+type ClientEvent struct {
+ RequestSpec RequestSpec
+ Bytes []byte
+ Err error
+}
+
+func (ws *Client) Cancel(r RequestSpec) {
+ ws.requests[r].cancel()
+}
+
+func (ws *Client) Request(r RequestSpec) {
+ ctx, cancel := context.WithCancel(context.Background())
+ var requestParts []requestPart
+ if !ws.FileIndex.Locate(r, func(i int, e segments.Extent) bool {
+ req, err := NewRequest(ws.Url, i, ws.Info, e.Start, e.Length)
+ if err != nil {
+ panic(err)
+ }
+ req = req.WithContext(ctx)
+ part := requestPart{
+ req: req,
+ result: make(chan httpRequestResult, 1),
+ e: e,
+ }
+ go func() {
+ resp, err := ws.HttpClient.Do(req)
+ part.result <- httpRequestResult{
+ resp: resp,
+ err: err,
+ }
+ }()
+ requestParts = append(requestParts, part)
+ return true
+ }) {
+ panic("request out of file bounds")
+ }
+ if ws.requests == nil {
+ ws.requests = make(map[RequestSpec]request)
+ }
+ ws.requests[r] = request{cancel}
+ go func() {
+ b, err := readRequestPartResponses(requestParts)
+ ws.Events <- ClientEvent{
+ RequestSpec: r,
+ Bytes: b,
+ Err: err,
+ }
+ }()
+}
+
+func recvPartResult(buf io.Writer, part requestPart) error {
+ result := <-part.result
+ if result.err != nil {
+ return result.err
+ }
+ defer result.resp.Body.Close()
+ if part.e.Start != 0 && result.resp.StatusCode != http.StatusPartialContent {
+ return fmt.Errorf("expected partial content response got %v", result.resp.StatusCode)
+ }
+ copied, err := io.Copy(buf, result.resp.Body)
+ if err != nil {
+ return err
+ }
+ if copied != part.e.Length {
+ return fmt.Errorf("got %v bytes, expected %v", copied, part.e.Length)
+ }
+ return nil