Documentation
¶
Overview ¶
Package zip provides support for reading and writing ZIP archives.
See: http://www.pkware.com/documents/casestudies/APPNOTE.TXT
This package does not support disk spanning.
A note about ZIP64:
To be backwards compatible the FileHeader has both 32 and 64 bit Size fields. The 64 bit fields will always contain the correct value and for normal archives both fields will be the same. For files requiring the ZIP64 format the 32 bit fields will be 0xffffffff and the 64 bit fields must be used instead.
Index ¶
Examples ¶
Constants ¶
const ( Store uint16 = 0 Deflate uint16 = 8 )
Compression methods.
Variables ¶
Functions ¶
func RegisterCompressor ¶
func RegisterCompressor(method uint16, comp Compressor)
RegisterCompressor registers custom compressors for a specified method ID. The common methods Store and Deflate are built in.
func RegisterDecompressor ¶
func RegisterDecompressor(method uint16, d Decompressor)
RegisterDecompressor allows custom decompressors for a specified method ID.
Types ¶
type Compressor ¶
type Compressor func(io.Writer) (io.WriteCloser, error)
A Compressor returns a compressing writer, writing to the provided writer. On Close, any pending data should be flushed.
type Decompressor ¶
type Decompressor func(io.Reader) io.ReadCloser
Decompressor is a function that wraps a Reader with a decompressing Reader. The decompressed ReadCloser is returned to callers who open files from within the archive. These callers are responsible for closing this reader when they're finished reading.
type File ¶
type File struct {
FileHeader
// contains filtered or unexported fields
}
func (*File) DataOffset ¶
DataOffset returns the offset of the file's possibly-compressed data, relative to the beginning of the zip file.
Most callers should instead use Open, which transparently decompresses data and verifies checksums.
type FileHeader ¶
type FileHeader struct {
// Name is the name of the file.
// It must be a relative path: it must not start with a drive
// letter (e.g. C:) or leading slash, and only forward slashes
// are allowed.
Name string
CreatorVersion uint16
ReaderVersion uint16
Flags uint16
Method uint16
ModifiedTime uint16 // MS-DOS time
ModifiedDate uint16 // MS-DOS date
CRC32 uint32
CompressedSize uint32 // Deprecated: Use CompressedSize64 instead.
UncompressedSize uint32 // Deprecated: Use UncompressedSize64 instead.
CompressedSize64 uint64
UncompressedSize64 uint64
Extra []byte
ExternalAttrs uint32 // Meaning depends on CreatorVersion
Comment string
}
FileHeader describes a file within a zip file. See the zip spec for details.
func FileInfoHeader ¶
func FileInfoHeader(fi os.FileInfo) (*FileHeader, error)
FileInfoHeader creates a partially-populated FileHeader from an os.FileInfo. Because os.FileInfo's Name method returns only the base name of the file it describes, it may be necessary to modify the Name field of the returned header to provide the full path name of the file.
func (*FileHeader) FileInfo ¶
func (h *FileHeader) FileInfo() os.FileInfo
FileInfo returns an os.FileInfo for the FileHeader.
func (*FileHeader) ModTime ¶
func (h *FileHeader) ModTime() time.Time
ModTime returns the modification time in UTC. The resolution is 2s.
func (*FileHeader) Mode ¶
func (h *FileHeader) Mode() (mode os.FileMode)
Mode returns the permission and mode bits for the FileHeader.
func (*FileHeader) SetModTime ¶
func (h *FileHeader) SetModTime(t time.Time)
SetModTime sets the ModifiedTime and ModifiedDate fields to the given time in UTC. The resolution is 2s.
func (*FileHeader) SetMode ¶
func (h *FileHeader) SetMode(mode os.FileMode)
SetMode changes the permission and mode bits for the FileHeader.
type ReadCloser ¶
type ReadCloser struct {
Reader
// contains filtered or unexported fields
}
func OpenReader ¶
func OpenReader(name string) (*ReadCloser, error)
OpenReader will open the Zip file specified by name and return a ReadCloser.
func (*ReadCloser) Close ¶
func (rc *ReadCloser) Close() error
Close closes the Zip file, rendering it unusable for I/O.
type Reader ¶
Example ¶
package main
import (
"fmt"
"io"
"log"
"os"
"github.com/klauspost/compress/zip"
)
func main() {
// Open a zip archive for reading.
r, err := zip.OpenReader("testdata/readme.zip")
if err != nil {
log.Fatal(err)
}
defer r.Close()
// Iterate through the files in the archive,
// printing some of their contents.
for _, f := range r.File {
fmt.Printf("Contents of %s:\n", f.Name)
rc, err := f.Open()
if err != nil {
log.Fatal(err)
}
_, err = io.CopyN(os.Stdout, rc, 68)
if err != nil {
log.Fatal(err)
}
rc.Close()
fmt.Println()
}
}
Output: Contents of README: This is the source code repository for the Go programming language.
func NewReader ¶
NewReader returns a new Reader reading from r, which is assumed to have the given size in bytes.
func (*Reader) RegisterDecompressor ¶
func (z *Reader) RegisterDecompressor(method uint16, dcomp Decompressor)
RegisterDecompressor registers or overrides a custom decompressor for a specific method ID. If a decompressor for a given method is not found, Reader will default to looking up the decompressor at the package level.
Must not be called concurrently with Open on any Files in the Reader.
type Writer ¶
type Writer struct {
// contains filtered or unexported fields
}
Writer implements a zip file writer.
Example ¶
package main
import (
"bytes"
"log"
"github.com/klauspost/compress/zip"
)
func main() {
// Create a buffer to write our archive to.
buf := new(bytes.Buffer)
// Create a new zip archive.
w := zip.NewWriter(buf)
// Add some files to the archive.
var files = []struct {
Name, Body string
}{
{"readme.txt", "This archive contains some text files."},
{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
{"todo.txt", "Get animal handling licence.\nWrite more examples."},
}
for _, file := range files {
f, err := w.Create(file.Name)
if err != nil {
log.Fatal(err)
}
_, err = f.Write([]byte(file.Body))
if err != nil {
log.Fatal(err)
}
}
// Make sure to check the error on Close.
err := w.Close()
if err != nil {
log.Fatal(err)
}
}
Output:
func (*Writer) Close ¶
Close finishes writing the zip file by writing the central directory. It does not (and can not) close the underlying writer.
func (*Writer) Create ¶
Create adds a file to the zip file using the provided name. It returns a Writer to which the file contents should be written. The name must be a relative path: it must not start with a drive letter (e.g. C:) or leading slash, and only forward slashes are allowed. The file's contents must be written to the io.Writer before the next call to Create, CreateHeader, or Close.
func (*Writer) CreateHeader ¶
func (w *Writer) CreateHeader(fh *FileHeader) (io.Writer, error)
CreateHeader adds a file to the zip file using the provided FileHeader for the file metadata. It returns a Writer to which the file contents should be written.
The file's contents must be written to the io.Writer before the next call to Create, CreateHeader, or Close. The provided FileHeader fh must not be modified after a call to CreateHeader.
func (*Writer) Flush ¶
Flush flushes any buffered data to the underlying writer. Calling Flush is not normally necessary; calling Close is sufficient.
func (*Writer) RegisterCompressor ¶
func (w *Writer) RegisterCompressor(method uint16, comp Compressor)
RegisterCompressor registers or overrides a custom compressor for a specific method ID. If a compressor for a given method is not found, Writer will default to looking up the compressor at the package level.
Example ¶
package main
import (
"bytes"
"io"
"github.com/klauspost/compress/flate"
"github.com/klauspost/compress/zip"
)
func main() {
// Override the default Deflate compressor with a higher compression
// level.
// Create a buffer to write our archive to.
buf := new(bytes.Buffer)
// Create a new zip archive.
w := zip.NewWriter(buf)
var fw *flate.Writer
// Register the deflator.
w.RegisterCompressor(zip.Deflate, func(out io.Writer) (io.WriteCloser, error) {
var err error
if fw == nil {
// Creating a flate compressor for every file is
// expensive, create one and reuse it.
fw, err = flate.NewWriter(out, flate.BestCompression)
} else {
fw.Reset(out)
}
return fw, err
})
// Proceed to add files to w.
}
Output:
Source Files