11 "github.com/RoaringBitmap/roaring"
12 "github.com/anacrolix/torrent/common"
13 "github.com/anacrolix/torrent/metainfo"
14 "github.com/anacrolix/torrent/segments"
17 type RequestSpec = segments.Extent
19 type requestPartResult struct {
24 type requestPart struct {
27 result chan requestPartResult
32 Result chan RequestResult
35 func (r Request) Cancel() {
40 HttpClient *http.Client
42 fileIndex segments.Index
44 // The pieces we can request with the Url. We're more likely to ban/block at the file-level
45 // given that's how requests are mapped to webseeds, but the torrent.Client works at the piece
46 // level. We can map our file-level adjustments to the pieces here.
50 func (me *Client) SetInfo(info *metainfo.Info) {
51 if !strings.HasSuffix(me.Url, "/") && info.IsDir() {
52 // In my experience, this is a non-conforming webseed. For example the
53 // http://ia600500.us.archive.org/1/items URLs in archive.org torrents.
56 me.fileIndex = segments.NewIndex(common.LengthIterFromUpvertedFiles(info.UpvertedFiles()))
58 me.Pieces.AddRange(0, uint64(info.NumPieces()))
61 type RequestResult struct {
66 func (ws *Client) NewRequest(r RequestSpec) Request {
67 ctx, cancel := context.WithCancel(context.Background())
68 var requestParts []requestPart
69 if !ws.fileIndex.Locate(r, func(i int, e segments.Extent) bool {
70 req, err := NewRequest(ws.Url, i, ws.info, e.Start, e.Length)
74 req = req.WithContext(ctx)
77 result: make(chan requestPartResult, 1),
81 resp, err := ws.HttpClient.Do(req)
82 part.result <- requestPartResult{
87 requestParts = append(requestParts, part)
90 panic("request out of file bounds")
94 Result: make(chan RequestResult, 1),
97 b, err := readRequestPartResponses(ctx, requestParts)
98 req.Result <- RequestResult{
106 type ErrBadResponse struct {
108 Response *http.Response
111 func (me ErrBadResponse) Error() string {
115 func recvPartResult(ctx context.Context, buf io.Writer, part requestPart) error {
116 result := <-part.result
117 if result.err != nil {
120 defer result.resp.Body.Close()
121 if ctx.Err() != nil {
124 switch result.resp.StatusCode {
125 case http.StatusPartialContent:
127 if part.e.Start != 0 {
128 return ErrBadResponse{"got status ok but request was at offset", result.resp}
131 return ErrBadResponse{
132 fmt.Sprintf("unhandled response status code (%v)", result.resp.StatusCode),
136 copied, err := io.Copy(buf, result.resp.Body)
140 if copied != part.e.Length {
141 return fmt.Errorf("got %v bytes, expected %v", copied, part.e.Length)
146 func readRequestPartResponses(ctx context.Context, parts []requestPart) ([]byte, error) {
147 ctx, cancel := context.WithCancel(ctx)
150 firstErr := make(chan error, 1)
152 for _, part := range parts {
153 err := recvPartResult(ctx, &buf, part)
155 // Ensure no further unnecessary response reads occur.
158 case firstErr <- fmt.Errorf("reading %q at %q: %w", part.req.URL, part.req.Header.Get("Range"), err):
164 case firstErr <- nil:
168 // This can't be merged into the return statement, because buf.Bytes is called first!
170 return buf.Bytes(), err