Http: how to use http.StreamedRequest to download file?

Created on 24 Oct 2018 · 8Comments · Source: dart-lang/http

how to use http.StreamedRequest to download file?

Source

Apollo2011

Most helpful comment

StreamedRequest is used for POST requests where you are uploading a stream of bytes. I don't think it will help you here.

If you want to stream a download you're interested in StreamedResponse instead - this is assuming you _don't_ want it all in memory at once and want to write it to the file as it comes in.

void downloadByHttp() async {
  var client = http.Client();
  var request = http.Request("GET", url);
  var response = await client.send(request);
  var sink = file.openWrite();
  await response.stream.pipe(sink);
  sink.close();
}

but can not return to the download data from time to time

You can open the file again and read it if you need the data back in memory. Though if this is the case you already had it in memory once...

Future<List<int>> downloadByHttp() async {
  var file = new File("Http_Download.mp3");
  if(file.existsSync()) file.deleteSync();
  var ios = file.openWrite(mode: FileMode.APPEND);
  var response = await http.get(url);
  var bytes = response.bodyBytes;
  ios.add(bytes);
  ios.close();
  return bytes; // Caller can do whatever it needs with these bytes without rereading the file
}

As @zoechi mentioned, this type of question is better handled on stack overflow.

natebosch on 24 Oct 2018

👍6

All 8 comments

https://stackoverflow.com/questions/51195648/how-do-i-use-streamedrequest-in-dart-http-library-to-upload-a-file might help

zoechi on 24 Oct 2018

🎉1

https://stackoverflow.com/questions/51195648/how-do-i-use-streamedrequest-in-dart-http-library-to-upload-a-file might help
this is upload-a-file!!! I need download file

Apollo2011 on 24 Oct 2018

You get a StreamedResponse for the download.
Your question might be incorrect. Perhaps you want a StreamedResponse instead of StreamedRequest, but the link shows that as well.

zoechi on 24 Oct 2018

You get a StreamedResponse for the download.
Your question might be incorrect. Perhaps you want a StreamedResponse instead of StreamedRequest, but the link shows that as well.

this link is for upload-a-file! ok!
I am using StreamedResponse, but the result is not returned

Apollo2011 on 24 Oct 2018

I'd suggest you create a new StackOverflow question with more details.

zoechi on 24 Oct 2018

I'd suggest you create a new StackOverflow question with more details.

void downloadByHttp() {
  var file = new File("Http_Download.mp3");
  if(file.existsSync()) {
    file.deleteSync();
  }
  IOSink ios = file.openWrite(mode: FileMode.APPEND);
  Http.get(url)
      .then((Http.Response response) {
    ios.add(response.bodyBytes);
  }).whenComplete(() => ios.close());
}

The above can be downloaded successfully, but can not return to the download data from time to time, I looked at the data and found that StreamedRequest can be implemented, with StreamedRequest how to achieve the download?

Apollo2011 on 24 Oct 2018

StreamedRequest is used for POST requests where you are uploading a stream of bytes. I don't think it will help you here.

If you want to stream a download you're interested in StreamedResponse instead - this is assuming you _don't_ want it all in memory at once and want to write it to the file as it comes in.

void downloadByHttp() async {
  var client = http.Client();
  var request = http.Request("GET", url);
  var response = await client.send(request);
  var sink = file.openWrite();
  await response.stream.pipe(sink);
  sink.close();
}

but can not return to the download data from time to time

You can open the file again and read it if you need the data back in memory. Though if this is the case you already had it in memory once...

Future<List<int>> downloadByHttp() async {
  var file = new File("Http_Download.mp3");
  if(file.existsSync()) file.deleteSync();
  var ios = file.openWrite(mode: FileMode.APPEND);
  var response = await http.get(url);
  var bytes = response.bodyBytes;
  ios.add(bytes);
  ios.close();
  return bytes; // Caller can do whatever it needs with these bytes without rereading the file
}

As @zoechi mentioned, this type of question is better handled on stack overflow.

natebosch on 24 Oct 2018

👍6

Just wondering, how can we set to download bigger chunks? currently i only am getting around 2k bytes per chunk. i wish to increase it like 100k or 500k bytes