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Fix(service): flatten memory usage of downloads (sacrificing download progress indication).

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Millesimus 2022-11-07 15:42:46 +01:00
parent bb6b342d82
commit bedd46756d
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1 changed files with 46 additions and 13 deletions
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59
lib/service/httpfiletransfer/httpfiletransfer.dart
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@ -357,22 +357,55 @@ class HttpFileTransferService {
final tempDir = await getTemporaryDirectory();
downloadPath = pathlib.join(tempDir.path, filename);
}
dio.Response<dynamic>? response;
final dio.Response<dio.ResponseBody>? response;
try {
response = await dio.Dio().downloadUri(
Uri.parse(job.location.url),
downloadPath,
onReceiveProgress: (count, total) {
final progress = count.toDouble() / total.toDouble();
sendEvent(
ProgressEvent(
id: job.mId,
progress: progress == 1 ? 0.99 : progress,
),
);
},
response = await dio.Dio().get<dio.ResponseBody>(
job.location.url,
options: dio.Options(
responseType: dio.ResponseType.stream,
),
);
final downloadStream = response.data?.stream;
if ( downloadStream != null) {
final totalFileSizeString = response.headers['Content-Length']?.first;
final totalFileSize = int.parse(totalFileSizeString!);
final file = File(downloadedPath);
// Since acting on downloadStream events like to fire progress events
// causes memory spikes relative to the file size, I chose to listen to
// the created file instead. This does not cause memory spikes, but see
// below.
final fileSink = file.openWrite(mode: FileMode.writeOnlyAppend);
file.watch().listen((FileSystemEvent event) {
if (event is FileSystemCreateEvent || event is FileSystemModifyEvent) {
final fileSize = file.lengthSync();
final progress = fileSize / totalFileSize;
sendEvent(
ProgressEvent(
id: job.mId,
progress: progress == 1 ? 0.99 : progress,
),
);
}
});
// TODO(Unknown): Find some way to pause execution until the download
// has finished. Because now, ProgressEvents are sent when the job is
// already deleted. Below, a list of solutions I tried (for both this
// problem and the problem I tried to solve with this workaround).
downloadStream.listen(fileSink.add); // .onDone would cause memory spikes
// while (! downloadStream.isEmpty) causes memory spikes
// while (file.lengthSync() / totalFileSize != 1) causes memory spikes
// using a controller on downloadStream causes memory spikes
// using a controller and piping causes memory spikes
// fileSink.addStream(downloadStream) causes memory spikes
}
} on dio.DioError catch(err) {
// TODO(PapaTutuWawa): React if we received an error that is not related to the
// connection.