gzip compression/decompression example

main.go

package main

import (
	"fmt"
	"compress/gzip"
	"io"
	"io/ioutil"
	"bytes"
	"log"
)

// Write gzipped data to a Writer
func gzipWrite(w io.Writer, data []byte) error {
	// Write gzipped data to the client
	gw, err := gzip.NewWriterLevel(w, gzip.BestSpeed)
	defer gw.Close()
	gw.Write(data)
	return err
}

// Write gunzipped data to a Writer
func gunzipWrite(w io.Writer, data []byte) error {
	// Write gzipped data to the client
	gr, err := gzip.NewReader(bytes.NewBuffer(data))
	defer gr.Close()
	data, err = ioutil.ReadAll(gr)
	if err != nil {
		return err
	}
	w.Write(data)
	return nil
}

func main() {
	s := "some data"
	fmt.Println("original:\t", s)
	
	var buf bytes.Buffer
	err := gzipWrite(&buf, []byte(s))
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("compressed:\t", buf.String())
	
	var buf2 bytes.Buffer
	err = gunzipWrite(&buf2, buf.Bytes())
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("decompressed:\t", buf2.String())
}

If you to compress an xml file which is in the same directory where your program is saved how can we save the gzip file that you created.

@Shailesh1994 Here's one way:

data, err := ioutil.ReadFile("test.xml")
if err != nil {
    log.Fatal(err)
}

file, err := os.Create("test.xml.gz")
if err != nil {
    log.Fatal(err)
}

err = gzipWrite(file, data)
if err != nil {
    log.Fatal(err)
}

Thank you so much Sir

…

On Thu, Jan 30, 2020, 13:44 Alexander F. Rødseth ***@***.***> wrote: @Shailesh1994 <https://github.com/Shailesh1994> Here's one way: data, err := ioutil.ReadFile("test.xml")if err != nil { log.Fatal(err) } file, err := os.Create("test.xml.gz")if err != nil { log.Fatal(err) } err = gzipWrite(file, data)if err != nil { log.Fatal(err) } — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <https://gist.github.com/f4915d7e208771f3adc4?email_source=notifications&email_token=ALFWZPD465EIC5J6JDGTJVLRAKD7HA5CNFSM4KNQDQDKYY3PNVWWK3TUL52HS4DFVNDWS43UINXW23LFNZ2KUY3PNVWWK3TUL5UWJTQAGA5UG#gistcomment-3160899>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ALFWZPGRP5KD6VI4R25QJKLRAKD7HANCNFSM4KNQDQDA> .

Do you have a Read Me file of following code and I want to integrate this code for the sitemap .Can you help me out if possible

I don't understand the question. Please try Stack Overflow.

Thanks for the examples!!

Maybe it might be better to use io.Copy when you write?

func gunzipWrite(w io.Writer, data []byte) error {
	// Write gzipped data to the client
	gr, err := gzip.NewReader(bytes.NewBuffer(data))
	defer gr.Close()

	_, err := io.Copy(w, gr)
        return err
}

Yes, io.Copy is probably better.

can we read gz file in chunks?

Yes, just use io.CopyN instead of io.Copy.