Cauldron Mod Manager

This Documentation is correct for version 0.3.0 of CauldronModManager

What does this do?

Cauldron Mod Manager (CMM) is a Node.js modpack manager for Minecraft. It can:

• Create packs from scratch, resolving mods from CurseForge and Modrinth for a Minecraft version and loader
• Import CurseForge (.zip) and Modrinth (.mrpack) modpacks
• Add / remove mods in a pack, automatically adding required dependencies
• Install a pack into a game folder, downloading every mod and verifying its checksum

Packs are stored in CMM’s own pack format, which only holds metadata and hashes, so they are small and easy to share. Mods are downloaded when the pack is installed.

CMM is used by CauldronCLI but works in any Node.js project.

License Information

This project is licensed under GPL 3.0 so please make sure that your project follows the license guidelines.

Setup

To Install the package, run the following command

npm i @jackcooperdev/cmm

Requirements:

• Node.js 20.12 or newer
• CommonJS (require)
• Internet access to the following hosts

Host	Used for
api.curseforge.com	CurseForge mod information
cf.polymc.org	CurseForge API key
api.modrinth.com	Modrinth mod information
resources.cauldronmc.com	Recommended loader versions
edge.forgecdn.net	CurseForge downloads
cdn.modrinth.com	Modrinth downloads

Using Cauldron Mod Manager

CMM is split into two exports.

Name	Import	Description
Pack	@jackcooperdev/cmm/pack	Create, import and edit packs
Bootstrap	@jackcooperdev/cmm/bootstrap	Install a pack into a game folder

Quick Start

const { createPack } = require('@jackcooperdev/cmm/pack');
const { installMods } = require('@jackcooperdev/cmm/bootstrap');

// 1. Create a pack in ./packs/my-pack
const pack = await createPack({
    name: 'my-pack',
    author: 'Me',
    minecraftVersion: '1.20.1',
    loader: 'fabric',
    mods: [
        { source: 'mr', slug: 'sodium' },
        { source: 'cf', slug: 'jei' },
    ],
}, './packs');

// 2. Install it into a game folder
await installMods('./packs/my-pack', './instances/my-pack');

The game folder can then be used as the game_directory override when launching with Cauldron Engine.

Pack Format

A pack is a folder of small JSON files rather than the mod jars themselves.

my-pack/
├── pack.json            # Pack information
├── index.json           # Every file in the pack and its hash
├── mods/
│   ├── sodium-cmm.json  # One metadata file per mod
│   └── jei-cmm.json
├── resourcepacks/
├── shaderpacks/
└── config/...           # Override files (imported packs only)

pack.json

{
  "name": "my-pack",
  "author": "Me",
  "pack-format": "cmm-1.0.0",
  "index": { "file": "index.json", "hash-format": "sha256", "hash": "..." },
  "versions": {
    "minecraft": "1.20.1",
    "loader": { "type": "fabric", "version": "0.15.7" }
  }
}

Imported packs also include sourceHash, the SHA-256 of the archive they were imported from.

index.json

[
  { "file": "mods/sodium-cmm.json", "metafile": true, "hash": "..." },
  { "file": "config/sodium-options.json", "hash": "..." }
]

Entries with metafile: true are mod metadata files. Other entries are override files that are copied into the game folder as-is.

Mod metadata (<slug>-cmm.json)

{
  "name": "Sodium",
  "filename": "sodium-fabric-0.5.8+mc1.20.1.jar",
  "slug": "sodium",
  "side": "both",
  "download": { "hash-format": "sha1", "hash": "...", "mode": "metadata:modrinth" },
  "class": "mod",
  "fileId": "...",
  "projectId": "..."
}

download.mode is metadata:curseforge or metadata:modrinth and decides where the file is downloaded from. Files are placed in a folder based on their type (mods, resourcepacks or shaderpacks).