Implented FLAC streaming under Safari

README.md

@@ -17,6 +17,7 @@ Radio streamer ([kawa](https://github.com/Luminarys/kawa) drop-in compatible).
 * Can read and apply ReplayGain tags, or normalize audio loudness.
 * Can have audio sources over HTTP(s) URLs on `path` property, and supports seeking.
 * Precise metadata and timing information packet stream, trigger via `x-audio-packet-stream: 1` HTTP header.
+* Workaround to allow FLAC streaming under Safari
 
 ## Dependencies
 ### Go >= 1.18

queue.go

@@ -450,6 +450,36 @@ func (q *Queue) HandleRadioRequest(writer http.ResponseWriter, request *http.Req
 			rangeHeader := request.Header.Get("range")
 			if rangeHeader != "" && rangeHeader != "bytes=0-" {
 				//TODO: maybe should fail in case bytes are requested
+
+				if strings.Index(request.UserAgent(), " Safari/") != -1 && mount.MimeType == "audio/flac" {
+					//Safari special case, fake Range check so it decodes afterwards.
+					//Safari creates a request with Range for 0-1, specifically for FLAC, and expects a result supporting range. Afterwards it requests the whole file.
+					//However the decoder is able to decode FLAC livestreams. If we fake the initial range response, then afterwards serve normal responses, Safari will happily work.
+					//TODO: remove this AS SOON as safari works on its own
+					//safariLargeFileValue arbitrary large value, cannot be that large or iOS Safari fails.
+					safariLargeFileValue := 1024 * 1024 * 1024 * 1024 * 16 // 16 TiB
+
+					if rangeHeader == "bytes=0-1" {
+						//first request
+						writer.Header().Set("Accept-Ranges", "bytes")
+						writer.Header().Set("Content-Range", fmt.Sprintf("bytes 0-1/%d", safariLargeFileValue)) //64 TiB max fake size
+						writer.Header().Set("Content-Length", "2")
+						writer.WriteHeader(http.StatusPartialContent)
+						writer.Write([]byte{'\x00', '\x00'})
+						return
+					} else if rangeHeader == fmt.Sprintf("bytes=0-%d", safariLargeFileValue-1) {
+						//second request, serve status 200 to keep retries to a minimum
+						writer.Header().Set("Content-Length", fmt.Sprintf("%d", safariLargeFileValue))
+						writer.WriteHeader(http.StatusOK)
+					} else if strings.HasPrefix(rangeHeader, "bytes=") && strings.HasSuffix(rangeHeader, fmt.Sprintf("-%d", safariLargeFileValue-1)) {
+						//any other requests, these should fail
+						writer.Header().Set("Content-Range", fmt.Sprintf("bytes %s/%d", strings.TrimPrefix(rangeHeader, "bytes="), safariLargeFileValue))
+						writer.Header().Set("Accept-Ranges", "bytes")
+						writer.WriteHeader(http.StatusRequestedRangeNotSatisfiable)
+						return
+					}
+
+				}
 			}
 
 			bitrate := 0