Track and show uploaded file (percentage) - Go lang
I am making a process that downloads a file via a passed url parameter. the download is doing correctly, but I cannot print a summary of the download percentage. (every second)
ive built one simulated view of this resume but it doesn't get loaded, it just show how I want it.
I tried to bring io.copy inside my source so I can change its ant print while copying, but it doesn't work.
Can anyone help me? thank
package main
import (
"fmt"
"io"
"net/http"
"os"
"strings"
// "time"
)
func downloadFromUrl(url string) {
tokens := strings.Split(url, "/")
fileName := tokens[len(tokens)-1]
fmt.Println("Downloading", url, "to", fileName)
//create file
output, err := os.Create(fileName)
if err != nil {
fmt.Println("Error while creating", fileName, "-", err)
return
}
fmt.Println("Creating", fileName)
defer output.Close()
//get url
response, err := http.Get(url)
if err != nil {
fmt.Println("Error while downloading", url, "-", err)
return
}
defer response.Body.Close()
//copy and bytes
n, err := io.Copy(output, response.Body)
if err != nil {
fmt.Println("Error while downloading", url, "-", err)
return
}
//track progress
for i := 1; float64(i) < float64(n); i++ {
fmt.Println("",float64(i),float64(n))
percent := float64(i) / (float64(n) / float64(100))
percentTot := fmt.Sprintf(" %#.02f%% ", percent)
fmt.Println(percentTot,"downloaded\n")
//time.Sleep(3000 * time.Millisecond)
}
}
func main() {
//read args
args := os.Args
//loop args
for i := 1; i < len(args); i++ {
url := args[i]
//call download
downloadFromUrl(url)
}
}
**Output:**
go run main.go http://download.geonames.org/export/dump/AD.zip
Downloading http://download.geonames.org/export/dump/AD.zip to AD.zip
Creating AD.zip
1 64639
0.00% downloaded
2 64639
0.00% downloaded
3 64639
0.00% downloaded
4 64639
0.01% downloaded
5 64639
0.01% downloaded
source to share
I did this in my senvgo project with a wrapperio.Reader
// PassThru wraps an existing io.Reader.
//
// It simply forwards the Read() call, while displaying
// the results from individual calls to it.
type PassThru struct {
io.Reader
total int64 // Total # of bytes transferred
length int64 // Expected length
progress float64
}
You define a method Read()
on this shell (to make it io.Reader
)
// Read 'overrides' the underlying io.Reader Read method.
// This is the one that will be called by io.Copy(). We simply
// use it to keep track of byte counts and then forward the call.
func (pt *PassThru) Read(p []byte) (int, error) {
n, err := pt.Reader.Read(p)
if n > 0 {
pt.total += int64(n)
percentage := float64(pt.total) / float64(pt.length) * float64(100)
i := int(percentage / float64(10))
is := fmt.Sprintf("%v", i)
if percentage-pt.progress > 2 {
fmt.Fprintf(os.Stderr, is)
pt.progress = percentage
}
}
return n, err
}
And you use this one io.Reader
to read Response
(the result of your HTTP request):
client := &http.Client{
CheckRedirect: redirectPolicyFunc,
}
response, err := client.Get("http://example.com/something/large.zip")
defer response.Body.Close()
readerpt := &PassThru{Reader: response.Body, length: response.ContentLength}
body, err := ioutil.ReadAll(readerpt)
The call ReadAll()
causes the actual load, and PassThru.Read()
will print the% loaded with the expected length ( response.ContentLength
)
Inspirations:
- this play.golang.orgfor the Copy () function
- " How do I print bytes while downloading a file? "
source to share