FinalCommander/content/server.go

package content

import (
	"crypto/tls"
	"encoding/base64"
	"fmt"
	"git.gammaspectra.live/S.O.N.G/FinalCommander/utilities"
	"git.gammaspectra.live/S.O.N.G/MakyuuIchaival"
	"git.gammaspectra.live/S.O.N.G/MakyuuIchaival/contentmessage"
	"github.com/cloudflare/circl/sign/ed25519"
	"github.com/multiformats/go-multihash"
	"net/http"
	"strconv"
	"strings"
	"sync"
	"time"
)

type ServerProtocol int

const (
	ProtocolOrbitalBeatV1 ServerProtocol = iota
)

type Server struct {
	Index           int
	Address         string
	Protocol        ServerProtocol
	key             []byte
	Weight          uint
	LastCheckResult bool
	lastCheckMutex  sync.RWMutex
}

func NewContentServerFromArgument(arg string, index int, defaultKey []byte) (*Server, error) {
	//Format Address:PORT/WEIGHT[/publicKey],

	protos := strings.Split(arg, "=")

	serverProtocol := ProtocolOrbitalBeatV1

	serverKey := defaultKey

	if len(protos) > 1 {
		switch protos[0] {
		case "orbt":
			serverProtocol = ProtocolOrbitalBeatV1

		default:
			return nil, fmt.Errorf("invalid server Protocol %s", arg)
		}
	}

	p := strings.Split(protos[len(protos)-1], "/")
	if len(p) < 2 {
		return nil, fmt.Errorf("invalid weighted server %s", arg)
	}

	weight, err := strconv.ParseUint(p[1], 10, 32)
	if err != nil {
		return nil, err
	}

	cs := &Server{
		Index:           index,
		Address:         p[0],
		Protocol:        serverProtocol,
		key:             serverKey,
		Weight:          uint(weight),
		LastCheckResult: false,
	}

	return cs, nil
}

func (s *Server) GetContentURL(content *Entry, skip []int) string {
	switch s.Protocol {
	case ProtocolOrbitalBeatV1:
		message := contentmessage.NewContentMessageV1(content.Multihash(), ed25519.PrivateKey(s.key))
		skip = append(skip, s.Index)
		return s.getBaseURL(MakyuuIchaival.Bech32Encoding.EncodeToString(message.Encode()), MakyuuIchaival.Bech32Encoding.EncodeToString(utilities.EncodeIntegerList(skip)))
	default:
		return ""
	}
}

func (s *Server) GetHashURL(mh multihash.Multihash, skip []int) string {
	switch s.Protocol {
	case ProtocolOrbitalBeatV1:
		message := contentmessage.NewContentMessageV1(mh, ed25519.PrivateKey(s.key))
		skip = append(skip, s.Index)
		return s.getBaseURL(MakyuuIchaival.Bech32Encoding.EncodeToString(message.Encode()), MakyuuIchaival.Bech32Encoding.EncodeToString(utilities.EncodeIntegerList(skip)))
	default:
		return ""
	}
}

func (s *Server) getBaseURL(args ...string) string {
	return fmt.Sprintf("https://%s/%s", s.Address, strings.Join(args, "/"))
}

func (s *Server) GetCheckResult() bool {
	s.lastCheckMutex.RLock()
	defer s.lastCheckMutex.RUnlock()
	return s.LastCheckResult
}

func (s *Server) setCheckResult(result bool) {
	s.lastCheckMutex.Lock()
	defer s.lastCheckMutex.Unlock()
	s.LastCheckResult = result
}

func (s *Server) Check() {
	customTransport := http.DefaultTransport.(*http.Transport).Clone()
	customTransport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
	client := &http.Client{
		Transport: customTransport,
		Timeout:   5 * time.Second,
	}
	response, err := client.Head(s.getBaseURL())

	if err != nil {
		s.setCheckResult(false)
		return
	}

	defer response.Body.Close()

	if response.StatusCode != http.StatusBadRequest {
		s.setCheckResult(false)
		return
	}
	s.setCheckResult(true)
}

func (s *Server) CheckEntryKey(key *HashIdentifier) (*HashIdentifier, error) {
	customTransport := http.DefaultTransport.(*http.Transport).Clone()
	customTransport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
	client := &http.Client{
		Transport: customTransport,
		Timeout:   5 * time.Second,
	}
	response, err := client.Head(s.GetHashURL(key.Hash(), []int{}))

	if err != nil {
		return nil, err
	}

	defer response.Body.Close()

	if response.StatusCode == http.StatusNotFound {
		return nil, nil
	}

	if response.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("unexpected status code %d", response.StatusCode)
	}

	v := strings.Split(response.Header.Get("Digest"), "=")
	if len(v) >= 2 && v[0] == "sha-256" {
		sha, err := base64.StdEncoding.DecodeString(strings.Join(v[1:], "="))
		if err != nil {
			return nil, nil
		}
		mh, err := multihash.Encode(sha, multihash.SHA2_256)
		if err != nil {
			return nil, nil
		}
		return NewHashIdentifierFromMultihash(mh), nil
	}

	return nil, nil
}