MC-Repack

An experimental 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

There are other, less important functions like stripping Unicode BOM and removing comment lines in .cfg files.

Comparison table

These mods were tested and repacked by MC-Repack with the following results: | File name | Before | After | |----|----:|----:| | 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 | | create-1.19.2-0.5.0.i.jar | 13.1 MB | 12.8 MB |

Usage

Currently the only way to get this app is to use Cargo: sh cargo install --git https://github.com/szeweq/mc-repack

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.

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).
• Remove 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.