98 @@
+plugins {
+	id 'fabric-loom' version '0.9-SNAPSHOT'
+	id 'maven-publish'
+	id 'org.jetbrains.kotlin.jvm' version "1.5.21"
+}
+
+sourceCompatibility = JavaVersion.VERSION_16
+targetCompatibility = JavaVersion.VERSION_16
+
+archivesBaseName = project.archives_base_name
+version = project.mod_version
+group = project.maven_group
+
+repositories {
+	mavenLocal()
+	maven {
+		url = "https://maven.nucleoid.xyz"
+	}
+	maven {
+		url = "https://oss.sonatype.org/content/repositories/snapshots"
+	}
+}
+
+dependencies {
+	// To change the versions see the gradle.properties file
+	minecraft "com.mojang:minecraft:${project.minecraft_version}"
+	mappings "net.fabricmc:yarn:${project.yarn_mappings}:v2"
+	modImplementation "net.fabricmc:fabric-loader:${project.loader_version}"
+
+	// Fabric API. This is technically optional, but you probably want it anyway.
+	modImplementation "net.fabricmc.fabric-api:fabric-api:${project.fabric_version}"
+
+	// Yes this has to be capitalised
+	modImplementation "com.github.quiltservertools:Ledger:1.0.2"
+
+	modImplementation "net.fabricmc:fabric-language-kotlin:1.6.3+kotlin.1.5.21"
+
+	// H2
+	implementation(include("com.h2database:h2:1.4.200"))
+
+	// MySQL
+	implementation(include('mysql:mysql-connector-java:8.0.19'))
+}
+
+processResources {
+	inputs.property "version", project.version
+
+	filesMatching("fabric.mod.json") {
+		expand "version": project.version
+	}
+}
+
+tasks.withType(JavaCompile).configureEach {
+	// ensure that the encoding is set to UTF-8, no matter what the system default is
+	// this fixes some edge cases with special characters not displaying correctly
+	// see http://yodaconditions.net/blog/fix-for-java-file-encoding-problems-with-gradle.html
+	// If Javadoc is generated, this must be specified in that task too.
+	it.options.encoding = "UTF-8"
+
+	// Minecraft 1.17 (21w19a) upwards uses Java 16.
+	it.options.release = 16
+}
+
+java {
+	// Loom will automatically attach sourcesJar to a RemapSourcesJar task and to the "build" task
+	// if it is present.
+	// If you remove this line, sources will not be generated.
+	withSourcesJar()
+}
+
+jar {
+	from("LICENSE") {
+		rename { "${it}_${project.archivesBaseName}"}
+	}
+}
+
+// configure the maven publication
+publishing {
+	publications {
+		mavenJava(MavenPublication) {
+			// add all the jars that should be included when publishing to maven
+			artifact(remapJar) {
+				builtBy remapJar
+			}
+			artifact(sourcesJar) {
+				builtBy remapSourcesJar
+			}
+		}
+	}
+
+	// See https://docs.gradle.org/current/userguide/publishing_maven.html for information on how to set up publishing.
+	repositories {
+		// Add repositories to publish to here.
+		// Notice: This block does NOT have the same function as the block in the top level.
+		// The repositories here will be used for publishing your artifact, not for
+		// retrieving dependencies.
+	}
+}

gradle.properties

@@ -0,0 +1,16 @@
+# Done to increase the memory available to gradle.
+org.gradle.jvmargs=-Xmx1G
+
+# Fabric Properties
+	# check these on https://fabricmc.net/versions.html
+	minecraft_version=1.17.1
+	yarn_mappings=1.17.1+build.37
+	loader_version=0.11.6
+
+# Mod Properties
+	mod_version = 1.0.0
+	maven_group = net.quiltservertools
+	archives_base_name = ledger-databases
+
+# Dependencies
+	fabric_version=0.37.2+1.17

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 +1,9 @@
+pluginManagement {
+    repositories {
+        maven {
+            name = 'Fabric'
+            url = 'https://maven.fabricmc.net/'
+        }
+        gradlePluginPortal()
+    }
+}

src/main/kotlin/net.quiltservertools.ledger.databases/DatabaseExtensionSpec.kt

@@ -0,0 +1,11 @@
+package net.quiltservertools.ledger.databases
+
+import com.github.quiltservertools.libs.com.uchuhimo.konf.ConfigSpec
+
+object DatabaseExtensionSpec : ConfigSpec("database_extensions") {
+    val h2 by optional(false, "h2")
+    val mySql by optional(false, "mysql")
+    val userName by optional("root", "username")
+    val password by optional("", "password")
+    val url by optional("localhost", "url")
+}

src/main/kotlin/net.quiltservertools.ledger.databases/LedgerDatabaseExtension.kt

@@ -0,0 +1,43 @@
+package net.quiltservertools.ledger.databases
+
+import com.github.quiltservertools.ledger.Ledger
+import com.github.quiltservertools.ledger.api.DatabaseExtension
+import com.github.quiltservertools.libs.com.uchuhimo.konf.ConfigSpec
+import net.minecraft.server.MinecraftServer
+import net.minecraft.util.Identifier
+import net.minecraft.util.WorldSavePath
+import org.jetbrains.exposed.sql.Database
+import kotlin.io.path.pathString
+
+class LedgerDatabaseExtension : DatabaseExtension {
+    override fun getConfigSpecs(): List<ConfigSpec> = listOf(DatabaseExtensionSpec)
+
+    override fun getDatabase(server: MinecraftServer): Database {
+        if (Ledger.config()[DatabaseExtensionSpec.h2]) {
+            return Database.connect("jdbc:h2:${server.getSavePath(WorldSavePath.ROOT).resolve("ledger.h2").toFile()};MODE=MySQL", "org.h2.Driver")
+        } else if (Ledger.config()[DatabaseExtensionSpec.mySql]) {
+            return Database.connect("jdbc:mysql://${Ledger.config()[DatabaseExtensionSpec.url]}", driver = "com.mysql.cj.jdbc.Driver    ",
+                user = Ledger.config()[DatabaseExtensionSpec.userName], password = Ledger.config()[DatabaseExtensionSpec.password])
+        }
+        return sqlite(server)
+    }
+
+    override fun getIdentifier(): Identifier {
+        if (Ledger.config().contains(DatabaseExtensionSpec.h2) && Ledger.config()[DatabaseExtensionSpec.h2]) {
+            return h2Identifier
+        } else if (Ledger.config().contains(DatabaseExtensionSpec.mySql) && Ledger.config()[DatabaseExtensionSpec.mySql]) {
+            return mySqlIdentifier
+
+        }
+        return Ledger.identifier("sqlite")
+    }
+
+    private fun sqlite(server: MinecraftServer) = Database.connect(
+        url = "jdbc:sqlite:${server.getSavePath(WorldSavePath.ROOT).resolve("ledger.sqlite").pathString}",
+    )
+
+    companion object {
+        val h2Identifier = Ledger.identifier("h2_extension")
+        val mySqlIdentifier = Ledger.identifier("mysql_extension")
+    }
+}

src/main/kotlin/net.quiltservertools.ledger.databases/LedgerDatabases.kt

@@ -0,0 +1,10 @@
+package net.quiltservertools.ledger.databases
+
+import com.github.quiltservertools.ledger.api.ExtensionManager
+import net.fabricmc.api.DedicatedServerModInitializer
+
+class LedgerDatabases : DedicatedServerModInitializer {
+    override fun onInitializeServer() {
+        ExtensionManager.registerExtension(LedgerDatabaseExtension())
+    }
+}

src/main/resources/fabric.mod.json

@@ -0,0 +1,35 @@
+{
+  "schemaVersion": 1,
+  "id": "ledger-databases",
+  "version": "${version}",
+
+  "name": "Ledger Databases",
+  "description": "Adds support for H2 and MySQL databases to Ledger",
+  "authors": [
+    "yitzy299"
+  ],
+  "contact": {
+    "homepage": "https://fabricmc.net/",
+    "sources": "https://github.com/FabricMC/fabric-example-mod"
+  },
+
+  "license": "LGPL-3.0",
+
+  "environment": "*",
+  "entrypoints": {
+    "server": [
+      {
+        "value": "net.quiltservertools.ledger.databases.LedgerDatabases"
+      }
+    ]
+  },
+
+  "depends": {
+    "fabricloader": ">=0.11.3",
+    "fabric": "*",
+    "minecraft": "1.17.x",
+    "java": ">=16",
+    "ledger": "*",
+    "fabric-language-kotlin": "*"
+  }
+}