boar

boar will sniff any archive, and maybe even let you extract it.

Format Support

Format	Extractor	Native Dependency
.zip	zipextractor (via savior)	None (pure Go)
.tar	tarextractor (via savior)	None (pure Go)
.tar.gz	tarextractor + gzipsource	None (pure Go)
.tar.bz2	tarextractor + bzip2source	None (pure Go)
.tar.xz	tarextractor + xzsource	Requires 7-zip libs
.rar	rarextractor (via dmcunrar-go)	dmc_unrar (C library)
.7z	szextractor (via sevenzip-go)	7z.so + libc7zip.so
.exe (self-extracting)	szextractor	7z.so + libc7zip.so

Formats with native dependencies will fail to extract if the required libraries are not available. The pure Go extractors work without any additional dependencies.

Native library installation

The szextractor package can automatically download the required 7-zip native libraries at runtime from broth.itch.zone/libc7zip, itch.io's binary distribution service. When szextractor.EnsureDeps is called, it checks for the required libraries next to the executable and fetches them from broth if they are missing or have mismatched hashes.

By default, library versions and hashes are pinned in the hardcoded formulas under szextractor/formulas/. You can override this to fetch from a specific broth channel (e.g. head for the latest build) using szextractor.SetDepChannel("head"), which skips hash verification and fetches from broth.itch.zone/libc7zip/{os}-{arch}-{channel}/LATEST/archive.zip. The szextractor.InstallDeps function can be used to force a fresh download regardless of what is already on disk.

Set the environment variable BUTLER_NO_DEPS=1 to disable automatic dependency fetching entirely.

Dependencies

• https://github.com/itchio/savior - for resumable extraction (zip, tar)
• https://github.com/itchio/arkive - fork of Go's archive/zip and archive/tar with resume support (used by savior)
• https://github.com/itchio/dash - for file sniffing
• https://github.com/itchio/sevenzip-go - for 7z and self-extracting archives
• https://github.com/itchio/dmcunrar-go - for RAR archives

License

boar's code itself is under MIT License, see LICENSE for details.

However:

• szextractor uses 7-zip, which is licensed under LGPL and BSD 3-clause, see https://www.7-zip.org/
• rarextractor uses dmc_unrar, which has LGPL and BSD clauses, see https://github.com/DrMcCoy/dmc_unrar