sources.go

   1 package torrent
   2
   3 import (
   4         "context"
   5         "fmt"
   6         "net/http"
   7
   8         "github.com/anacrolix/log"
   9         "github.com/anacrolix/torrent/bencode"
  10         "github.com/anacrolix/torrent/metainfo"
  11 )
  12
  13 func (t *Torrent) useSources(sources []string) {
  14         select {
  15         case <-t.Closed():
  16                 return
  17         case <-t.GotInfo():
  18                 return
  19         default:
  20         }
  21         for _, s := range sources {
  22                 _, loaded := t.activeSources.LoadOrStore(s, struct{}{})
  23                 if loaded {
  24                         continue
  25                 }
  26                 s := s
  27                 go func() {
  28                         err := t.useActiveTorrentSource(s)
  29                         _, loaded := t.activeSources.LoadAndDelete(s)
  30                         if !loaded {
  31                                 panic(s)
  32                         }
  33                         level := log.Debug
  34                         if err != nil {
  35                                 level = log.Warning
  36                         }
  37                         t.logger.Levelf(level, "used torrent source %q [err=%v]", s, err)
  38                 }()
  39         }
  40 }
  41
  42 func (t *Torrent) useActiveTorrentSource(source string) error {
  43         ctx, cancel := context.WithCancel(context.Background())
  44         defer cancel()
  45         go func() {
  46                 select {
  47                 case <-t.GotInfo():
  48                 case <-t.Closed():
  49                 case <-ctx.Done():
  50                 }
  51                 cancel()
  52         }()
  53         mi, err := getTorrentSource(ctx, source, t.cl.httpClient)
  54         if err != nil {
  55                 return err
  56         }
  57         return t.MergeSpec(TorrentSpecFromMetaInfo(&mi))
  58 }
  59
  60 func getTorrentSource(ctx context.Context, source string, hc *http.Client) (mi metainfo.MetaInfo, err error) {
  61         var req *http.Request
  62         if req, err = http.NewRequestWithContext(ctx, http.MethodGet, source, nil); err != nil {
  63                 return
  64         }
  65         var resp *http.Response
  66         if resp, err = hc.Do(req); err != nil {
  67                 return
  68         }
  69         defer resp.Body.Close()
  70         if resp.StatusCode != http.StatusOK {
  71                 err = fmt.Errorf("unexpected response status code: %v", resp.StatusCode)
  72                 return
  73         }
  74         err = bencode.NewDecoder(resp.Body).Decode(&mi)
  75         return
  76 }