Unable to format file to upload to Cloudinary - flutter

Question

I am trying to send an image from Flutter application to Cloudinary using Uploading with a direct call to the REST API,but getting this error:
{"error":{"message":"Invalid file parameter. Make sure your file parameter does not include '[]'"}}
I tried to encode image as an array of bytes, base64Encode but none of that worked, I followed this documentation.
Does anybody know how to encode the file so I can send it?
thanks
EDIT:
#override
Future<void> getImageSignature(File image) async {
return await _callWithExceptionWrap(() async {
if (image != null) {
DateTime dateTime = DateTime.now();
String url = _formatUrlForUploadSignature();
Dio dio = NetworkUtils.createDioConnection();
debugPrint('REQUEST TO SERVER');
Response serverResponse = await dio.post(url, data: {
"paramsToSign": {
'public_id': 'public_id_654',
"timestamp": dateTime.millisecondsSinceEpoch,
"upload_preset": "signed_preset",
"source": "uw",
}
});
debugPrint('REQUEST TO CLOUDINARY');
String signature = serverResponse.data['signature'];
List<int> bytes = image.readAsBytesSync();
var base64Image = base64Encode(bytes);
Map<String, dynamic> map = {
'api_key': _CLOUDINARY_API_KEY,
'public_id': 'public_id_654',
'signature': signature,
'source': 'uw',
'timestamp': dateTime.millisecondsSinceEpoch,
'upload_preset': 'signed_preset',
'file': base64Image,
};
debugPrint('json : ${map}');
// FormData formData = new FormData.fromMap(map);
Response cloudinaryResponse = await dio.post(_CLOUDINARY_URL, data: map);
debugPrint('*************************** Cloudinary response : ${cloudinaryResponse.data}');
}
});
The signature is ok, since I am not getting 401 error(signature I am receiving from the server.
here is the cloudinary url:
_CLOUDINARY_URL = 'https://api.cloudinary.com/v1_1//image/upload';

Answer 1

That is not correct api to use on a public client (Mobile app), you shouldn't be exposing your API_KEY and API_SECRET. Check out this package instead, which uses the correct api to upload files https://pub.dev/packages/cloudinary_public

Answer 2

The package Olajide suggested would only work for Unsigned uploads. For anyone that wants to use Signed uploads use this package https://pub.dev/packages/cloudinary_sdk