57 lines
1014 B
Go
57 lines
1014 B
Go
package torrent
|
|
|
|
import (
|
|
"encoding/base32"
|
|
"encoding/hex"
|
|
"fmt"
|
|
"net/url"
|
|
"strings"
|
|
)
|
|
|
|
type Magnet struct {
|
|
InfoHash [20]byte
|
|
Trackers []string
|
|
DisplayName string
|
|
}
|
|
|
|
const xtPrefix = "urn:btih:"
|
|
|
|
func ParseMagnetURI(uri string) (m Magnet, err error) {
|
|
u, err := url.Parse(uri)
|
|
if err != nil {
|
|
err = fmt.Errorf("error parsing uri: %s", err)
|
|
return
|
|
}
|
|
xt := u.Query().Get("xt")
|
|
if !strings.HasPrefix(xt, xtPrefix) {
|
|
err = fmt.Errorf("bad xt parameter")
|
|
return
|
|
}
|
|
xt = xt[len(xtPrefix):]
|
|
decode := func() func(dst, src []byte) (int, error) {
|
|
switch len(xt) {
|
|
case 40:
|
|
return hex.Decode
|
|
case 32:
|
|
return base32.StdEncoding.Decode
|
|
default:
|
|
return nil
|
|
}
|
|
}()
|
|
if decode == nil {
|
|
err = fmt.Errorf("unhandled xt parameter encoding")
|
|
return
|
|
}
|
|
n, err := decode(m.InfoHash[:], []byte(xt))
|
|
if err != nil {
|
|
err = fmt.Errorf("error decoding xt: %s", err)
|
|
return
|
|
}
|
|
if n != 20 {
|
|
panic(n)
|
|
}
|
|
m.DisplayName = u.Query().Get("dn")
|
|
m.Trackers = u.Query()["tr"]
|
|
return
|
|
}
|