MC-Repack

A repacking tool for Minecraft mods to optimize size and loading speed of mods.

Features

• Minifying JSON files, using serde-json
• Optimizing PNG files, using oxipng
• Optimizing TOML files, using toml
• Removing unwanted files – some project files (from Blender, Photoshop, etc.) are mistakenly packed in mods. This operation will detect and remove (ignore while repacking) these files.
• Stripping Unicode BOM
• Removing comment lines in in .cfg files

Comparison table

These mods were tested and repacked by MC-Repack with the following results: | File name | Original | Optimized | |----|----:|----:| | minecolonies-1.19.2-1.0.1247-BETA.jar | 72.8 MB | 65.2 MB | | twilightforest-1.19.3-4.2.1549-universal.jar | 22.5 MB | 22.0 MB | | BloodMagic-1.18.2-3.2.6-41.jar | 13.6 MB | 12.1 MB | | create-1.19.2-0.5.0.i.jar | 13.1 MB | 12.8 MB | | Botania-1.19.2-437-FORGE.jar | 10.9 MB | 10.2 MB |

Installation

Currently the only way to get this app is to use Cargo: sh cargo install mc-repack

If you want to test the latest version directly from this repo: sh cargo install --git https://github.com/szeweq/mc-repack

Usage

After installation, the tool can be used by typing the following command: sh mc-repack <file|directory> When a file path is provided, then MC-Repack will repack the file contents into a $repack.jar. If a path is a directory, then all files inside (non-recursive) will be repacked.

More options are provided by typing mc-repack --help in a shell/terminal.

Why?

MC-Repack is meant to show how many Minecraft mods come with unoptimized files (and I don't mean just pretty-printed JSON files). You will be surprised that in some cases a PNG file's metadata added by Photoshop is much larger than its content.

One other inportant thing is that MC-Repack determines if a file really needs to be compressed. Most PNG files and smaller JSON files will usually be stored uncompressed. This kind of operation saves bytes if a "compressed" form is larger than original. Also, uncompressed data can be loaded faster.

This is a great tool that can be helpful for: - Mod developers – they can provide mods with smaller file sizes, optimized PNGs and correctly formatted JSONs - Players and server owners – optimized and repacked files can speed up Minecraft load time while using less memory.

MC-Repack shows all errors happened during repacking. Most of them are errors that can be simply ignored (like trailing comma at line X column Y).

How to contribute?

The easiest way to contribute is to share this with others on social media.

There is a lot of things that should be fixed or optimized. New feature ideas are welcome, just file an issue.

Can I use it outside Minecraft?

Yes. The tool does not recognize that a .jar file is not a Minecraft mod.

Future plans

• Aggresive mode – minify JavaScript and shader files (potentially breaking debugging).
• Strip unwanted data in JSON files
• Recompress .class files more efficiently