netboot/dhcp6/boot_configuration.go

package dhcp6

import (
	"net/http"
	"time"
	"strings"
	"fmt"
	"net/url"
	"bytes"
)

type BootConfiguration interface {
	GetBootUrl(id []byte, clientArchType uint16) ([]byte, error)
}

type StaticBootConfiguration struct {
	HttpBootUrl []byte
	IPxeBootUrl	[]byte
}

func MakeStaticBootConfiguration(httpBootUrl, ipxeBootUrl string) *StaticBootConfiguration {
	return &StaticBootConfiguration{HttpBootUrl: []byte(httpBootUrl), IPxeBootUrl: []byte(ipxeBootUrl)}
}

func (bc *StaticBootConfiguration) GetBootUrl(id []byte, clientArchType uint16) ([]byte, error) {
	if 0x10 ==  clientArchType {
		return bc.HttpBootUrl, nil
	}
	return bc.IPxeBootUrl, nil
}

type ApiBootConfiguration struct {
	client    *http.Client
	urlPrefix string
}

func MakeApiBootConfiguration(url string, timeout time.Duration) *ApiBootConfiguration {
	if !strings.HasSuffix(url, "/") {
		url += "/"
	}
	return &ApiBootConfiguration{
		client:    &http.Client{Timeout: timeout},
		urlPrefix: url + "v1",
	}
}

func (bc *ApiBootConfiguration) GetBootUrl(id []byte, clientArchType uint16) ([]byte, error) {
	reqURL := fmt.Sprintf("%s/boot/%x/%d", bc.urlPrefix, id, clientArchType)
	resp, err := bc.client.Get(reqURL)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		resp.Body.Close()
		return nil, fmt.Errorf("%s: %s", reqURL, http.StatusText(resp.StatusCode))
	}
	defer resp.Body.Close()

	buf := new(bytes.Buffer)
	buf.ReadFrom(resp.Body)
	url, _ := bc.makeURLAbsolute(buf.String())

	return []byte(url), nil
}

func (bc *ApiBootConfiguration) makeURLAbsolute(urlStr string) (string, error) {
	u, err := url.Parse(urlStr)
	if err != nil {
		return "", fmt.Errorf("%q is not an URL", urlStr)
	}
	if !u.IsAbs() {
		base, err := url.Parse(bc.urlPrefix)
		if err != nil {
			return "", err
		}
		u = base.ResolveReference(u)
	}
	return u.String(), nil
}