Android with Retrofit2 OkHttp3 - Multipart POST Error

Question

I am using Retrofit2 with OkHttp on Android for HTTP request. Here I am doing a POST request with document upload. I ran into error below:

D/OkHttp: <-- 5         


        

Answer 1

After referring to Retrofit 2 can't upload a file with two additional separate string parameters , I implemented according to @TommySM suggestion. I got my problem solved with this:

// create RequestBody instance from file
RequestBody requestFile = RequestBody.create(
            mediaType,
            myFile);

// MultipartBody.Part is used to send also the actual file name
MultipartBody.Part file = MultipartBody.Part.createFormData(
            "documentImage",
            myFile.getName(),
            requestFile);

// add another part within the multipart request
RequestBody token = RequestBody.create(
            MediaType.parse("text/plain"),   // Fixed here
            //okhttp3.MultipartBody.FORM,    => PROBLEMATIC
            userID);

RequestBody docType = RequestBody.create(
            MediaType.parse("text/plain"),   // Fixed here
            //okhttp3.MultipartBody.FORM,    => PROBLEMATIC
            docTypeStr);

// token, documentType, file
this.call = driveWealthApi.addDocument(token, docType, file);

Those String parameter should be specified as Content-Type: text/plain rather than Content-Type: multipart/form-data.

See screenshots for details:

1) Problematic POST

2) Correct POST