Golang : Progress bar with ∎ character
This tutorial is add on to the previous tutorial on how upload/receive progress indicator. Just a slight modification, where the progress is indicated by ∎ character and % completed.
NOTE : To add % sign after %v, use two % symbols.
Here you go :
package main
import (
"fmt"
"io"
"net/http"
"os"
"strings"
"time"
)
const (
barChar = "∎"
)
func uploadPage(w http.ResponseWriter, r *http.Request) {
w.Write([]byte(fmt.Sprintf("<html><title>Go upload</title><body><form action='http://localhost:8080/receive' method='post' enctype='multipart/form-data'><label for='file'>Filename:</label><input type='file' name='file' id='file'><input type='submit' value='Upload' ></form></body></html>")))
}
func uploadProgress(w http.ResponseWriter, r *http.Request) {
mr, err := r.MultipartReader()
if err != nil {
fmt.Fprintln(w, err)
return
}
length := r.ContentLength
//ticker := time.Tick(time.Millisecond) // <-- use this in production
ticker := time.Tick(time.Second) // this is for demo purpose with longer delay
for {
var read int64
var p float32
part, err := mr.NextPart()
if err == io.EOF {
fmt.Printf("\nDone!")
break
}
dst, err := os.OpenFile("upload.jpg", os.O_WRONLY|os.O_CREATE, 0666)
if err != nil {
return
}
var barLen int
for {
buffer := make([]byte, 100000)
cBytes, err := part.Read(buffer)
if err == io.EOF {
fmt.Printf("\nLast buffer read!")
break
}
read = read + int64(cBytes)
//fmt.Printf("\r read: %v length : %v \n", read, length)
if read > 0 {
p = float32(read*100) / float32(length)
barLen = int(p)
//fmt.Printf("progress: %v \n", strings.Repeat(barChar,barLen))
<-ticker
fmt.Printf("\rStatus: %v [%v%%]", strings.Repeat(barChar, barLen), p)
//fmt.Printf("\rUploading progress %v", p) // for console
dst.Write(buffer[0:cBytes])
} else {
break
}
}
}
}
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/", uploadPage)
mux.HandleFunc("/receive", uploadProgress)
http.ListenAndServe(":8080", mux)
}
Sample output :
go run uploadprogress.go
Status: ∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎ [99.915634%]
Last buffer read!
See also : Golang : Upload/Receive file progress indicator
By Adam Ng
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