File Upload with Additonal Form Data to Web Api from MVC

Question

I am trying to upload a file with additional form data and post to Web API via MVC but i couldn't accomplish.

MVC Side

Firstly i got the submitted form at MVC. Here is the action for this.

    [HttpPost]
            public async Task<ActionResult> Edit(BrandInfo entity) {

                try {
                    byte[] logoData = null;
                    if(Request.Files.Count > 0) {
                        HttpPostedFileBase logo = Request.Files[0];
                        logoData = new byte[logo.ContentLength];
                        logo.InputStream.Read(logoData, 0, logo.ContentLength);
                        entity.Logo = logo.FileName;
                        entity = await _repo.Update(entity.BrandID, entity, logoData);
                    }
                    else
                        entity = await _repo.Update(entity,entity.BrandID);
                    return RedirectToAction("Index", "Brand");
                }
                catch(HttpApiRequestException e) {
// logging, etc                   
                    return RedirectToAction("Index", "Brand");
                }
            }

Below code post the Multipartform to Web API

string requestUri = UriUtil.BuildRequestUri(_baseUri, uriTemplate, uriParameters: uriParameters);
            MultipartFormDataContent formData = new MultipartFormDataContent();
            StreamContent streamContent = null;
            streamContent = new StreamContent(new MemoryStream(byteData));            
            streamContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data") {
                FileName = "\"" + fileName + "\"",
                Name = "\"filename\""
            };
            streamContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
            formData.Add(streamContent);
            formData.Add(new ObjectContent<TRequestModel>(requestModel, _writerMediaTypeFormatter), "entity");
            return _httpClient.PutAsync(requestUri, formData).GetHttpApiResponseAsync<TResult>(_formatters);

As you can see i am trying to send file data and object with same MultipartFormDataContent. I couldn't find better way to send my entity as ObjectContent. Also i am using JSON.Net Serializer

Regarding to fiddler, post seems successfull.

PUT http://localhost:12836/api/brand/updatewithlogo/13 HTTP/1.1
Content-Type: multipart/form-data; boundary="10255239-d2a3-449d-8fad-2f31b1d00d2a"
Host: localhost:12836
Content-Length: 4341
Expect: 100-continue

--10255239-d2a3-449d-8fad-2f31b1d00d2a
Content-Disposition: form-data; filename="web-host-logo.gif"; name="filename"
Content-Type: application/octet-stream

GIF89a��L������X�������wW����������xH�U�)�-�k6�������v6�������̥�v�J���������7����V:�=#�ի�I(�xf�$�������
// byte data
// byte data
'pf�Y��y�ؙ�ڹ�(�;
--10255239-d2a3-449d-8fad-2f31b1d00d2a
Content-Type: application/json; charset=utf-8
Content-Disposition: form-data; name=entity

{"BrandID":13,"AssetType":null,"AssetTypeID":2,"Logo":"web-host-logo.gif","Name":"Geçici Brand","Models":null,"SupplierBrands":null}
--10255239-d2a3-449d-8fad-2f31b1d00d2a--

Web API Side

Finally i am catching post at Web API side and trying to parse but i couldn't. Because MultipartFormDataStreamProvider's FileData and FormData collections are allways empty.

[HttpPut]
        public void UpdateWithLogo(int id) {
            if(Request.Content.IsMimeMultipartContent()) {
                var x = 1; // this code has no sense, only here to check IsMimeMultipartContent
            }  

            string root = HttpContext.Current.Server.MapPath("~/App_Data");
            var provider = new MultipartFormDataStreamProvider(root);

            try {
                // Read the form data.
                 Request.Content.ReadAsMultipartAsync(provider);

                 foreach(var key in provider.FormData.AllKeys) {
                     foreach(var val in provider.FormData.GetValues(key)) {
                         _logger.Info(string.Format("{0}: {1}", key, val));
                     }
                 }

                // This illustrates how to get the file names.
                foreach(MultipartFileData file in provider.FileData) {
                    _logger.Info(file.Headers.ContentDisposition.FileName);
                    _logger.Info("Server file path: " + file.LocalFileName);
                }               
            }
            catch(Exception e) {
                throw new HttpApiRequestException("Error", HttpStatusCode.InternalServerError, null);
            }              
        }

I hope you can help to find my mistake.

UPDATE

I also realized that, if i comment out StreamContent or ObjectContent and only add StringContent, still i can't get anything from MultipartFormDataStreamProvider.

Answer 1

Finally i resolved my problem and it was all about async :)

As you can see at API action method i had called ReadAsMultipartAsync method synchrously but this was a mistake. I had to call it with ContinueWith so after i changed my code like below my problem solved.

var files = Request.Content.ReadAsMultipartAsync(provider).ContinueWith<HttpResponseMessage>(task => {
                    if(task.IsFaulted)
                        throw task.Exception;
// do additional stuff
});