google app engine - Store image to Blobstore from android client and retrieve blobkey and upload url to store in Datastore. - GAE

Question

In my Android application, I want to upload image to the Blobstore, then retrieve an Upload url and the image's Blobkey, so I can store the Blobkey in the DataStore.

I've tried this code, but my image isn't uploading:

Servlet (Return upload url)

BlobstoreService blobstoreService = BlobstoreServiceFactory
            .getBlobstoreService();
public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws IOException {

        UploadOptions uploadOptions = UploadOptions.Builder
                .withGoogleStorageBucketName("photobucket11")
                .maxUploadSizeBytes(1048576);
        String blobUploadUrl = blobstoreService.createUploadUrl("/upload",
                uploadOptions);

        // String blobUploadUrl = blobstoreService.createUploadUrl("/uploaded");

        resp.setStatus(HttpServletResponse.SC_OK);
        resp.setContentType("text/plain");

        PrintWriter out = resp.getWriter();
        out.print(blobUploadUrl);

    }

    public void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws IOException {
        doGet(req, resp);
    }

Code : Android client

Bitmap bmp = BitmapFactory.decodeFile(imagePath);
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                bmp.compress(CompressFormat.JPEG, 75, out);
                byte[] imgByte = out.toByteArray();
                String encodedImage = Base64.encodeToString(imgByte,
                        Base64.DEFAULT);

                HttpClient httpClient = new DefaultHttpClient();                    
                HttpGet httpGet = new HttpGet(
                        "app-url/ImgUpload");
                HttpResponse response = httpClient.execute(httpGet);
                HttpEntity urlEntity = response.getEntity();
                InputStream in = urlEntity.getContent();
                String str = "";
                while (true) {
                    int ch = in.read();
                    if (ch == -1)
                        break;
                    str += (char) ch;
                }

This will return upload url in form of /_ah/upload/akjdhjahdjaudshgaajsdhjsdh which I can use to store the image.

This code uses the url to store the image:

httpClient = new DefaultHttpClient();
                HttpPost postRequest = new HttpPost(str);
                ByteArrayBody bab = new ByteArrayBody(imgByte, "forest.jpg");

                MultipartEntity reqEntity = new MultipartEntity(
                        HttpMultipartMode.BROWSER_COMPATIBLE);

                reqEntity.addPart("uploaded", bab);
                reqEntity.addPart("photoCaption", new StringBody("sfsdfsdf"));
                postRequest.setEntity(reqEntity);
                response = httpClient.execute(postRequest);

                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(
                                response.getEntity().getContent(), "UTF-8"));
                String sResponse;
                StringBuilder s = new StringBuilder();

                while ((sResponse = reader.readLine()) != null) {
                    s = s.append(sResponse);
                }

Here, if I check value of the String s, it shows null. That means it is returning a null response. I don't know what the problem is with this code. Please guide me to solve this problem.

Answer 1

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