Sample code to read content from a .deb file in Go

ar_and_xz_reader.go

package main

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

	"github.com/blakesmith/ar"
	"github.com/ulikunitz/xz"
)

func main() {

	arFile, err := os.Open("debianfile.deb")
	if err != nil {
		log.Fatal(err)
	}
	defer arFile.Close()

	reader := ar.NewReader(arFile)

	var buf bytes.Buffer
	var buf2 bytes.Buffer

	for {
		header, err := reader.Next()
		if err == io.EOF {
			log.Fatal("The archive did not contain a data.tar.xz file.")
		}
		if err != nil {
			log.Print(err.Error())
		}

		log.Print(header.Name)
		if header.Name == "data.tar.xz" {
			io.Copy(&buf, reader)
			log.Print(buf)
			break
		}
	}

	//// Implementation for gz compression (instead of xz) ////
	// gzf, err := gzip.NewReader(&buf)
	// if err != nil {
	// 	log.Fatal(err)
	// }
	// tarReader := tar.NewReader(gzf)

	xzf, err := xz.NewReader(&buf)
	if err != nil {
		log.Fatal(err)
	}
	tarReader := tar.NewReader(xzf)

	for {
		header, err := tarReader.Next()
		if err == io.EOF {
			log.Fatal("The data.tar archive did not contain a ./requirements.json file.")
		}
		if err != nil {
			log.Fatal(err)
		}
		log.Print(header.Name)

		if header.Name == "./requirements.json" {
			io.Copy(&buf2, tarReader)
			break
		}
	}

	log.Print(string(buf2.Bytes()))
}