Odtnhj

I am trying to send an image via a POST request from an Android app to a Heroku webserver. In the webserver, I want to retrieve the image from the request, modify and then send the modified image back as a response.

However, my current code returns an an IOException in the webserver saying

java.io.IOException: Missing content for multipart request
org.eclipse.jetty.util.MultiPartInputStreamParser.parse(MultiPartInputStreamParser.java:496)org.eclipse.jetty.util.MultiPartInputStreamParser.getParts(MultiPartInputStreamParser.java:405)

I checked and the userImageFile does exist in the Android app at least.

This is my code in the Android app (using OkHttp).

 //Creating file with the bitmap gotten from the user
 String path = this.getFilesDir().getAbsolutePath();
 File userImageFile = new File(path + "/image.png");
 userImageFile.createNewFile();
 FileOutputStream fop = new FileOutputStream(userImageFile, false);
 bitmap.compress(Bitmap.CompressFormat.PNG, 100, fop);
 fop.flush();
 fop.close();

 OkHttpClient okHttpClient = new OkHttpClient();
 String url = "https://my-heroku-app-url-here.com/imageConvert";
 RequestBody body = new MultipartBody.Builder()
 .setType(MultipartBody.FORM)
 .addFormDataPart("image", userImageFile.getName(),
 RequestBody.create(MediaType.parse("image/png"), userImageFile))
 .build();

 Request request = new Request.Builder()
 .url(url)
 .post(body)
 .build();

 Response response = okHttpClient.newCall(request).execute();

And this is my code for the Heroku webserver (using the Spark framework).

post("/imageConvert", (request, response) -> 
 byte body = request.bodyAsBytes();
 request.attribute("org.eclipse.jetty.multipartConfig", new MultipartConfigElement("/temp"));
 BufferedImage returnImage = null;
 try (InputStream is = request.raw().getPart("image").getInputStream()) 
 BufferedImage userImage = ImageIO.read(is);
 returnImage = getDistortedImage(userImage);
 catch (IOException ex)
 return "There has been an IO Exception: n" + ex.getMessage();
 
 if(returnImage!= null)
 ImageIO.write(returnImage, "png", response.raw().getOutputStream());
 return response.raw();
 
 return "There was an unknown mistake";
 );

I think that you are consuming the request body twice. If the request contents are consumed once, then you can no longer consume the bytes / stream again just like that, without some explicit resetting mechanism.

You should remove the first statement, so that the second statement is able to consume the input stream.

1. byte body = request.bodyAsBytes(); // Remove this

2. try (InputStream is = request.raw().getPart("image").getInputStream())