golang download file

httpDownload.go

// Download File 
func DownloadFile(url string, headers map[string]string, jsonData string, downloadFilePath string) (downloadedFile string, err error)  {
	
	var jsonStr = []byte(jsonData)
	log.Printf("DownloadFile(): %v\n%+v...", url, jsonStr)

	req, err := http.NewRequest("GET", url, bytes.NewBuffer(jsonStr))

	for k,v := range(headers) {
		log.Printf("setting header %v : %v ", k,v)
		req.Header.Set(k, v)
	}
	
	// does support https?: yes
	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		return
	}
	defer resp.Body.Close()

	bodybytes, _ := ioutil.ReadAll(resp.Body)
	body := string(bodybytes)
	log.Printf("response:\n %+v ", body)

	
	err = CheckResponse(resp, headers["sessionToken"], url, body, []string{}, err)
	if err != nil {
		return
	}

	// get filename
	var filename string
	if cd := resp.Header.Get("Content-Disposition"); cd != "" {
		if _, params, err := mime.ParseMediaType(cd); err == nil {
			filename = params["filename"]
		} else {
			return "", err
		}
	}	

	downloadedFile = filepath.Join(downloadFilePath,filename)

	out, err := os.Create(downloadedFile)
	if err != nil {
		return
	}

	defer out.Close()

	bodyBuffer := bytes.NewBuffer(bodybytes)
	io.Copy(out, bodyBuffer)

	bodybytes, _ = ioutil.ReadAll(resp.Body)
	body = string(bodybytes)
	
	log.Printf("response:\n %+v ", body)

	fi, err := os.Stat(downloadedFile);
	size := fi.Size()

	if err != nil || size == 0 {
		return "", fmt.Errorf("Error downloading file. 0k or does not exist on disk: %+v \n  ", downloadedFile)
	}
	
	

	return
}



// Check http response
func CheckResponse(resp *http.Response, sessionToken string, url string, body string, acceptedCodes []string, err error ) (error) {
	if err != nil {
		return err
	}

	// no errors; return
	if resp.StatusCode == 200 {
		return err
	}

	// session token expired
	if resp.StatusCode == 401 {
		return fmt.Errorf("session token (%v) is invalid or has expired", sessionToken)
	}

	log.Printf("accepted codes: %v", acceptedCodes)

	// check if it's an accepted code for this call
	if strings.Contains(strings.Join(acceptedCodes, ","), string(resp.StatusCode)) {
		return err
	} else {
		return fmt.Errorf("Error: %v\n return status code is %v. response.body: %v", url, resp.StatusCode, body)
	}


	return err
}