New Login Information Saving

Introduction

The new launcher allows users to save more profiles. As you may have suspected, it uses JSON to save your profiles. This file is in .minecraft/launcher_profiles.json. The file is very confusing, since it's saving more things in one. It combines preferences of minecraft launching process and login information, which should be separated in my opinion...

What's in the file

This is the entire file:

{
  "profiles": {
    "Tomsik68": {
      "name": "Tomsik68",
      "javaDir": "/usr/lib/jvm/java-8-openjdk/jre/bin/java",
      "javaArgs": "-Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M",
      "launcherVisibilityOnGameClose": "hide launcher and re-open when game closes"
    },
    "Forge": {
      "name": "Forge",
      "lastVersionId": "1.8-Forge11.14.3.1450"
    }
  },
  "selectedProfile": "Tomsik68",
  "clientToken": "client-token",
  "authenticationDatabase": {
    "UUID": {
      "displayName": "Tomsik68",
      "userProperties": [
        {
          "name": "twitch_access_token",
          "value": "my_twitch_token"
        }
      ],
      "accessToken": "my_session_id",
      "userid": "my_user_id",
      "uuid": "UUID",
      "username": "tomsik68@gmail.com"
    }
  },
  "selectedUser": "UUID",
  "launcherVersion": {
    "name": "1.6.13",
    "format": 17
  }
}

---

Authentication database

Let's get straight to authentication database, because that's the only section which stores login information.

Let's start by JSON example:

"player-uuid": {
    "username": "tomsik68@gmail.com",
    "accessToken": "accessToken",
    "userid": "user-id",
    "uuid": "player-uuid",
    "displayName": "Tomsik68"
}

I had to hide the real values, because exposing them is dangerous :)

Let's make a table!(yeah, markdown...). Value type for all these nodes is string, so I'm not putting it down...

Node name	Description
username	Username of mojang/minecraft account
accessToken	Lastly used session ID
userid	Usage unknown, probably mojang account ID
uuid	UUID of player(minecraft-related)
displayName	This is how you see the authentication profile in launcher