fix some channels not loading at all using HLS service

hls/content_m3u8.go

@@ -34,7 +34,7 @@ func handleEstablishedContentM3U8(w http.ResponseWriter, r *http.Request, cr *Co
 	switch {
 	case contentType == "application/vnd.apple.mpegurl" || contentType == "application/x-mpegurl": // M3U8 metadata
 		content := rewriteLinks(&resp.Body, prefix, cr.Channel.LinkM3u8Ref.linkRoot)
-		addHeaders(resp.Header, w.Header())
+		addHeaders(resp.Header, w.Header(), false)
 		w.WriteHeader(http.StatusOK)
 		fmt.Fprint(w, content)
 	default: // media (or anything else)

hls/content_media.go

@@ -18,7 +18,7 @@ func handleContentMedia(w http.ResponseWriter, r *http.Request, cr *ContentReque
 
 func handleEstablishedContentMedia(w http.ResponseWriter, r *http.Request, cr *ContentRequest, resp *http.Response) {
 	cr.Channel.Mux.Unlock() // So other clients can watch it too
-	addHeaders(resp.Header, w.Header())
+	addHeaders(resp.Header, w.Header(), true)
 	w.WriteHeader(resp.StatusCode)
 	io.Copy(w, resp.Body)
 	cr.Channel.Mux.Lock() // To prevent runtime error because we use 'defer' to unlock mux

hls/utils.go

@@ -126,7 +126,7 @@ func response(link string) (*http.Response, error) {
 	return nil, errors.New(link + " returned HTTP code " + strconv.Itoa(resp.StatusCode))
 }
 
-func addHeaders(from, to http.Header) {
+func addHeaders(from, to http.Header, contentLength bool) {
 	for k, v := range from {
 		switch k {
 		case "Connection":
@@ -140,7 +140,13 @@ func addHeaders(from, to http.Header) {
 		case "Date":
 			to.Set("Date", strings.Join(v, "; "))
 		case "Content-Length":
-			to.Set("Content-Length", strings.Join(v, "; "))
+			// This is only useful for unaltered media files. It should not be copied for M3U8 requests because
+			// players will not attempt to receive more bytes from HTTP server than are set here, therefore some M3U8
+			// contents would not load. E.g. CURL would display error "curl: (18) transfer closed with 83 bytes remaining to read"
+			// if set for M3U8 requests.
+			if contentLength {
+				to.Set("Content-Length", strings.Join(v, "; "))
+			}
 		}
 	}
 }