Post media to twitter using go-twitter

main.go

func PublishTW(file string) {
	config := oauth1.NewConfig(token.TWcon, token.TWconSEC)
	token := oauth1.NewToken(token.TW, token.TWsec)
	httpClient := config.Client(oauth1.NoContext, token)
	b := &bytes.Buffer{}
	form := multipart.NewWriter(b)
	fw, err := form.CreateFormFile("media", file)
	if err != nil {
		panic(err)
	}
	opened, err := os.Open(file)
	if err != nil {
		panic(err)
	}
	_, err = io.Copy(fw, opened)
	if err != nil {
		panic(err)
	}

	// post picture
	form.Close()
	resp, err :=
		httpClient.Post("https://upload.twitter.com/1.1/media/upload.json?media_category=tweet_image",
			form.FormDataContentType(), bytes.NewReader(b.Bytes()))
	if err != nil {
		fmt.Printf("Error: %s\n", err)
	}
	defer resp.Body.Close()
	m := &MediaUpload{}
	_ = json.NewDecoder(resp.Body).Decode(m)
	mid := strconv.Itoa(m.MediaId)
	resp, err = httpClient.PostForm("https://api.twitter.com/1.1/statuses/update.json",
		url.Values{"status": {"Post the status!"}, "media_ids": {mid}})
	if err != nil {
		fmt.Printf("Error: %s\n", err)
	}
}