zip

package module
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 Go to latest Published: May 7, 2026 License: BSD-3-Clause Imports: 38 Imported by: 0

README

Go Advanced ZIP Library

Go Reference

This project is a highly optimized and advanced drop-in replacement for the Go standard library archive/zip.

It combines the stability of the standard library with the best open-source ZIP processing features available in the Go ecosystem into one single, powerful package.

Features

  1. Drop-in Compatibility: 100% compatible with the archive/zip API. You can safely replace your archive/zip imports with github.com/unxed/zip.
  2. WinZip AES Encryption (AE-2): Full support for reading and writing AES-encrypted archives (128, 192, and 256-bit).
  3. Central Directory Encryption (CDE): The ability to encrypt the archive's metadata (filenames, sizes, etc.), making the list of files invisible without a password.
  4. Deflate64 Support: Built-in decoder for the Deflate64 (Method 9) format, commonly used by Windows' built-in archiver for large files.
  5. High Performance: Uses the blazing-fast klauspost/compress library for DEFLATE and adds native Zstandard (ZSTD) support.
  6. Multithreaded Archiving & Extraction: Concurrent archiver and extractor (adapted from fastzip) that processes multiple files in parallel.
  7. Cross-Platform Metadata:
    • Unix: Automatic preservation of UID/GID and extended timestamps.
    • Windows: Support for reading and writing NTFS Security Descriptors (ACLs).
  8. In-Place Archiving (Updater): Modify existing ZIP files (append/overwrite) without full re-compression.
  9. Legacy Codepage Auto-Detection: Advanced encoding detection from 7-zip / far2l to fix "mojibake" in filenames from legacy archives.

Usage

1. Standard Reader / Writer
import "github.com/unxed/zip"

// Use exactly like the standard library
r, err := zip.OpenReader("archive.zip")
// ...
2. High-Speed Multithreaded Archiving
w, _ := os.Create("archive.zip")
defer w.Close()

// Create archiver with concurrency
archiver, _ := zip.NewArchiver(w, "/path/to/source", zip.WithArchiverConcurrency(8))
defer archiver.Close()

// Map your files
files := make(map[string]os.FileInfo)
filepath.Walk("/path/to/source", func(p string, info os.FileInfo, err error) error {
	files[p] = info
	return nil
})

// Archive concurrently!
archiver.Archive(context.Background(), files)
3. In-Place Archive Update
f, _ := os.OpenFile("archive.zip", os.O_RDWR, 0)
defer f.Close()

updater, _ := zip.NewUpdater(f)
defer updater.Close()

// Overwrite an existing file natively
w, _ := updater.Append("config.json", zip.APPEND_MODE_OVERWRITE)
w.Write([]byte(`{"updated": true}`))

### 4. Create an Invisible (CDE) AES-256 Archive

```go
w, _ := os.Create("stealth.zip")
zw := zip.NewWriter(w)

// Encrypt the list of files itself!
zw.SetEncryptCentralDirectory(true, "master-password")

fh := &zip.FileHeader{Name: "secret.txt", Password: "master-password"}
f, _ := zw.CreateHeader(fh)
f.Write([]byte("top secret data"))
zw.Close()

License

This project is released under the BSD-3-Clause License. See also CREDITS.md.

Documentation

Index

Constants

View Source 
const (
	Store     uint16 = 0 // no compression
	Deflate   uint16 = 8 // DEFLATE compressed
	Deflate64 uint16 = 9
	BZIP2     uint16 = 12
	LZMA      uint16 = 14
	ZSTD      uint16 = 93 // Zstandard compressed
)

Compression methods.

Variables

View Source 
var (
	OEMDecoder    *encoding.Decoder = charmap.CodePage437.NewDecoder()
	ANSIDecoder   *encoding.Decoder = charmap.Windows1252.NewDecoder()
	SystemDecoder *encoding.Decoder = charmap.CodePage437.NewDecoder()
)

Legacy Decoders configuration. They are automatically initialized based on the system locale during init(). You can override them manually if you need strict enforcement.

View Source 
var (
	ErrFormat       = errors.New("zip: not a valid zip file")
	ErrAlgorithm    = errors.New("zip: unsupported compression algorithm")
	ErrChecksum     = errors.New("zip: checksum error")
	ErrInsecurePath = errors.New("zip: insecure file path")
)
View Source 
var ConfigIncludePlatformMetadata = false

ConfigIncludePlatformMetadata defines if FileInfoHeader should automatically include OS-specific metadata (like UID/GID on Unix). Disabled by default to ensure archive portability.

View Source 
var ErrMinConcurrency = errors.New("concurrency must be at least 1")

Functions

func RegisterCompressor 

func RegisterCompressor(method uint16, comp Compressor)

func RegisterDecompressor 

func RegisterDecompressor(method uint16, dcomp Decompressor)

Types

type AppendMode 

type AppendMode int

AppendMode specifies the way to append new file to existing zip archive. 

const (
	// APPEND_MODE_OVERWRITE removes the existing file data and append the new
	// data to the end of the zip archive.
	APPEND_MODE_OVERWRITE AppendMode = iota

	// APPEND_MODE_KEEP_ORIGINAL will keep the original file data and only
	// write the new file data at the end of the existing zip archive file.
	// This mode will keep multiple file with same name into one archive file.
	APPEND_MODE_KEEP_ORIGINAL
)

type Archiver 

type Archiver struct {
	// contains filtered or unexported fields
}

func NewArchiver 

func NewArchiver(w io.Writer, chroot string, opts ...ArchiverOption) (*Archiver, error)

func (*Archiver) Archive 

func (a *Archiver) Archive(ctx context.Context, files map[string]os.FileInfo) (err error)

func (*Archiver) Close 

func (a *Archiver) Close() error

func (*Archiver) Written 

func (a *Archiver) Written() (bytes, entries int64)

type ArchiverOption 

type ArchiverOption func(*archiverOptions) error

func WithArchiverBufferSize 

func WithArchiverBufferSize(n int) ArchiverOption

func WithArchiverConcurrency 

func WithArchiverConcurrency(n int) ArchiverOption

func WithArchiverMethod 

func WithArchiverMethod(method uint16) ArchiverOption

func WithArchiverOffset 

func WithArchiverOffset(n int64) ArchiverOption

func WithArchiverPlatformMetadata 

func WithArchiverPlatformMetadata(enable bool) ArchiverOption

WithArchiverPlatformMetadata enables inclusion of local OS metadata (UID/GID) for this archiver instance.

func WithStageDirectory 

func WithStageDirectory(dir string) ArchiverOption

type Compressor 

type Compressor func(w io.Writer) (io.WriteCloser, error)

type Decompressor 

type Decompressor func(r io.Reader) io.ReadCloser

type Directory 

type Directory struct {
	FileHeader
	// contains filtered or unexported fields
}

func (*Directory) HeaderOffset 

func (d *Directory) HeaderOffset() int64

type Extractor 

type Extractor struct {
	// contains filtered or unexported fields
}

func NewExtractor 

func NewExtractor(filename, chroot string, opts ...ExtractorOption) (*Extractor, error)

func NewExtractorFromReader 

func NewExtractorFromReader(r io.ReaderAt, size int64, chroot string, opts ...ExtractorOption) (*Extractor, error)

func (*Extractor) Close 

func (e *Extractor) Close() error

func (*Extractor) Extract 

func (e *Extractor) Extract(ctx context.Context) (err error)

func (*Extractor) Files 

func (e *Extractor) Files() []*File

func (*Extractor) Written 

func (e *Extractor) Written() (bytes, entries int64)

type ExtractorOption 

type ExtractorOption func(*extractorOptions) error

func WithExtractorChownErrorHandler 

func WithExtractorChownErrorHandler(fn func(name string, err error) error) ExtractorOption

func WithExtractorConcurrency 

func WithExtractorConcurrency(n int) ExtractorOption

func WithExtractorMaxFileSize 

func WithExtractorMaxFileSize(n int64) ExtractorOption

func WithExtractorMaxRatio 

func WithExtractorMaxRatio(n int64) ExtractorOption

type File 

type File struct {
	FileHeader
	// contains filtered or unexported fields
}

func (*File) DataOffset 

func (f *File) DataOffset() (offset int64, err error)

func (*File) Open 

func (f *File) Open() (io.ReadCloser, error)

func (*File) OpenRaw 

func (f *File) OpenRaw() (io.Reader, error)

type FileHeader 

type FileHeader struct {
	Name               string
	Comment            string
	NonUTF8            bool // If set, disables automatic UTF-8 flag encoding
	CreatorVersion     uint16
	ReaderVersion      uint16
	Flags              uint16
	Method             uint16
	Modified           time.Time
	Accessed           time.Time
	Created            time.Time
	ModifiedTime       uint16 // Deprecated
	ModifiedDate       uint16 // Deprecated
	CRC32              uint32
	CompressedSize     uint32 // Deprecated: Use CompressedSize64
	UncompressedSize   uint32 // Deprecated: Use UncompressedSize64
	CompressedSize64   uint64
	UncompressedSize64 uint64
	Extra              []byte
	ExternalAttrs      uint32
	// UNIX attributes
	Uid      int
	Gid      int
	OwnerSet bool
	// NTFS Attributes
	Acl []byte // Windows Security Descriptor (ACL)

	// WinZip AES encryption
	Password    string
	AESStrength byte // 1 = 128, 2 = 192, 3 = 256. Defaults to 3 (AES-256) if Password != ""
}

FileHeader describes a file within a ZIP file.

func FileInfoHeader 

func FileInfoHeader(fi fs.FileInfo) (*FileHeader, error)

func (*FileHeader) FileInfo 

func (h *FileHeader) FileInfo() fs.FileInfo

func (*FileHeader) IsEncrypted 

func (h *FileHeader) IsEncrypted() bool

func (*FileHeader) ModTime 

func (h *FileHeader) ModTime() time.Time

func (*FileHeader) Mode 

func (h *FileHeader) Mode() (mode fs.FileMode)

func (*FileHeader) SetModTime 

func (h *FileHeader) SetModTime(t time.Time)

func (*FileHeader) SetMode 

func (h *FileHeader) SetMode(mode fs.FileMode)

type ReadCloser 

type ReadCloser struct {
	Reader
	// contains filtered or unexported fields
}

func OpenReader 

func OpenReader(name string) (*ReadCloser, error)

func (*ReadCloser) Close 

func (rc *ReadCloser) Close() error

type Reader 

type Reader struct {
	File    []*File
	Comment string
	// contains filtered or unexported fields
}

func NewReader 

func NewReader(r io.ReaderAt, size int64) (*Reader, error)

func (*Reader) Open 

func (r *Reader) Open(name string) (fs.File, error)

func (*Reader) RegisterDecompressor 

func (r *Reader) RegisterDecompressor(method uint16, dcomp Decompressor)

func (*Reader) SetPassword 

func (r *Reader) SetPassword(password string)

type Updater 

type Updater struct {
	// contains filtered or unexported fields
}

Updater allows to modify & append files into an existing zip archive without decompress the whole file.

func NewUpdater 

func NewUpdater(rws io.ReadWriteSeeker) (*Updater, error)

NewUpdater returns a new Updater from io.ReadWriteSeeker, which is assumed to have the given size in bytes.

func (*Updater) Append 

func (u *Updater) Append(name string, mode AppendMode) (io.Writer, error)

func (*Updater) AppendHeader 

func (u *Updater) AppendHeader(fh *FileHeader, mode AppendMode) (io.Writer, error)

func (*Updater) Close 

func (u *Updater) Close() error

func (*Updater) Entries 

func (u *Updater) Entries() []*FileHeader

func (*Updater) GetComment 

func (u *Updater) GetComment() string

func (*Updater) RemoveFile 

func (u *Updater) RemoveFile(dirIndex int) (int64, error)

func (*Updater) SetComment 

func (u *Updater) SetComment(comment string) error

type Writer 

type Writer struct {
	// contains filtered or unexported fields
}

func NewWriter 

func NewWriter(w io.Writer) *Writer

func (*Writer) AddFS 

func (w *Writer) AddFS(fsys fs.FS) error

func (*Writer) Close 

func (w *Writer) Close() error

func (*Writer) Copy 

func (w *Writer) Copy(f *File) error

func (*Writer) Create 

func (w *Writer) Create(name string) (io.Writer, error)

func (*Writer) CreateHeader 

func (w *Writer) CreateHeader(fh *FileHeader) (io.Writer, error)

func (*Writer) CreateRaw 

func (w *Writer) CreateRaw(fh *FileHeader) (io.Writer, error)

func (*Writer) Flush 

func (w *Writer) Flush() error

func (*Writer) RegisterCompressor 

func (w *Writer) RegisterCompressor(method uint16, comp Compressor)

func (*Writer) SetComment 

func (w *Writer) SetComment(comment string) error

func (*Writer) SetEncryptCentralDirectory 

func (w *Writer) SetEncryptCentralDirectory(enable bool, password string)

SetEncryptCentralDirectory enables encryption of the central directory records. This hides file names and metadata from unauthorized users. Requires a password to be set.

func (*Writer) SetOffset 

func (w *Writer) SetOffset(n int64)

Source Files

View all Source files

Directories

Path Synopsis
internal
filepool

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