Uploading chunked video file to cloudinary in flutter - flutter

Question

I am trying to upload a video file thats greater than 100mb to cloudinary in chunks.
I have created a class that splits the video file and uploads each chunk.
import 'dart:async';
import 'dart:io';
import 'dart:math';
import 'package:http/http.dart' as http;
import 'network.dart';
class ChunkedUploader {
final http.Client _client;
ChunkedUploader(this._client);
Future<http.StreamedResponse> upload({
String url,
File file,
Map<String, dynamic> body,
int maxChunkSize,
int uniqueId,
Function(double) onUploadProgress,
}) =>
UploadRequest(
_client,
url: url,
file: file,
body: body,
maxChunkSize: maxChunkSize,
uniqueId: uniqueId,
onUploadProgress: onUploadProgress,
).upload();
}
class UploadRequest {
final http.Client client;
final String url;
final File file;
final Map<String, dynamic> body;
final int uniqueId;
final Function(double) onUploadProgress;
int _fileSize;
int _maxChunkSize;
UploadRequest(
this.client, {
this.url,
this.file,
this.body,
this.uniqueId,
this.onUploadProgress,
int maxChunkSize,
}) {
_fileSize = file.lengthSync();
_maxChunkSize = min(_fileSize, maxChunkSize ?? _fileSize);
}
Future<http.StreamedResponse> upload() async {
http.StreamedResponse finalResponse;
for (int i = 0; i < _chunksCount; i++) {
final start = _getChunkStart(i);
final end = _getChunkEnd(i);
final chunkStream = _getChunkStream(start, end);
MultipartRequest request = MultipartRequest(
"POST",
Uri.parse(url),
onProgress: (int bytes, int total) {
_updateProgress(i, bytes, total);
},
);
//Add the headers
request.headers.addAll(_getHeaders(start, end));
//Add the body
request.fields.addAll(body);
//Get the file
http.MultipartFile multipartFile =
http.MultipartFile("file", chunkStream, end - start);
request.files.add(multipartFile);
//Send the file
http.StreamedResponse response =
await client.send(request).catchError((error) {
throw error;
});
print(response);
finalResponse = response;
}
return finalResponse;
}
Stream<List<int>> _getChunkStream(int start, int end) =>
file.openRead(start, end);
// Updating total upload progress
_updateProgress(int chunkIndex, int chunkCurrent, int chunkTotal) {
int totalUploadedSize = (chunkIndex * _maxChunkSize) + chunkCurrent;
double totalUploadProgress = (totalUploadedSize / _fileSize) * 100;
this.onUploadProgress?.call(totalUploadProgress);
}
// Returning start byte offset of current chunk
int _getChunkStart(int chunkIndex) => chunkIndex * _maxChunkSize;
// Returning end byte offset of current chunk
int _getChunkEnd(int chunkIndex) =>
min((chunkIndex + 1) * _maxChunkSize, _fileSize);
// Returning a header map object containing Content-Range
// https://tools.ietf.org/html/rfc7233#section-2
Map<String, String> _getHeaders(int start, int end) => {
'X-Unique-Upload-Id': "$uniqueId",
'Content-Range': 'bytes $start-${end - 1}/$_fileSize',
};
// Returning chunks count based on file size and maximum chunk size
int get _chunksCount => (_fileSize / _maxChunkSize).ceil();
}
When making the request i am getting a response of
Status code - 500
Body - {
“error” : {
“message” : "General Error”
}
}
I have been in touch with cloudinary and they have found the request and said that it is failing with the error: invalid byte sequence in UTF-8.
Any help would be appreciated