golang multipart/form-data POST上传文件

package main

import (
"bytes"
"errors"
"fmt"
"io/ioutil"
"mime/multipart"
"net/http"
)

func main() {
createMemoToAmazon()
}

func createMemoToAmazon() error {
buf := new(bytes.Buffer)
w := multipart.NewWriter(buf)

err := w.WriteField("comment", "我的世界！！！")
if err != nil {
fmt.Println(err)
return err
}

resp, err := http.Get("http://www.xxx.com/1d595495-0580-49ec-b96c-cc3346096718")
if err != nil {
fmt.Println(err)
return err
}
defer resp.Body.Close()

if resp.StatusCode != 200 {
return errors.New("resp status:" + fmt.Sprint(resp.StatusCode))
}

bin, err := ioutil.ReadAll(resp.Body)
if err != nil {
fmt.Println(err)
return err
}

fw, err := w.CreateFormFile("file", "1d595495-0580-49ec-b96c-cc3346096718")
if err != nil {
fmt.Println(err)
return err
}

_, err = fw.Write(bin)
if err != nil {
fmt.Println(err)
return err
}
w.Close()

req, err := http.NewRequest("POST", "http://localhost:8080/info", buf)
if err != nil {
fmt.Println("req err: ", err)
return err
}
req.Header.Set("Content-Type", w.FormDataContentType())

resp, err = http.DefaultClient.Do(req)
if err != nil {
fmt.Println("resp err: ", err)
return err
}
defer resp.Body.Close()

if resp.StatusCode != 200 {
return errors.New("resp status:" + fmt.Sprint(resp.StatusCode))
}

return nil
}

func CreateFormFile(fieldname, filename, contentType string, w *multipart.Writer) (io.Writer, error) {
h := make(textproto.MIMEHeader)
h.Set("Content-Disposition",
fmt.Sprintf(`form-data; name="%s"; filename="%s"`,
escapeQuotes(fieldname), escapeQuotes(filename)))
h.Set("Content-Type", contentType)
return w.CreatePart(h)
}