Sending a C# multipart upload request to google drive

Question

I am trying to create a multipart upload request from C# to upload a small file to Google Drive as per https://developers.google.com/drive/v3/web/multipart-upload

        using (var client = new HttpClient())
        {
            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", access_token);

            //api endpoint
            var apiUri = new Uri("https://www.googleapis.com/upload/drive/v3/files?uploadType=multipart");

            // read the image content 
            var imageBinaryContent = new ByteArrayContent(fileBytes);
            imageBinaryContent.Headers.Add("Content-Type", "image/jpeg");

            // prepare the metadata content
            string metaContent = "{\"name\":\"myObject\"}";
            byte[] byteArray = Encoding.UTF8.GetBytes(metaContent);
            var metaStream = new ByteArrayContent(byteArray);
            metaStream.Headers.Add("Content-Type", "application/json; charset=UTF-8");

            // create the multipartformdata content, set the headers, and add the above content
            var multipartContent = new MultipartFormDataContent();
            multipartContent.Headers.Remove("Content-Type");
            multipartContent.Headers.TryAddWithoutValidation("Content-Type", "multipart/form-data; boundry=myboundry---");
            multipartContent.Add(metaStream);
            multipartContent.Add(imageBinaryContent);


            HttpResponseMessage result = await client.PostAsync(apiUri, multipartContent);

        }

But I can't seem to get it working. This code works fine for simple uploads to Drive:

        using (var client = new HttpClient())
        {
            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", access_token);

            //api endpoint
            var apiUri = new Uri("https://www.googleapis.com/upload/drive/v3/files?uploadType=media");


            // read the image content 
            var imageBinaryContent = new ByteArrayContent(fileBytes);
            imageBinaryContent.Headers.Add("Content-Type", "image/jpeg");


            HttpResponseMessage result = await client.PostAsync(apiUri, imageBinaryContent);

        }

Answer 1

Two things jump out:

1. You misspelled the word boundary in boundry=myboundry.
2. Also make sure Content-Type is multipart/related.

Answer 2

For those trying this out i .net core, here's my code:

public async Task UploadFile(Stream stream, string filename)
{
    var accessToken = "";

    using var client = _httpClientFactory.CreateClient();
    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);

    var metaContent = JsonContent.Create(new { name = filename });
    var streamContent = new StreamContent(stream);
    var multipart = new MultipartContent { metaContent, streamContent };
    streamContent.Headers.ContentType = new MediaTypeHeaderValue(MediaTypeNames.Application.Octet);
    streamContent.Headers.ContentLength = stream.Length;
    var result = await client.PostAsync("https://www.googleapis.com/upload/drive/v3/files?uploadtype=multipart", multipart);
}