golang download file with progress

download.go

package main

/**
 * @website http://albulescu.ro
 * @author Cosmin Albulescu <cosmin@albulescu.ro>
 */

import (
	"bytes"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"path"
	"strconv"
	"time"
)

func PrintDownloadPercent(done chan int64, path string, total int64) {

	var stop bool = false

	for {
		select {
		case <-done:
			stop = true
		default:

			file, err := os.Open(path)
			if err != nil {
				log.Fatal(err)
			}

			fi, err := file.Stat()
			if err != nil {
				log.Fatal(err)
			}

			size := fi.Size()

			if size == 0 {
				size = 1
			}

			var percent float64 = float64(size) / float64(total) * 100

			fmt.Printf("%.0f", percent)
			fmt.Println("%")
		}

		if stop {
			break
		}

		time.Sleep(time.Second)
	}
}

func DownloadFile(url string, dest string) {

	file := path.Base(url)

	log.Printf("Downloading file %s from %s\n", file, url)

	var path bytes.Buffer
	path.WriteString(dest)
	path.WriteString("/")
	path.WriteString(file)

	start := time.Now()

	out, err := os.Create(path.String())

	if err != nil {
		fmt.Println(path.String())
		panic(err)
	}

	defer out.Close()

	headResp, err := http.Head(url)

	if err != nil {
		panic(err)
	}

	defer headResp.Body.Close()

	size, err := strconv.Atoi(headResp.Header.Get("Content-Length"))

	if err != nil {
		panic(err)
	}

	done := make(chan int64)

	go PrintDownloadPercent(done, path.String(), int64(size))

	resp, err := http.Get(url)

	if err != nil {
		panic(err)
	}

	defer resp.Body.Close()

	n, err := io.Copy(out, resp.Body)

	if err != nil {
		panic(err)
	}

	done <- n

	elapsed := time.Since(start)
	log.Printf("Download completed in %s", elapsed)
}


func main() {
    DownloadFile("https://wordpress.org/wordpress-4.4.2.zip","./")
}

who will give url instead of path ?? Waste Code

who will give url instead of path ?? Waste Code

Please be polite.

Cool and useful for me! Thanks

This was helpful.. Thanks!

Good stuff!
I had an issue after downloading a file I couldn't move it to another folder because of the following error: The process cannot access the file because it is being used by another process. and realised you probably need to file.Close(). I also moved os.Open(path) outside of the for loop.

Now it looks something like this:

func PrintDownloadPercent(done chan int64, path string, total int64) {
	var stop bool = false
        file, err := os.Open(path)
	if err != nil {
		log.Fatal(err)
	}
        defer file.Close()
	for {
		select {
		case <-done:
			stop = true
		default:
			fi, err := file.Stat()
			if err != nil {
				log.Fatal(err)
			}

			size := fi.Size()
			if size == 0 {
				size = 1
			}

			var percent float64 = float64(size) / float64(total) * 100
			fmt.Printf("%.0f", percent)
			fmt.Println("%")
		}

		if stop {
			break
		}
		time.Sleep(time.Second)
	}
}

Nice one =). Thanks for sharing