beta.blog

The following code is a pure Go unrar implementation. It supports multi‑volume archives, compressed archives and takes a password (or empty string “” if no password is required). It was tested with RAR 6.x archives but supports older versions as well.

Also, during unpacking, the folder structure of the archive is retained.

package main

import (
	"io"
	"log"
	"os"
	"path/filepath"

	"github.com/nwaples/rardecode"
)

func extractRAR(srcDir, destDir, password string) error {
	rc, err := rardecode.OpenReader(srcDir, password)
	if err != nil {
		return err
	}
	defer rc.Close()

	rr := &rc.Reader
	for {
		hdr, err := rr.Next()
		if err == io.EOF {
			return nil
		} else if err != nil {
			return err
		}

		outPath := filepath.Join(destDir, hdr.Name)
		if hdr.IsDir {
			if err := os.MkdirAll(outPath, hdr.Mode()); err != nil {
				return err
			}
			continue
		}

		if err := os.MkdirAll(filepath.Dir(outPath), 0755); err != nil {
			return err
		}

		f, err := os.OpenFile(outPath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, hdr.Mode())
		if err != nil {
			return err
		}
		if _, err := io.Copy(f, rr); err != nil {
			f.Close()
			return err
		}
		f.Close()
	}
}

func main() {
	if err := extractRAR("archive.rar", "./output", "mySecretPassword"); err != nil {
		log.Fatal(err)
	}
	log.Println("Done!")
}