是否可以在golang中提取tar.xz包？

Question

Is it possible to extract a tar.xz package in golang? My understanding is it's possible to use the library for tar and sending it to an xz go library.

Answer 1

I recently created an XZ decompression package so it is now possible to extract a tar.xz using only Go code.

The following code extracts the file myfile.tar.xz to the current directory:

package main

import (
    "archive/tar"
    "fmt"
    "io"
    "log"
    "os"

    "github.com/xi2/xz"
)

func main() {
    // Open a file
    f, err := os.Open("myfile.tar.xz")
    if err != nil {
        log.Fatal(err)
    }
    // Create an xz Reader
    r, err := xz.NewReader(f, 0)
    if err != nil {
        log.Fatal(err)
    }
    // Create a tar Reader
    tr := tar.NewReader(r)
    // Iterate through the files in the archive.
    for {
        hdr, err := tr.Next()
        if err == io.EOF {
            // end of tar archive
            break
        }
        if err != nil {
            log.Fatal(err)
        }
        switch hdr.Typeflag {
        case tar.TypeDir:
            // create a directory
            fmt.Println("creating:   " + hdr.Name)
            err = os.MkdirAll(hdr.Name, 0777)
            if err != nil {
                log.Fatal(err)
            }
        case tar.TypeReg, tar.TypeRegA:
            // write a file
            fmt.Println("extracting: " + hdr.Name)
            w, err := os.Create(hdr.Name)
            if err != nil {
                log.Fatal(err)
            }
            _, err = io.Copy(w, tr)
            if err != nil {
                log.Fatal(err)
            }
            w.Close()
        }
    }
    f.Close()
}

Answer 2

http://golang.org/pkg/archive/tar/#example_

also you can do

import "os/exec"

cmd := exec.Command("tar", "-x", "/your/archive.tar.xz")
err := cmd.Run()

Answer 3

There is no Lempel-Ziv-Markow encoder or decoder in the Go standard library. If you are allowed to assume that the platform your code runs on provides the xz utility, you could use stub functions like these:

import "os/exec"

// decompress xz compressed data stream r.
func UnxzReader(r io.Reader) (io.ReadCloser, error) {
    unxz := exec.Command("xz", "-d")
    unxz.Stdin = r
    out, err := unxz.StdoutPipe()
    if err != nil {
        return nil, err
    }

    err = unxz.Start()
    if err != nil {
        return nil, err
    }

    // we are not interested in the exit status, but we should really collect
    // that zombie process
    go unxz.Wait()

    return out, nil
}