feat(plugins): add Velocity proxy and Fabric/Forge/NeoForge/Paper integration mods

Server-side integration plugins: the Velocity proxy plugin plus Fabric, Forge, NeoForge, and Paper mods with a shared module. Gradle build output is not tracked.

plugins/neoforge/build.gradle

@@ -0,0 +1,41 @@
+plugins {
+    id 'net.neoforged.gradle.userdev' version '7.1.38'
+    id 'java'
+}
+
+group = 'best.lolicon.felis'
+version = '0.1.0'
+
+// NeoForge 20.4 (MC 1.20.4) is a Java-17 line. The Gradle daemon runs on JDK 17,
+// so toolchain 17 resolves to the running JVM with no auto-provisioning.
+java {
+    toolchain.languageVersion = JavaLanguageVersion.of(17)
+}
+
+repositories {
+    mavenCentral()
+    maven {
+        name = 'NeoForged'
+        url = 'https://maven.neoforged.net/releases'
+    }
+}
+
+dependencies {
+    // NeoForge bundles MC at Mojang mappings — same MC class/method names as the
+    // Fabric and Forge modules, so the command handler below is uniform with them.
+    implementation 'net.neoforged:neoforge:20.4.251'
+}
+
+// The zero-dependency link core is compiled in. NeoForge runs Mojang mappings at
+// runtime, so there is no reobf step — the jar straight out of `build` is the deliverable.
+sourceSets {
+    main {
+        java {
+            srcDir '../shared/src/main/java'
+        }
+    }
+}
+
+tasks.withType(JavaCompile).configureEach {
+    options.encoding = 'UTF-8'
+}

plugins/neoforge/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,9 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-bin.zip
+networkTimeout=10000
+retries=0
+retryBackOffMs=500
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

plugins/neoforge/gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015 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.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   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/3d91ce3b8caaf77ad09f381f43615b715b53f72c/platforms/jvm/plugins-application/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
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# 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 "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$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: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$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 "$APP_HOME" )
+
+    JAVACMD=$( 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
+
+
+# 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"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$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 "$JAVACMD" "$@"

plugins/neoforge/gradlew.bat

@@ -0,0 +1,82 @@
+@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
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables, and ensure extensions are enabled
+setlocal EnableExtensions
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+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% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+"%COMSPEC%" /c exit 1
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+"%COMSPEC%" /c exit 1
+
+:execute
+@rem Setup the command line
+
+
+
+@rem Execute Gradle
+@rem endlocal doesn't take effect until after the line is parsed and variables are expanded
+@rem which allows us to clear the local environment before executing the java command
+endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel
+
+:exitWithErrorLevel
+@rem Use "%COMSPEC%" /c exit to allow operators to work properly in scripts
+"%COMSPEC%" /c exit %ERRORLEVEL%

plugins/neoforge/settings.gradle

@@ -0,0 +1,11 @@
+pluginManagement {
+    repositories {
+        gradlePluginPortal()
+        maven {
+            name = 'NeoForged'
+            url = 'https://maven.neoforged.net/releases'
+        }
+    }
+}
+
+rootProject.name = 'felis-neoforge'

plugins/neoforge/src/main/java/best/lolicon/felis/neoforge/FelisNeoForgeMod.java

@@ -0,0 +1,102 @@
+package best.lolicon.felis.neoforge;
+
+import best.lolicon.felis.link.LinkClient;
+import best.lolicon.felis.link.LinkCode;
+import best.lolicon.felis.link.LinkConfig;
+import best.lolicon.felis.link.LinkConfigLoader;
+import best.lolicon.felis.link.LinkException;
+
+import com.mojang.brigadier.CommandDispatcher;
+import com.mojang.brigadier.exceptions.CommandSyntaxException;
+import com.mojang.logging.LogUtils;
+import net.minecraft.commands.CommandSourceStack;
+import net.minecraft.commands.Commands;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.level.ServerPlayer;
+import net.neoforged.bus.api.IEventBus;
+import net.neoforged.bus.api.SubscribeEvent;
+import net.neoforged.fml.common.Mod;
+import net.neoforged.fml.loading.FMLPaths;
+import net.neoforged.neoforge.common.NeoForge;
+import net.neoforged.neoforge.event.RegisterCommandsEvent;
+import org.slf4j.Logger;
+
+import java.io.IOException;
+import java.util.UUID;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * FelisNeoForgeMod is the NeoForge server-side leg of the §10 account-link flow. On
+ * {@link RegisterCommandsEvent} it installs a {@code /link} command that mints a
+ * one-time code from felis-api for the player's already-verified UUID. As on the
+ * other loaders, the HTTP call runs on a daemon I/O thread and the reply is hopped
+ * back onto the server thread; failures collapse to a generic chat line with details
+ * kept to the server log. If config is missing the mod stays loaded but never
+ * registers the command, so the server runs un-crippled.
+ *
+ * <p>NeoForge constructs the mod with the mod event bus injected; the command event
+ * fires on the game bus ({@link NeoForge#EVENT_BUS}), which is what we subscribe to.
+ */
+@Mod("felis_link")
+public final class FelisNeoForgeMod {
+    private static final Logger LOGGER = LogUtils.getLogger();
+
+    private final ExecutorService io = Executors.newSingleThreadExecutor(r -> {
+        Thread t = new Thread(r, "felis-link-io");
+        t.setDaemon(true);
+        return t;
+    });
+    private LinkClient linkClient;
+
+    public FelisNeoForgeMod(IEventBus modEventBus) {
+        try {
+            LinkConfig config = LinkConfigLoader.load(
+                    FMLPaths.CONFIGDIR.get().resolve("felis-link.properties"));
+            this.linkClient = new LinkClient(config);
+            NeoForge.EVENT_BUS.register(this);
+            LOGGER.info("Felis link ready; /link will be registered.");
+        } catch (IOException e) {
+            LOGGER.error("Felis link disabled: {}", e.getMessage());
+        }
+    }
+
+    @SubscribeEvent
+    public void onRegisterCommands(RegisterCommandsEvent event) {
+        register(event.getDispatcher());
+    }
+
+    private void register(CommandDispatcher<CommandSourceStack> dispatcher) {
+        dispatcher.register(Commands.literal("link").executes(ctx -> {
+            CommandSourceStack source = ctx.getSource();
+            ServerPlayer player;
+            try {
+                player = source.getPlayerOrException();
+            } catch (CommandSyntaxException e) {
+                source.sendFailure(Component.literal("/link can only be run by a player."));
+                return 0;
+            }
+            requestAndReply(source.getServer(), player);
+            return 1;
+        }));
+    }
+
+    private void requestAndReply(MinecraftServer server, ServerPlayer player) {
+        UUID uuid = player.getUUID();
+        player.sendSystemMessage(Component.literal("Requesting a link code…"));
+        io.submit(() -> {
+            try {
+                LinkCode code = linkClient.requestCode(uuid);
+                server.execute(() -> player.sendSystemMessage(Component.literal(
+                        "Your link code: " + code.code()
+                        + "  — enter it on the web panel → Account (valid a few minutes).")));
+            } catch (LinkException e) {
+                LOGGER.warn("link code request failed for {} (status={}, code={}): {}",
+                        uuid, e.statusCode(), e.errorCode(), e.getMessage());
+                server.execute(() -> player.sendSystemMessage(Component.literal(
+                        "Couldn't get a link code right now. Please try again in a moment.")));
+            }
+        });
+    }
+}

plugins/neoforge/src/main/resources/META-INF/mods.toml

@@ -0,0 +1,25 @@
+modLoader = "javafml"
+loaderVersion = "[1,)"
+license = "MIT"
+issueTrackerURL = "https://example.invalid/felis"
+
+[[mods]]
+modId = "felis_link"
+version = "0.1.0"
+displayName = "Felis Link"
+description = "In-game /link command: mints a one-time account-link code from felis-api."
+authors = "Felis"
+
+[[dependencies.felis_link]]
+    modId = "neoforge"
+    type = "required"
+    versionRange = "[20.4,)"
+    ordering = "NONE"
+    side = "SERVER"
+
+[[dependencies.felis_link]]
+    modId = "minecraft"
+    type = "required"
+    versionRange = "[1.20.4,1.20.5)"
+    ordering = "NONE"
+    side = "SERVER"

plugins/neoforge/src/main/resources/pack.mcmeta

@@ -0,0 +1,6 @@
+{
+  "pack": {
+    "description": "Felis Link",
+    "pack_format": 22
+  }
+}