1. 带进度条大文件下载

1.1.2. 带进度条的大文件下载

import (
    "fmt"
    "io"
    "net/http"
    "os"
    "strings"
    "github.com/dustin/go-humanize"
)
type WriteCounter struct {
    Total uint64
}
func (wc *WriteCounter) Write(p []byte) (int, error) {
    n := len(p)
    wc.PrintProgress()
}
func (wc WriteCounter) PrintProgress() {
    fmt.Printf("\r%s", strings.Repeat(" ", 35))
    fmt.Printf("\rDownloading... %s complete", humanize.Bytes(wc.Total))
}
func main() {
    fmt.Println("Download Started")
    fileUrl := "http://topgoer.com/static/2/9.png"
    err := DownloadFile("9.png", fileUrl)
    if err != nil {
        panic(err)
    }
    fmt.Println("Download Finished")
}
    if err != nil {
        return err
    }
    resp, err := http.Get(url)
    if err != nil {
        out.Close()
        return err
    }
    defer resp.Body.Close()
    counter := &WriteCounter{}
    if _, err = io.Copy(out, io.TeeReader(resp.Body, counter)); err != nil {
        out.Close()
        return err
    }
    fmt.Print("\n")
    out.Close()
    if err = os.Rename(filepath+".tmp", filepath); err != nil {
        return err
    }
}