post method
Implementation
Future<Map<String, dynamic>> post(
String cmd, dynamic c, MultipartFile? f) async {
if (!(c is String) && !(c is Map)) throw 'Wrong type of arguments';
Map<String, dynamic> q =
(c is String) ? {'arg': c} : c as Map<String, dynamic>;
Uri uri = Uri.parse(apiUrl + cmd);
var request = MultipartRequest(
'POST',
uri.replace(
queryParameters: q,
),
);
if (f != null) request.files.add(f);
final res = await request.send();
final r = await res.stream.bytesToString();
Map<String, dynamic> item = jsonDecode(r);
return item;
}