Retrofit 2 can't upload a file with two additional separate string parameters

Question

Read edit at bottom of the question for possible alternative solution until the solution is found.

This is a successful post file with two parameters using POSTMan. I am trying to do the same with retrofit but receive BadRequest.

PostMan Settings:

Chrome Network Post Details:

Now here is how I am doing this in Android but failing:

Retrofit Service Interface:

@Multipart
@POST("jobDocuments/upload")
Call<ResponseBody> upload(@Part("file") MultipartBody.Part file,@Part("folder") MultipartBody.Part folder,@Part("name") MultipartBody.Part name);

This is my @Background method to run the network request with above service generated

CustDataClient service =
            ServiceGenerator.createService(CustDataClient.class);
    File file = new File(fileUri.getPath());
    // create RequestBody instance from file
    RequestBody requestFile =
            RequestBody.create(MediaType.parse("multipart/form-data"), file);

    MultipartBody.Part fileData =
            MultipartBody.Part.createFormData("file", fileName, requestFile);
    MultipartBody.Part folder =
            MultipartBody.Part.createFormData("folder", "LeadDocuments");
    MultipartBody.Part name =
            MultipartBody.Part.createFormData("name", fileName);
    // finally, execute the request
    Call<ResponseBody> call = service.upload(fileData,folder,name);
    try {
        Response<ResponseBody> rr = call.execute();
        ResponseBody empJobDocsResult = rr.body();//Bad Request here :(
        Log.v("Upload", "success");
    } catch (Exception ex) {
        Log.e("Upload error:", ex.getMessage());
    }

Here is my Web Api Method:

 [Route("upload")]
    [HttpPost]
    public IHttpActionResult Upload()
    {
        if (HttpContext.Current.Request.Files.AllKeys.Any())
        {
            // Get the uploaded image from the Files collection
            var httpPostedFile = HttpContext.Current.Request.Files["file"];

            if (httpPostedFile != null)
            {
                // Validate the uploaded image(optional)
                var folder = HttpContext.Current.Request.Form["folder"];
                var fileName = HttpContext.Current.Request.Form["name"];
                fileName = string.IsNullOrEmpty(fileName) ? httpPostedFile.FileName : fileName;
                // Get the complete file path
                var fileSavePath = Path.Combine(HttpContext.Current.Server.MapPath("~/Files/" + folder), fileName);

                // Save the uploaded file to "UploadedFiles" folder
                httpPostedFile.SaveAs(fileSavePath);

                return Ok(new OkMessage { Message = "File uploaded successfully", Path = "/Files/" + folder + "/" + fileName });
            }
        }

        return BadRequest("File not uploaded");
    }

Please help where I am wrong and how to achieve this, is there any easy alternative to retrofit?

[Edit] This code is working successfully, Thanks to koush/ion:

Ion.with(getContext())
                            .load("POST", "http://www.dgheating.com/api/jobDocuments/upload")
                            .setMultipartParameter("folder", "LeadDocuments")
                            .setMultipartParameter("name", fileName)
                            .setMultipartFile("file", new File(imagePath))
                            .asJsonObject()
                            .setCallback(...);

Answer 1

I faced similar issue here: Android with Retrofit2 OkHttp3 - Multipart POST Error

I got my problem solved after taking @TommySM suggestion. If is still unclear to you, I think this is the solution:

@Multipart
@POST("jobDocuments/upload")
Call<ResponseBody> upload(
    @Part MultipartBody.Part file,
    @Part("folder") RequestBody folder,
    @Part("name")   RequestBody name);

File file = new File(fileUri.getPath());

// Assume your file is PNG
RequestBody requestFile =
        RequestBody.create(MediaType.parse("image/png"), file);

MultipartBody.Part fileData =
        MultipartBody.Part.createFormData("file", fileName, requestFile);

RequestBody folder = RequestBody.create(
        MediaType.parse("text/plain"),
        "LeadDocuments");

RequestBody name = RequestBody.create(
        MediaType.parse("text/plain"),
        fileName);

// finally, execute the request
Call<ResponseBody> call = service.upload(fileData, folder, name);

The important part is to use MediaType.parse("text/plain") for MediaType of String parameter (I believe your case is: folder & name parameter), using okhttp3.MultipartBody.FORM is a mistake.

See these screenshots for the comparison:

1) Problematic POST

2) Correct POST