torrent/tracker/tracker.go

97 lines
2.0 KiB
Go

package tracker
import (
"errors"
"net"
"net/url"
)
// Marshalled as binary by the UDP client, so be careful making changes.
type AnnounceRequest struct {
InfoHash [20]byte
PeerId [20]byte
Downloaded int64
Left uint64
Uploaded int64
Event AnnounceEvent
IPAddress int32
Key int32
NumWant int32 // How many peer addresses are desired. -1 for default.
Port uint16
} // 82 bytes
type AnnounceResponse struct {
Interval int32 // Minimum seconds the local peer should wait before next announce.
Leechers int32
Seeders int32
Peers []Peer
}
type AnnounceEvent int32
func (e AnnounceEvent) String() string {
// See BEP 3, "event".
return []string{"empty", "completed", "started", "stopped"}[e]
}
type Peer struct {
IP net.IP
Port int
}
const (
None AnnounceEvent = iota
Completed // The local peer just completed the torrent.
Started // The local peer has just resumed this torrent.
Stopped // The local peer is leaving the swarm.
)
type client interface {
// Returns ErrNotConnected if Connect needs to be called.
Announce(*AnnounceRequest) (AnnounceResponse, error)
Connect() error
String() string
URL() string
Close() error
}
var (
ErrNotConnected = errors.New("not connected")
ErrBadScheme = errors.New("unknown scheme")
schemes = make(map[string]func(*url.URL) client)
)
func registerClientScheme(scheme string, newFunc func(*url.URL) client) {
schemes[scheme] = newFunc
}
// Returns ErrBadScheme if the tracker scheme isn't recognised.
func new(rawurl string) (cl client, err error) {
url_s, err := url.Parse(rawurl)
if err != nil {
return
}
newFunc, ok := schemes[url_s.Scheme]
if !ok {
err = ErrBadScheme
return
}
cl = newFunc(url_s)
return
}
func Announce(urlStr string, req *AnnounceRequest) (res AnnounceResponse, err error) {
cl, err := new(urlStr)
if err != nil {
return
}
defer cl.Close()
err = cl.Connect()
if err != nil {
return
}
return cl.Announce(req)
}