base64 encoded PNG to Blob - blob

Question

I am fiddling around with creating a Blob out of a base64 encoded PNG...
final FormData formData = new FormData();
final String base64Image = "data:image/png;base64,iVBORw0K<reduced the data.....>gg==";
final Blob blob = new Blob([base64Image],"image/png");
formData.append('file', blob, "android.png");
req.send(formData);
I don't know what I a doing wrong but the contents of blob is something but not the png I would like it to be.
thx in advance...
[Update]
final FormData formData = new FormData();
final String base64Image = "iVBORw0KGgo<...reduce data...>kJggg==";
// BTW: I used the Base64 from dart-sdk/io/base64.dart
final List<int> intList = Base64.decode(base64Image);
final Int8Array int8array = new Int8Array.fromList(intList);
final String atobString = window.atob(base64Image);
// Does not work
// final Blob blob = new Blob([atobString]);
// The same...
// final Blob blob = new Blob([int8array]);
formData.append('file', blob, "android.png");
//formData.append('new-filename', "icon-share.png");
req.send(formData);
I think the number of bytes generated by Base64.decode are OK. The filesize was 1003 bytes and decoding also produces 1003 bytes.
[Update 2]
Here is the source I am talking about:
https://github.com/MikeMitterer/AndroidIconGenerator.DART/blob/master/test/src/restserver.dart

Answer 1

OK, here is the answer to my own question:
import 'dart:convert'
...
test(' -> Upload File to REST-Server', () {
final HttpRequest req = new HttpRequest();
loadEnd(HttpRequest request) {
if (request.readyState == HttpRequest.DONE) {
switch(request.status) {
case HttpStatus.HTTP_200_OK:
expect(response['path'].endsWith("android.png"),true);
break;
case HttpStatus.HTTP_0_COMMUNICATION_FAILED:
expect(request.status,HttpStatus.HTTP_200_OK);
break;
default:
expect(request.status,HttpStatus.HTTP_200_OK);
break;
}
}
}
req.open("POST", uriprovider.forUpload().toString());
// REST returns JSON Data
req.setRequestHeader('Accept', 'application/json');
req.onLoadEnd.listen(expectAsync1((ProgressEvent e) => loadEnd(req)));
final FormData formData = new FormData();
final String base64Image = "data:image/png;base64,iVBORw0KG<code reduce for sample>RU5ErkJggg==";
final String raw = "iVBORw0KG<code reduce for sample>RU5ErkJggg==";
final String contenttype = "image/png";
// Base64 is a modified version of dart-sdk/lib/io/base64.dart
final List<int> intList = BASE64.decode(raw);
final Int8Array int8array = new Int8Array.fromList(intList);
// Converting to Uint8Array brought the solution!
final Uint8Array uint8array = new Uint8Array(intList.length);
// does not work!
//var binary = window.atob(raw);
final Blob blob = new Blob([uint8array]);
formData.append('file', blob, "android.png");
req.send(formData);
});
Thanks to everyone pushing me in the right direction!

Answer 2

Need decode base64 (i.e. atob) url, before you encode to Blob. It's easy! Try it!