Allow non-partial webseed part responses for small files

diff --git a/webseed/client.go b/webseed/client.go
index 6acf90d88098f54c3055e2dd93b250f418dded41..4e3f7317a694698b8f629c0a62a2fe69f351d298 100644 (file)
--- a/webseed/client.go
+++ b/webseed/client.go
@@ -5,6 +5,7 @@ import (
        "context"
        "fmt"
        "io"
+       "log"
        "net/http"
        "strings"
 
@@ -123,9 +124,29 @@ func recvPartResult(ctx context.Context, buf io.Writer, part requestPart) error
        }
        switch result.resp.StatusCode {
        case http.StatusPartialContent:
+               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
        case http.StatusOK:
-               if part.e.Start != 0 {
-                       return ErrBadResponse{"got status ok but request was at offset", result.resp}
+               // This number is based on
+               // https://archive.org/download/BloodyPitOfHorror/BloodyPitOfHorror.asr.srt. It seems that
+               // archive.org might be using a webserver implementation that refuses to do partial
+               // responses to small files.
+               if part.e.Start < 48<<10 {
+                       log.Printf("resp status ok but requested range [url=%q, range=%q]", part.req.URL, part.req.Header.Get("Range"))
+                       discarded, _ := io.CopyN(io.Discard, result.resp.Body, part.e.Start)
+                       if discarded != 0 {
+                               log.Printf("discarded %v bytes in webseed request response part", discarded)
+                       }
+                       _, err := io.CopyN(buf, result.resp.Body, part.e.Length)
+                       return err
+               } else {
+                       return ErrBadResponse{"resp status ok but requested range", result.resp}
                }
        default:
                return ErrBadResponse{
@@ -133,14 +154,6 @@ func recvPartResult(ctx context.Context, buf io.Writer, part requestPart) error
                        result.resp,
                }
        }
-       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
 }
 
 func readRequestPartResponses(ctx context.Context, parts []requestPart) ([]byte, error) {