sources.go

   1 package torrent
   2
   3 import (
   4         "context"
   5         "net/http"
   6
   7         "github.com/anacrolix/log"
   8         "github.com/anacrolix/torrent/bencode"
   9         "github.com/anacrolix/torrent/metainfo"
  10 )
  11
  12 func (t *Torrent) useSources(sources []string) {
  13         select {
  14         case <-t.Closed():
  15                 return
  16         case <-t.GotInfo():
  17                 return
  18         default:
  19         }
  20         for _, s := range sources {
  21                 _, loaded := t.activeSources.LoadOrStore(s, struct{}{})
  22                 if loaded {
  23                         continue
  24                 }
  25                 s := s
  26                 go func() {
  27                         err := t.useActiveTorrentSource(s)
  28                         _, loaded := t.activeSources.LoadAndDelete(s)
  29                         if !loaded {
  30                                 panic(s)
  31                         }
  32                         level := log.Debug
  33                         if err != nil {
  34                                 level = log.Warning
  35                         }
  36                         t.logger.Levelf(level, "used torrent source %q [err=%q]", s, err)
  37                 }()
  38         }
  39 }
  40
  41 func (t *Torrent) useActiveTorrentSource(source string) error {
  42         ctx, cancel := context.WithCancel(context.Background())
  43         defer cancel()
  44         go func() {
  45                 select {
  46                 case <-t.GotInfo():
  47                 case <-t.Closed():
  48                 case <-ctx.Done():
  49                 }
  50                 cancel()
  51         }()
  52         mi, err := getTorrentSource(ctx, source, t.cl.httpClient)
  53         if err != nil {
  54                 return err
  55         }
  56         return t.MergeSpec(TorrentSpecFromMetaInfo(&mi))
  57 }
  58
  59 func getTorrentSource(ctx context.Context, source string, hc *http.Client) (mi metainfo.MetaInfo, err error) {
  60         var req *http.Request
  61         if req, err = http.NewRequestWithContext(ctx, http.MethodGet, source, nil); err != nil {
  62                 return
  63         }
  64         var resp *http.Response
  65         if resp, err = hc.Do(req); err != nil {
  66                 return
  67         }
  68         defer resp.Body.Close()
  69         err = bencode.NewDecoder(resp.Body).Decode(&mi)
  70         return
  71 }