tracker/http.go

   1 package tracker
   2
   3 import (
   4         "bytes"
   5         "errors"
   6         "fmt"
   7         "io"
   8         "net/http"
   9         "net/url"
  10         "strconv"
  11
  12         "github.com/anacrolix/dht/krpc"
  13         "github.com/anacrolix/missinggo/httptoo"
  14
  15         "github.com/anacrolix/torrent/bencode"
  16 )
  17
  18 type httpResponse struct {
  19         FailureReason string `bencode:"failure reason"`
  20         Interval      int32  `bencode:"interval"`
  21         TrackerId     string `bencode:"tracker id"`
  22         Complete      int32  `bencode:"complete"`
  23         Incomplete    int32  `bencode:"incomplete"`
  24         Peers         Peers  `bencode:"peers"`
  25         // BEP 7
  26         Peers6 krpc.CompactIPv6NodeAddrs `bencode:"peers6"`
  27 }
  28
  29 type Peers []Peer
  30
  31 func (me *Peers) UnmarshalBencode(b []byte) (err error) {
  32         var _v interface{}
  33         err = bencode.Unmarshal(b, &_v)
  34         if err != nil {
  35                 return
  36         }
  37         switch v := _v.(type) {
  38         case string:
  39                 vars.Add("http responses with string peers", 1)
  40                 var cnas krpc.CompactIPv4NodeAddrs
  41                 err = cnas.UnmarshalBinary([]byte(v))
  42                 if err != nil {
  43                         return
  44                 }
  45                 for _, cp := range cnas {
  46                         *me = append(*me, Peer{
  47                                 IP:   cp.IP[:],
  48                                 Port: int(cp.Port),
  49                         })
  50                 }
  51                 return
  52         case []interface{}:
  53                 vars.Add("http responses with list peers", 1)
  54                 for _, i := range v {
  55                         var p Peer
  56                         p.fromDictInterface(i.(map[string]interface{}))
  57                         *me = append(*me, p)
  58                 }
  59                 return
  60         default:
  61                 vars.Add("http responses with unhandled peers type", 1)
  62                 err = fmt.Errorf("unsupported type: %T", _v)
  63                 return
  64         }
  65 }
  66
  67 func setAnnounceParams(_url *url.URL, ar *AnnounceRequest, opts Announce) {
  68         q := _url.Query()
  69
  70         q.Set("info_hash", string(ar.InfoHash[:]))
  71         q.Set("peer_id", string(ar.PeerId[:]))
  72         q.Set("port", fmt.Sprintf("%d", ar.Port))
  73         q.Set("uploaded", strconv.FormatInt(ar.Uploaded, 10))
  74         q.Set("downloaded", strconv.FormatInt(ar.Downloaded, 10))
  75         q.Set("left", strconv.FormatUint(ar.Left, 10))
  76         if ar.Event != None {
  77                 q.Set("event", ar.Event.String())
  78         }
  79         // http://stackoverflow.com/questions/17418004/why-does-tracker-server-not-understand-my-request-bittorrent-protocol
  80         q.Set("compact", "1")
  81         // According to https://wiki.vuze.com/w/Message_Stream_Encryption. TODO:
  82         // Take EncryptionPolicy or something like it as a parameter.
  83         q.Set("supportcrypto", "1")
  84         if opts.ClientIp4.IP != nil {
  85                 q.Set("ipv4", opts.ClientIp4.String())
  86         }
  87         if opts.ClientIp6.IP != nil {
  88                 q.Set("ipv6", opts.ClientIp6.String())
  89         }
  90         _url.RawQuery = q.Encode()
  91 }
  92
  93 func announceHTTP(opt Announce, _url *url.URL) (ret AnnounceResponse, err error) {
  94         _url = httptoo.CopyURL(_url)
  95         setAnnounceParams(_url, &opt.Request, opt)
  96         req, err := http.NewRequest("GET", _url.String(), nil)
  97         req.Header.Set("User-Agent", opt.UserAgent)
  98         req.Host = opt.HostHeader
  99         resp, err := opt.HttpClient.Do(req)
 100         if err != nil {
 101                 return
 102         }
 103         defer resp.Body.Close()
 104         var buf bytes.Buffer
 105         io.Copy(&buf, resp.Body)
 106         if resp.StatusCode != 200 {
 107                 err = fmt.Errorf("response from tracker: %s: %s", resp.Status, buf.String())
 108                 return
 109         }
 110         var trackerResponse httpResponse
 111         err = bencode.Unmarshal(buf.Bytes(), &trackerResponse)
 112         if err != nil {
 113                 err = fmt.Errorf("error decoding %q: %s", buf.Bytes(), err)
 114                 return
 115         }
 116         if trackerResponse.FailureReason != "" {
 117                 err = errors.New(trackerResponse.FailureReason)
 118                 return
 119         }
 120         vars.Add("successful http announces", 1)
 121         ret.Interval = trackerResponse.Interval
 122         ret.Leechers = trackerResponse.Incomplete
 123         ret.Seeders = trackerResponse.Complete
 124         if len(trackerResponse.Peers) != 0 {
 125                 vars.Add("http responses with nonempty peers key", 1)
 126         }
 127         ret.Peers = trackerResponse.Peers
 128         if len(trackerResponse.Peers6) != 0 {
 129                 vars.Add("http responses with nonempty peers6 key", 1)
 130         }
 131         for _, na := range trackerResponse.Peers6 {
 132                 ret.Peers = append(ret.Peers, Peer{
 133                         IP:   na.IP,
 134                         Port: na.Port,
 135                 })
 136         }
 137         return
 138 }