golang HTTP 包 上传文件

post 上传文件

//在上传文件的实例中,bodyWrite不能在http.DO()之后 ,也就是这里的Client.Do())
func HttpFileFunction(Url, file_name string) (resp *http.Response, err error) {
	bodyBuf := &bytes.Buffer{}
	bodyWrite := multipart.NewWriter(bodyBuf)
	if err != nil {
		fmt.Println("create form file", err)
		return
	}

	file, err := os.Open("photos\\" + file_name)
	defer file.Close()
	if err != nil {
		fmt.Println("加载文件失败", err)
		return
	}
	fileWrite, err := bodyWrite.CreateFormFile("file", file_name)
	
	_,err = io.Copy(fileWrite,file)
	if err != nil {
		fmt.Println("io Copy error",err)
		return
	}

	contentType := bodyWrite.FormDataContentType()
	bodyWrite.Close() //正确位置            ✓
	request, err := http.NewRequest("POST", Url, bodyBuf)
	if err != nil {
		fmt.Println("http newrequest error",err)
		return
	}
	
	request.Header.Set("Content-Type", contentType)

	for _, value := range Cookies {
		fmt.Println("cookie", value)
		request.AddCookie(value)
	}
	fmt.Println(request.ContentLength)

	resp, err = Client.Do(request)
	//bodyWrite.Close() //错误位置         ✘
        //在上传时，会提示真实长度和提交的长度不符合
	if err != nil {
		return
	}
	for _, value := range resp.Cookies() {
		Cookies = append(Cookies, value)
	}
	return
}