minecraft-launcher-core v3.18.1

Project rewrite coming soon™

MCLC (Minecraft Launcher Core) is a NodeJS solution for launching modded and vanilla Minecraft without having to download and format everything yourself. Basically a core for your Electron or script based launchers.

Getting support

I've created a Discord server for anyone who needs to get in contact with me or get help!

Installing

npm i minecraft-launcher-core

Standard Example

const { Client, Authenticator } = require('minecraft-launcher-core');
const launcher = new Client();

let opts = {
    // For production launchers, I recommend not passing 
    // the getAuth function through the authorization field and instead
    // handling authentication outside before you initialize
    // MCLC so you can handle auth based errors and validation!
    authorization: Authenticator.getAuth("username", "password"),
    root: "./minecraft",
    version: {
        number: "1.14",
        type: "release"
    },
    memory: {
        max: "6G",
        min: "4G"
    }
}

launcher.launch(opts);

launcher.on('debug', (e) => console.log(e));
launcher.on('data', (e) => console.log(e));

Documentation

Client Functions

launch

IF YOU'RE NEW TO MCLC, LET IT HANDLE EVERYTHING! DO NOT USE OVERRIDES!

let opts = {
   otherOps...,
   overrides: {
       gameDirectory: '', // where the game process generates folders like saves and resource packs.
       minecraftJar: '',
       versionName: '', // replaces the value after the version flag.
       versionJson: '',
       directory: '', // where the Minecraft jar and version json are located.
       natives: '', // native directory path.
       assetRoot: '',
       assetIndex: '',
       libraryRoot: '',
       cwd: '', // working directory of the java process.
       detached: true, // whether or not the client is detached from the parent / launcher.
       classes: [], // all class paths are required if you use this.
       minArgs: 11, // The amount of launch arguments specified in the version file before it adds the default again
       maxSockets: 2, // max sockets for downloadAsync.
       // The following is for launcher developers located in countries that have the Minecraft and Forge resource servers
       // blocked for what ever reason. They obviously need to mirror the formatting of the original JSONs / file structures.
       url: {
           meta: 'https://launchermeta.mojang.com', // List of versions.
           resource: 'https://resources.download.minecraft.net', // Minecraft resources.
           mavenForge: 'http://files.minecraftforge.net/maven/', // Forge resources.
           defaultRepoForge: 'https://libraries.minecraft.net/', // for Forge only, you need to redefine the library url
                                                                // in the version json.
           fallbackMaven: 'https://search.maven.org/remotecontent?filepath='
       },
       // The following is options for which version of ForgeWrapper MCLC uses. This allows us to launch modern Forge.
       fw: {
        baseUrl: 'https://github.com/ZekerZhayard/ForgeWrapper/releases/download/',
        version: '1.5.1',
        sh1: '90104e9aaa8fbedf6c3d1f6d0b90cabce080b5a9',
        size: 29892,
      },
      logj4ConfigurationFile: ''
   }
}

Notes

Custom

If you are loading up a client outside of vanilla Minecraft or Forge (Optifine and for an example), you'll need to download the needed files yourself if you don't provide downloads url downloads like Forge and Fabric. If no version jar is specified, MCLC will default back to the normal MC jar so mods like Fabric work.

Authentication (Deprecated)

MCLC's authenticator module does not support Microsoft authentication. You will need to use a library like MSMC. If you want to create your own solution, the following is the authorization JSON object format.

{
    access_token: '',
    client_token: '',
    uuid: '',
    name: '',
    user_properties: '{}',
    meta: {
        type: 'mojang' || 'msa',
        demo: true || false, // Demo can also be specified by adding 'is_demo_user' to the options.feature array 
        // properties only exists for specific Minecraft versions.
        xuid: '',
        clientId: ''
    }
}

Authenticator Functions

getAuth

validate

refreshAuth

invalidate

signOut

changeApiUrl

Events

What should it look like running from console?

The pid is printed in console after the process is launched.

Contributors

These are the people that helped out that aren't listed here!

• Pyker - Forge dependency parsing.
• Khionu - Research on how Minecraft'snatives are handled.
• Coding-Kiwi - Pointed out I didn't pass clientToken in initial authentication function.
• maxbsoft - Pointed out that a certain JVM option causes OSX Minecraft to bug out.
• Noé - Pointed out launch args weren't being passed for Forge 1.13+.