minecraft-schemes 0.3.0

Parse Minecraft-relative JSON to structured objects

minecraft-schemes

A Python library for help you to parse Minecraft-relative JSON to structured objects.

Disclaimer: Although the project name contains "minecraft", this project is not supported by Mojang Studios or Microsoft.

Features

Already implemented

• Easy installing
• Open source
• All public APIs are static typed
• Supports parsing various file structures used by Mojang and Minecraft (see below)
• Easy-to-use file structure definitions, powered by attrs
• Rapidly file parsing, powered by cattrs
• Conditional testing for game/command line options and dependency libraries (in client.json)

Not implemented yet (not a complete list)

• Export the data structures to the file
• Parse/build supports for launcher_profiles.json (used by official Minecraft Launcher)
• Search/exactly find a specified version in version_manifest.json
• Game/JVM command line options concatenating and completing

Supported file structures

Click link to see the corresponding documentations.

• version_manifest.json and version_manifest_v2.json [Minecraft Wiki]
  • A JSON file that list Minecraft versions available in the official launcher.
• client.json [Minecraft Wiki]
  • A JSON file that accompanies client.jar in .minecraft/versions/<version> and lists the version's attributes.
  • Usually named <game version>.json.
  • Don't confuse this file with version.json; they are fundamentally different.
• Asset index file [Minecraft Wiki (only Chinese version)]
  • A series of JSON files used to query the hash value of the corresponding hashed resource file based on the resource path, in order to invoke the file.
  • Can be downloaded from the URL pointed in the client.json: [Root Tag] > "assetIndex" > "url"
• version.json [Minecraft Wiki]
  • A JSON file that offers some basic information about the version's attributes.
  • Embedded within client.jar in .minecraft/versions/<version> and server.jar.
  • Don't confuse this file with client.json; they are fundamentally different.
• Mojang Java Runtime index file and manifest files
  • A JSON file that list manifest files of Java Runtime provided by Mojang via their "codename".
  • Not documented by Minecraft Wiki or Mojang, but it is believed to be for the purposes described above.

Install

Install minecraft-schemes using pip:

pip install minecraft-schemes

The release page also provides various versions of wheel files for manual download and installation.

Usage Example

Parse version_manifest.json (download at here)

import mcschemes

with open('version_manifest.json', mode='r') as f:
    version_manifest = mcschemes.load(f, mcschemes.Scheme.VERSION_MANIFEST)

print('Latest release:', version_manifest.latest.release)
print('Latest snapshot:', version_manifest.latest.snapshot)
print('Number of available versions:', len(version_manifest.versions))
for entity in version_manifest.versions:
    if entity.type == 'release':
        print('The ID of the first release version found:', entity.id)
        print('The release time of the first release version found:', entity.releaseTime)
        print('The last update time of the first release version found:', entity.time)
        break

Parse client.json

This example code uses client.json from Minecraft Java Edition 1.21.11, download at here.

import mcschemes

with open('1.21.11.json', mode='r') as f:
    client_manifest_1_21_11 = mcschemes.load(f, mcschemes.Scheme.CLIENT_MANIFEST)

print('Version ID:', client_manifest_1_21_11.id)
# The following field is structured as a member of enum mcschemes.enums.VersionType
print('Version Type:', str(client_manifest_1_21_11.type))
print('Asset version ID:', client_manifest_1_21_11.assetIndex.id)
print('Main class:', client_manifest_1_21_11.mainClass)
print('Release time:', client_manifest_1_21_11.releaseTime)
print('Last update time:', client_manifest_1_21_11.time)
print('Number of dependency libraries:', len(client_manifest_1_21_11.libraries))
client_jar_file_info = client_manifest_1_21_11.downloads.get('client')
if client_jar_file_info:
    print('URL to download the client JAR file:', client_jar_file_info.url)

Parse asset index file

This example code uses the asset index file version 29. You can download it at here.

from pathlib import Path

import mcschemes

with open('29.json', mode='r') as f:
    asset_index = mcschemes.load(f, mcschemes.Scheme.ASSET_INDEX)

print('Number of asset files:', len(asset_index.objects))
asset_file_relative_path = Path('icons/icon_256x256.png')
if asset_file_relative_path in asset_index.objects:
    target_asset_file_info = asset_index.objects[asset_file_relative_path]
    print('Information about asset file {0}: hash={1.hash}, size={1.size}'.format(asset_file_relative_path, target_asset_file_info))

Parse version.json from a client JAR file

This example code uses the client JAR file from Minecraft Java Edition 1.21.11. You can download it in official Minecraft Launcher or at here.

from pathlib import Path

import mcschemes

version_attrs = mcschemes.loadVersionAttrsFromClientJar(Path.home().joinpath('.minecraft/versions/1.21.11/1.21.11.jar'))

print('Unique identifier of this client JAR:', version_attrs.id)
print('User-friendly name of this client JAR:', version_attrs.name)
print('Data version of this client JAR:', version_attrs.world_version)
print('Protocol version of this client JAR:', version_attrs.protocol_version)
print('Build time of this client JAR:', version_attrs.build_time)
if version_attrs.series_id:
    print('Series ID (branch name) of this client JAR:', version_attrs.series_id)

Load client.json, then filter and concatenate command line

This example code uses client.json from Minecraft Java Edition 1.21.11, download at here.

Note: this example only demonstrates basic conditional filtering and concatenation operations, and does not consider the replacement of placeholder parameters (which may be supported in future versions).

import mcschemes
from mcschemes.tools import rules

with open('1.21.11.json', mode='r') as f:
    client_manifest_1_21_11 = mcschemes.load(f, mcschemes.Scheme.CLIENT_MANIFEST)

features: dict[str, bool] = {
    'is_demo_user'         : True,
    'has_custom_resolution': True
}
cmdline: list[str] = ['java']
for jvm_arg_entry in client_manifest_1_21_11.arguments.jvm:
    if rules.isArgumentCanBeAppended(jvm_arg_entry, features=features):
        cmdline.extend(jvm_arg_entry.value)
cmdline.append(client_manifest_1_21_11.mainClass)
for game_arg_entry in client_manifest_1_21_11.arguments.game:
    if rules.isArgumentCanBeAppended(game_arg_entry, features=features):
        cmdline.extend(game_arg_entry.value)
print('Concatenated command line (without placeholder replacements):', cmdline)

History

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

Not planned yet.

[0.3.0] - 2026-01-31

Added

• Scheme: Added support for parsing version information files (the version.json embedded within client.jar).
• Scheme: Added parse support for index file of Mojang Java Runtimes, and file manifest of each java runtime.
• Parsing: Added a dedicated converter class in mcschemes.tools.parser.Converter.DedicatedConverter.
  • This is intended to replace the mcschemes.tools.parser.createConverter().

Backwards-incompatible Changes

• Scheme: mcschemes.assetindex.AssetIndex now use the Path object from the standard library's pathlib module to represent file relative paths in asset index files.

  1. Previously, it will use str to represent file relative paths, so you can access information (e.g. hash, size) by the following way:

     from mcschemes.assetindex import AssetIndex
     
     asset_index: AssetIndex = ...  # Some operations to obtain the json and structure it to the AssetIndex instance
     file_info = asset_index.objects['icons/icon_128x128.png']
     
     [...]  # Do your operations for file_info
     

  2. Now, you need to use a pathlib.Path object as the key to access the corresponding information:

     from pathlib import Path
     from mcschemes.assetindex import AssetIndex
     
     asset_index: AssetIndex = ...  # Some operations to obtain the json and structure it to the AssetIndex instance
     file_info = asset_index.objects[Path('icons/icon_128x128.png')]
     
     [...]  # Do your operations for file_info
     

Deprecations

• Parsing: mcschemes.tools.parser.createConverter() is now marked as deprecated and will be removed in future versions.
  • Now pass a converter class based on cattrs.Converter to the kw-only argument converter_class is no longer determines the type of the returned dedicated converter instance.

Changes

• Project metadata: This version history file has been revised to conform to the format described in Keep a Changelog.
• Project metadata: Fully updated the README file:
  • Added a summary of the main features and benefits.
  • Added a summary of file structures supported by this library.
  • Usage example are now more useful and better represent typical use cases.
• Organizational: Reorganized the project structure:
  • mcschemes.tools.parser now is a package.
    • Sub-package mcschemes.tools.parser.converters is added to contains dedicated converters.
• Typing: typing-extensions was used instead of stdlib typing for better backward-compatibility for type annotation.
• Scheme: Several changes for SHA-1 hexdigest container:
  • The comparison between two mcsehemes.specials.Sha1Sum instances now is based on the case-insensitive form of the hexdigest attribute of both.
  • The exception class mcschemes.specials.ChecksumMismatch is now exposed.
• Parsing: mcschemes.tools.parser.parse() now will check the second argument scheme in more robust way.

Fixed

• Tooling: Fixed a mistake when comparing the OS name in the function mcschemes.tools.rules.isAllow().

[0.2.0] - 2025-12-11

Added

• Project metadata: Added MANIFEST.in for setuptools.
• Scheme: Added a SHA-1 hexdigest container type for sha1/hash fields (un-)structuring. Its definition can be found at: mcschemes.specials.Sha1Sum.
• Tooling: Added some tool functions to calculate a set of rules (iterable of mcschemes.clientmanifest.nodes.RuleEntry instances) means allow or disallow some operation, such as append an argument or download a library file.

Changes

• Project metadata: Declared build backend setuptools into pyproject.toml.
• Project metadata: According to PEP 561, an empty py.typed is added into the root directory of package.
• Project metadata: Corrected the date format for all tier-2 titles in this version history file.
• Organizational: Moved typings.py to the root directory of package.

[0.1.0.post1] - 2025-12-05

Changes

• Project metadata: Added project urls into pyproject.toml.
• Project metadata: Added disclaimer in README.md.

[0.1.0] - 2025-12-04

Added

The initial release.