Upload multiple files from Flutter app to Net 5 server returns 400 request

Question

I keep getting 400 bad request saying that my file is missing yet when i look at the request i can see all the required files.

Flutter code:

 Future<bool> uploadArtefacts(String objectId, String objectType, List<Uint8List> artefacts) async {
    var request = http.MultipartRequest(
        'POST', Uri.parse(uriString));

    for (var artefact in artefacts) {
      request.files.add(http.MultipartFile.fromBytes('Artefacts', artefact));
    }

    request.fields['objectType'] = objectType;
    request.fields['objectId'] = objectId;
    try {
      var streamedResponse = await request.send();
      var response = await http.Response.fromStream(streamedResponse);
      if (response.statusCode == 204) {
        return true;
      }
    } catch (e) {
      log(e.toString());
    }

    return false;
  }

My controller

[HttpPost]
public async Task<IActionResult> UploadArtefact([FromForm] ArtefactDTO artefactDTO)
{
   if (!ModelState.IsValid)
   return BadRequest(ModelState);
   /// omitted for brevity
    
   return NoContent();
}

ArtefactDTO

public record ArtefactDTO(
      [Required]
      string ObjectType,
      Guid ObjectId,
      [Required]
      List<IFormFile> artefacts,
      string Description);

Request output

Response

"errors":{"artefacts":["The artefacts field is required."]}

Answer 1

For some reason Multipart class wasn't creating full formed multipart files using the fromBytes method.

Resolved it by changing it to fromPath, it worked fine.