Upload file to server

api.dart

import 'package:http/http.dart' as http;
import 'package:http_parser/http_parser.dart';

Future<http.Response> uploadFile(
  String url, 
  Map<String, String> headers, 
  Map<String, String> fields, 
  String fileName, 
  List<int> fileBytes) async {
  var request = new http.MultipartRequest("POST", Uri.parse(url));
  request.files.add(http.MultipartFile.fromBytes(
    'file',
    fileBytes,
    contentType: MediaType('application', 'octet-stream'),
    filename: fileName));
  fields.forEach((k, v) => request.fields[k] = v);
  request.headers.addAll(headers);
  var streamedResponse = await request.send();
  return await http.Response.fromStream(streamedResponse);
}