Golang : Zip file
Go's standard library provides support for several archive file formats. Zip format is the most common standard of compressing file. It is easy to create/compress zip file in Go.
The package you need to import is
archive/zip
and below is a simple Go program to compress file.
NOTE : The default compression level is 0(store), you have to change the compression algorithm to deflate(number 8). Otherwise, you will find that the created zip file size will be slightly larger!
go-zip.go
package main
import (
"archive/zip"
"flag"
"fmt"
"io"
"os"
)
// use RegisterCompressor, if you plan to use your own compression algorithm
// other that the standard algorithm 8(deflate)
// the init block is commentted out as it is not used in this example
//func init() {
// see https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
// section 4.4.5 for the available compression methods...which are not implemented by Golang....
// only algorithm 0 and number 8(deflate) available
// var comp zip.Compressor
// zip.RegisterCompressor(999, comp)
//}
func main() {
flag.Parse()
filename := flag.Arg(0)
if filename == "" {
fmt.Println("Usage go-zip sourcefile")
os.Exit(1)
}
fmt.Printf("Zipping file. \n")
err := zipfile(filename)
if err != nil {
fmt.Println(err)
os.Exit(1)
}
fmt.Println("Zipped to ", filename+".zip")
}
func zipfile(filename string) error {
newfile, err := os.Create(filename + ".zip")
if err != nil {
return err
}
defer newfile.Close()
zipit := zip.NewWriter(newfile)
defer zipit.Close()
zipfile, err := os.Open(filename)
if err != nil {
return err
}
defer zipfile.Close()
// get the file information
info, err := zipfile.Stat()
if err != nil {
return err
}
header, err := zip.FileInfoHeader(info)
if err != nil {
return err
}
// default is Store 0(no compression!)
// forking important !!
// change to deflate
// see http://golang.org/pkg/archive/zip/#pkg-constants
header.Method = zip.Deflate
writer, err := zipit.CreateHeader(header)
if err != nil {
return err
}
_, err = io.Copy(writer, zipfile)
return err
}
test out the go-zip.go
by >go run go-zip.go [filename]
Reference:
See also : Golang : Unzip file
By Adam Ng
IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.
Advertisement
Tutorials
+5.6k Golang : When to use make or new?
+8.2k Golang : Read file with ioutil
+6.9k Golang : Check from web if Go application is running or not
+8.2k Golang : Temperatures conversion example
+4.5k Golang : Display advertisement images or strings on random order
+12.4k Golang : Query string with space symbol %20 in between
+5.9k Golang : Levenshtein distance example
+25.5k Golang : dial tcp: too many colons in address
+5.1k Golang : Convert Chinese UTF8 characters to Pin Yin
+28.2k Golang : Login(Authenticate) with Facebook example
+10.4k Golang : Secure file deletion with wipe example
+12.9k Golang : Convert IP version 6 address to integer or decimal number