Android multipart POST http Request 415 Error

Question

beginner android developer here. I am trying to POST a .gpx file to my web database. However, I am receiving http response error 415. I know 415 means incorrect content type and the API that I am trying to use has this code.. Thanks for any tips!

        // Test that request has correct content type
        if (!Request.Content.IsMimeMultipartContent())
        {
            throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
        }

I was following this tutorial http://www.codejava.net/java-se/networking/upload-files-by-sending-multipart-request-programmatically .

This is my Http Request class

/**
 * This constructor initializes a new HTTP POST request with content type
 * is set to multipart/form-data
 * @param requestURL
 * @param charset
 * @throws IOException
 */
public MultipartUtility(String requestURL, String charset)
        throws IOException {
    this.charset = charset;

    // creates a unique boundary based on time stamp
    boundary = "===" + System.currentTimeMillis() + "===";

    URL url = new URL(requestURL);
    httpConn = (HttpURLConnection) url.openConnection();
    httpConn.setUseCaches(false);
    httpConn.setDoOutput(true); // indicates POST method
    httpConn.setDoInput(true);
    httpConn.setRequestMethod("POST");

    httpConn.setRequestProperty("Connection", "Keep-Alive");
    httpConn.setRequestProperty("Content-Type", // content type multipart ( FILE)
           "multipart/form-data; boundary=" + boundary);
    httpConn.setRequestProperty("Authorization", UserInfo.User.getToken());
    outputStream = httpConn.getOutputStream();
    writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
            true);
}

/**
 * Adds a form field to the request
 * @param name field name
 * @param value field value
 */
public void addFormField(String name, String value) {
    writer.append("--" + boundary).append(LINE_FEED);
    writer.append("Content-Disposition: form-data; name=\"" + name + "\"")
            .append(LINE_FEED);
    //writer.append("Content-Type: text/plain; charset=" + charset).append(LINE_FEED);
    writer.append(LINE_FEED);
    writer.append(value).append(LINE_FEED);
    writer.flush();
}

/**
 * Adds a upload file section to the request
 * @param fieldName name attribute in <input type="file" name="..." />
 * @param uploadFile a File to be uploaded
 * @throws IOException
 */
public void addFilePart(String fieldName, File uploadFile)
        throws IOException {
    String fileName = uploadFile.getName();
    writer.append("--" + boundary).append(LINE_FEED);
    writer.append(
            "Content-Disposition: form-data; name=\"" + fieldName
                    + "\"; filename=\"" + fileName + "\"");
    //Log.i("fileName",fileName);
    writer.append("Content-Type: " + "multipart/form-data; boundary=" + boundary);
    //.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
    writer.append(LINE_FEED);
    writer.flush();

    FileInputStream inputStream = new FileInputStream(uploadFile);
    byte[] buffer = new byte[4096];
    int bytesRead = -1;
    while ((bytesRead = inputStream.read(buffer)) != -1) {
        outputStream.write(buffer, 0, bytesRead);
    }
    outputStream.flush();
    inputStream.close();

    writer.append(LINE_FEED);
    writer.flush();
}

/**
 * Adds a header field to the request.
 * @param name - name of the header field
 * @param value - value of the header field
 */
public void addHeaderField(String name, String value) {
    writer.append(name + ": " + value).append(LINE_FEED);
    writer.flush();
    //Log.i("header",name + ": " + value);
}

/**
 * Completes the request and receives response from the server.
 * @return a list of Strings as response in case the server returned
 * status OK, otherwise an exception is thrown.
 * @throws IOException
 */
public List<String> finish() throws IOException {
    List<String> response = new ArrayList<String>();

    writer.append(LINE_FEED).flush();
    writer.append("--" + boundary + "--").append(LINE_FEED);
    writer.close();

    // checks server's status code first
    int status = httpConn.getResponseCode();
    if (status == HttpURLConnection.HTTP_OK) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                httpConn.getInputStream()));
        String line = null;
        while ((line = reader.readLine()) != null) {
            response.add(line);
        }
        reader.close();
        httpConn.disconnect();
    } else {
        throw new IOException("Server returned non-OK status: " + status);
    }

    return response;
}

This is my activity

        String requestURL = "url";


        try {
            MultipartUtility multipart = new MultipartUtility(requestURL, charset);

            multipart.addFilePart("filename", File);

            List<String> response = multipart.finish();

            System.out.println("SERVER REPLIED:");

            for (String line : response) {
                System.out.println(line);
            }
        } catch (IOException ex) {
            System.err.println(ex);
        }
    }

This is my response from httpbin

/*I/System.out: SERVER REPLIED:

I/System.out: {

I/System.out: "args": {},

I/System.out: "data": "",

I/System.out: "files": {

I/System.out: "FileName": "http://www.topografix.com/GPX/1/1\\" version=\\"1.0\\">\\n\\n\\r\\n"

I/System.out: },

I/System.out: "form": {},

I/System.out: "headers": {

I/System.out: "Accept-Encoding": "gzip",

I/System.out: "Authorization": "Bearer ",

I/System.out: "Content-Length": "322",

I/System.out: "Content-Type": "multipart/form-data; boundary====1488396069658===",

I/System.out: "Host": "httpbin.org",

I/System.out: "User-Agent": "Dalvik/2.1.0 (Linux; U; Android 7.0; Android SDK built for x86 Build/NYC)"

I/System.out: },

I/System.out: "json": null,

I/System.out: "origin": "50.174.210.222",

I/System.out: "url": " http://httpbin.org/post "

I/System.out: }*/

IF ANYONE ELSE IS HAVING THIS TROUBLE.. I USED RETROFIT2 TO SUCCESSFULLY UPLOAD MY FILE.

//Retrofit2 method
public void uploadFile() {

    OkHttpClient.Builder okHttpClientBuilder = new OkHttpClient.Builder();
    HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
    interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
    okHttpClientBuilder.addInterceptor(interceptor);

    okHttpClientBuilder.addInterceptor(new Interceptor() {
        @Override
        public okhttp3.Response intercept(Chain chain) throws IOException {
            okhttp3.Request original = chain.request();

            okhttp3.Request.Builder requestBuilder = original.newBuilder()
                    .header("Authorization", UserInfo.User.getToken());

            okhttp3.Request request = requestBuilder.build();
            return chain.proceed(request);
        }
    });


    MediaType MEDIA_TYPE_XML = MediaType.parse("application/xml");

    RequestBody filePart = RequestBody.create(MEDIA_TYPE_XML, gpx);

    MultipartBody.Part file = MultipartBody.Part.createFormData("Track", gpx.getName(), filePart);

    Retrofit.Builder builder = new Retrofit.Builder()
            .baseUrl("URL")
            .addConverterFactory(GsonConverterFactory.create())
            .client(okHttpClientBuilder.build());

    Retrofit retrofit = builder.build();

    UserClient client = retrofit.create(UserClient.class);

    Call<ResponseBody> call = client.uploadFile(file);
    call.enqueue(new Callback<ResponseBody>() {
        @Override
        public void onResponse(Call<ResponseBody> call, retrofit2.Response<ResponseBody> response) {
            Log.i("works", call.toString());
        }

        @Override
        public void onFailure(Call<ResponseBody> call, Throwable t) {
            Log.i("Fail", "gg");
        }
    });
}

My Interface

public interface UserClient{

@Multipart
@POST("Gpx")
Call<ResponseBody> uploadFile(
        @Part MultipartBody.Part File
        );

}

Answer 1

    public static <C> C createService(Class<C> cClass) {
        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
        OkHttpClient client = new OkHttpClient.Builder().addInterceptor(interceptor).build();
        Retrofit retrofit = new Retrofit.Builder()
                .client(client)
                .baseUrl(UrlManager.Manager.BASE_URL)
                .build();
        return retrofit.create(cClass);
    }

this code creates a factory then logs all middle ware requests. This code once called , every content with respect to the request will be log automatically in logcat. you can filter by typing okHTTp.

To use the interceptor: include compile 'com.squareup.okhttp3:logging-interceptor:3.3.1'