Golang 存档/zip 产生损坏的 zip 文件

Posted 2023-03-06

【中文标题】Golang 存档/zip 产生损坏的 zip 文件

【英文标题】：Golang archive/zip producing corrupt zip files

【发布时间】：2014-07-16 20:59:11

【问题描述】：

我在 Go 中编写了一个小实用程序来压缩文件夹。它似乎在许多情况下都有效，但它时不时会产生一个 zip 文件，当我在解压缩应用程序中打开它时，它会损坏（他们似乎都在抱怨它）。

代码如下：

const (
    singleFileByteLimit = 107374182400 // 1 GB
    chunkSize           = 1024         // 1 KB
)

// ZipFolder zips the given folder to the a zip file
// with the given name
func ZipFolder(srcFolder string, destFile string) error 
    z := &zipper
        srcFolder: srcFolder,
        destFile:  destFile,
    
    return z.zipFolder()


// We need a struct internally because the filepath WalkFunc
// doesn't allow custom params. So we save them here so it can
// access them
type zipper struct 
    srcFolder string
    destFile  string
    writer    *zip.Writer


// internal function to zip a folder
func (z *zipper) zipFolder() error 
    // create zip file
    zipFile, err := os.Create(z.destFile)
    if err != nil 
        return err
    
    defer zipFile.Close()

    // create zip writer
    z.writer = zip.NewWriter(zipFile)

    // traverse the source folder
    err = filepath.Walk(z.srcFolder, z.zipFile)
    if err != nil 
        return nil
    

    // close the zip file
    err = z.writer.Close()
    if err != nil 
        return err
    
    return nil


// internal function to zip a file, called by filepath.Walk on each file
func (z *zipper) zipFile(path string, f os.FileInfo, err error) error 
    // only zip files (directories are created by the files inside of them)
    // TODO allow creating folder when no files are inside
    if !f.IsDir() && f.Size() > 0 
        // open file
        file, err := os.Open(path)
        if err != nil 
            return err
        
        defer file.Close()

        // create new file in zip
        fileName := strings.TrimPrefix(path, z.srcFolder+"/")
        w, err := z.writer.Create(fileName)
        if err != nil 
            return err
        

        // copy contents of the file to the zip writer
        err = copyContents(file, w)
        if err != nil 
            return err
        
    

    return nil


func copyContents(r io.Reader, w io.Writer) error 
    var size int64
    for 
        b := make([]byte, chunkSize)

        // we limit the size to avoid zip bombs
        size += chunkSize
        if size > singleFileByteLimit 
            return errors.New("file too large, please contact us for assitance")
        

        // read chunk into memory
        length, err := r.Read(b)
        if err == io.EOF 
            break
         else if err != nil 
            return err
        
        // write chunk to zip file
        _, err = w.Write(b[:length])
        if err != nil 
            return err
        
    
    return nil

【问题讨论】：

您能否分享一个会产生损坏 zip 的输入？

有一个 Go 包可以做到这一点：github.com/jhoonb/archivex

【参考方案1】：

通读您的代码，我修复了看起来不正确的问题。请尝试以下操作：

const (
    singleFileByteLimit = 107374182400 // 1 GB
    chunkSize           = 4096         // 4 KB
)

func copyContents(r io.Reader, w io.Writer) error 
    var size int64
    b := make([]byte, chunkSize)
    for 
        // we limit the size to avoid zip bombs
        size += chunkSize
        if size > singleFileByteLimit 
            return errors.New("file too large, please contact us for assistance")
        
        // read chunk into memory
        length, err := r.Read(b[:cap(b)])
        if err != nil 
            if err != io.EOF 
                return err
            
            if length == 0 
                break
            
        
        // write chunk to zip file
        _, err = w.Write(b[:length])
        if err != nil 
            return err
        
    
    return nil


// We need a struct internally because the filepath WalkFunc
// doesn't allow custom params. So we save them here so it can
// access them
type zipper struct 
    srcFolder string
    destFile  string
    writer    *zip.Writer


// internal function to zip a file, called by filepath.Walk on each file
func (z *zipper) zipFile(path string, f os.FileInfo, err error) error 
    if err != nil 
        return err
    
    // only zip files (directories are created by the files inside of them)
    // TODO allow creating folder when no files are inside
    if !f.Mode().IsRegular() || f.Size() == 0 
        return nil
    
    // open file
    file, err := os.Open(path)
    if err != nil 
        return err
    
    defer file.Close()
    // create new file in zip
    fileName := strings.TrimPrefix(path, z.srcFolder+"/")
    w, err := z.writer.Create(fileName)
    if err != nil 
        return err
    
    // copy contents of the file to the zip writer
    err = copyContents(file, w)
    if err != nil 
        return err
    
    return nil


// internal function to zip a folder
func (z *zipper) zipFolder() error 
    // create zip file
    zipFile, err := os.Create(z.destFile)
    if err != nil 
        return err
    
    defer zipFile.Close()
    // create zip writer
    z.writer = zip.NewWriter(zipFile)
    err = filepath.Walk(z.srcFolder, z.zipFile)
    if err != nil 
        return nil
    
    // close the zip file
    err = z.writer.Close()
    if err != nil 
        return err
    
    return nil


// ZipFolder zips the given folder to the a zip file
// with the given name
func ZipFolder(srcFolder string, destFile string) error 
    z := &zipper
        srcFolder: srcFolder,
        destFile:  destFile,
    
    return z.zipFolder()

【讨论】：

如果您概述了您更改的内容，对于 OP 和偶然发现这篇文章并遇到类似问题的未来读者来说，这将很有用。

感谢测试。有用。为了缩短代码，copyContents 可以替换为 _,err = io.Copy(w,file) 而不做任何更改