golang 用tar打包文件或文件夾

打包文件用到了tar包，其中tar包的用法能夠參考API 

golang提供了個函數用來遍歷文件夾 filepath.Walk

函數具體描述以下：

func Walk(root string, walkFn WalkFunc) error  root是用遍歷的文件夾

type WalkFunc

type WalkFunc func(path string, info os.FileInfo, err error) error path參數是返回遍歷的文件路徑和文件信息

在使用中如代碼中藍色部分，經過該方法呢，咱們能夠對文件和文件夾的操做更加熟悉，其中用到了

os.Create 用來建立文件，返回文件信息和錯誤信息  func Create(name string) (file *File, err error)

os.Remove 用來刪除文件，返回錯誤信息  func Remove(name string) error

os.Stat   用來返回文件具體信息，返回文件信息和錯誤信息   func (f *File) Stat() (fi FileInfo, err error)

os.Open   用來打開文件，返回文件信息和錯誤信息    func Open(name string) (file *File, err error)

io.Copy   復職文件信息到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 用來建立文件夾，返回錯誤信息　　func Mkdir(name string, perm FileMode) error

strings.TrimPrefix(targetpath, directory) 這個方法獲取具體的文件路徑相對目標文件夾的相對路徑，也是在tar包中建立文件夾的相對路徑

 

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)

        }

    })

}