golang 用tar打包文件或文件夹

打包文件用到了tar包，其中tar包的用法可以参考API

golang提供了个函数用来遍历文件夹 filepath.Walk

函数具体描述如下：

func Walk(root string, walkFn WalkFunc) error  root是用遍历的文件夹

type WalkFunc

type WalkFunc func(path string, info os.FileInfo, err error) error path参数是返回遍历的文件路径和文件信息

在使用中如代码中蓝色部分，通过该方法呢，我们可以对文件和文件夹的操作更加熟悉，其中用到了

os.Create 用来创建文件，返回文件信息和错误信息  func Create(name string) (file *File, err error)

os.Remove 用来删除文件，返回错误信息  func Remove(name string) error

os.Stat   用来返回文件具体信息，返回文件信息和错误信息   func (f *File) Stat() (fi FileInfo, err error)

os.Open   用来打开文件，返回文件信息和错误信息    func Open(name string) (file *File, err error)

io.Copy   复职文件信息到Writer 

func Copy(dst Writer, src Reader) (written int64, err error)func CopyBuffer(dst Writer, src Reader, buf []byte) (written int64, err error)

os.Mkdir 用来创建文件夹，返回错误信息　　func Mkdir(name string, perm FileMode) errorstrings.TrimPrefix(targetpath, directory) 这个方法获取具体的文件路径相对目标文件夹的相对路径，也是在tar包中创建文件夹的相对路径

package main

import (

    "archive/tar"

    "fmt"

    "io"

    "os"

    "path/filepath"

    "strings"

)

/***生成***/

func createTar(filesource, filetarget string, deleteIfExist bool) error {

    //create tar file with targetfile name

    tarfile, err := os.Create(filetarget)

    if err != nil {

        // if file is exist then delete file

        if err == os.ErrExist {

            if err := os.Remove(filetarget); err != nil {

                fmt.Println(err)

                return err

            }

        } else {

            fmt.Println(err)

            return err

        }

    }

    defer tarfile.Close()

    tarwriter := tar.NewWriter(tarfile)

    sfileInfo, err := os.Stat(filesource)

    if err != nil {

        fmt.Println(err)

        return err

    }

    if !sfileInfo.IsDir() {

        return tarFile(filetarget, filesource, sfileInfo, tarwriter)

    } else {

        return tarFolder(filesource, tarwriter)

    }

    return nil

}

func tarFile(directory string, filesource string, sfileInfo os.FileInfo, tarwriter *tar.Writer) error {

    sfile, err := os.Open(filesource)

    if err != nil {

        panic(err)

        return err

    }

    defer sfile.Close()

    header, err := tar.FileInfoHeader(sfileInfo, "")

    if err != nil {

        fmt.Println(err)

        return err

    }

    header.Name = directory

    err = tarwriter.WriteHeader(header)

    if err != nil {

        fmt.Println(err)

        return err

    }

    //  can use buffer to copy the file to tar writer

    //    buf := make([]byte,15)

    //    if _, err = io.CopyBuffer(tarwriter, sfile, buf); err != nil {

    //        panic(err)

    //        return err

    //    }

    if _, err = io.Copy(tarwriter, sfile); err != nil {

        fmt.Println(err)

        panic(err)

        return err

    }

    return nil

}

func tarFolder(directory string, tarwriter *tar.Writer) error {

    var baseFolder string = filepath.Base(directory)

    //fmt.Println(baseFolder)

    return filepath.Walk(directory, func(targetpath string, file os.FileInfo, err error) error {

        //read the file failure

        if file == nil {

            panic(err)

            return err

        }

        if file.IsDir() {

            // information of file or folder

            header, err := tar.FileInfoHeader(file, "")

            if err != nil {

                return err

            }

            header.Name = filepath.Join(baseFolder, strings.TrimPrefix(targetpath, directory))

            fmt.Println(hdr.Name)

            if err = tarwriter.WriteHeader(header); err != nil {

                return err

            }

            os.Mkdir(strings.TrimPrefix(baseFolder, file.Name()), os.ModeDir)

            return nil

        } else {

            //baseFolder is the tar file path

            var fileFolder = filepath.Join(baseFolder, strings.TrimPrefix(targetpath, directory))

            return tarFile(fileFolder, targetpath, file, tarwriter)

        }

    })

}