fix(crypt): fix 139cloud hack (#5178)

(cherry picked from commit 18bf64a)

Author: SeanHeuc

internal/stream/util.go

@@ -43,7 +43,7 @@ func GetRangeReadCloserFromLink(size int64, link *model.Link) (model.RangeReadCl
 				return nil, fmt.Errorf("http request failure,status: %d err:%s", response.StatusCode, err)
 			}
 			if r.Start == 0 && (r.Length == -1 || r.Length == size) || response.StatusCode == http.StatusPartialContent ||
-				checkContentRange(&response.Header, size, r.Start) {
+				checkContentRange(&response.Header, r.Start) {
 				return response.Body, nil
 			} else if response.StatusCode == http.StatusOK {
 				log.Warnf("remote http server not supporting range request, expect low perfromace!")
@@ -72,12 +72,12 @@ func RequestRangedHttp(ctx context.Context, link *model.Link, offset, length int
 }
 
 // 139 cloud does not properly return 206 http status code, add a hack here
-func checkContentRange(header *http.Header, size, offset int64) bool {
-	r, err2 := http_range.ParseRange(header.Get("Content-Range"), size)
-	if err2 != nil {
-		log.Warnf("exception trying to parse Content-Range, will ignore,err=%s", err2)
+func checkContentRange(header *http.Header, offset int64) bool {
+	start, _, err := http_range.ParseContentRange(header.Get("Content-Range"))
+	if err != nil {
+		log.Warnf("exception trying to parse Content-Range, will ignore,err=%s", err)
 	}
-	if len(r) == 1 && r[0].Start == offset {
+	if start == offset {
 		return true
 	}
 	return false

pkg/http_range/range.go

@@ -107,6 +107,27 @@ func ParseRange(s string, size int64) ([]Range, error) { // nolint:gocognit
 	return ranges, nil
 }
 
+// ParseContentRange this function parse content-range in http response
+func ParseContentRange(s string) (start, end int64, err error) {
+	if s == "" {
+		return 0, 0, ErrInvalid
+	}
+	const b = "bytes "
+	if !strings.HasPrefix(s, b) {
+		return 0, 0, ErrInvalid
+	}
+	p1 := strings.Index(s, "-")
+	p2 := strings.Index(s, "/")
+	if p1 < 0 || p2 < 0 {
+		return 0, 0, ErrInvalid
+	}
+	startStr, endStr := textproto.TrimString(s[len(b):p1]), textproto.TrimString(s[p1+1:p2])
+	start, startErr := strconv.ParseInt(startStr, 10, 64)
+	end, endErr := strconv.ParseInt(endStr, 10, 64)
+
+	return start, end, errors.Join(startErr, endErr)
+}
+
 func (r Range) MimeHeader(contentType string, size int64) textproto.MIMEHeader {
 	return textproto.MIMEHeader{
 		"Content-Range": {r.ContentRange(size)},