Azure storage block blob upload from android example

Question

I am using the following code from an android application to upload a blob to Azure Blob Storage. Note: the sasUrl parameter below is a signed url acquired from my web service :

    // upload file to azure blob storage
    private static Boolean upload(String sasUrl, String filePath, String mimeType) {
        try {
            // Get the file data
            File file = new File(filePath);
            if (!file.exists()) {           
                    return false;
            }

            String absoluteFilePath = file.getAbsolutePath();

            FileInputStream fis = new FileInputStream(absoluteFilePath);
            int bytesRead = 0;
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            byte[] b = new byte[1024];
            while ((bytesRead = fis.read(b)) != -1) {
                bos.write(b, 0, bytesRead);
            }
            fis.close();
            byte[] bytes = bos.toByteArray();
            // Post our image data (byte array) to the server
            URL url = new URL(sasUrl.replace("\"", ""));
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setDoOutput(true);
            urlConnection.setConnectTimeout(15000);
            urlConnection.setReadTimeout(15000);
            urlConnection.setRequestMethod("PUT");
            urlConnection.addRequestProperty("Content-Type", mimeType);
            urlConnection.setRequestProperty("Content-Length", "" + bytes.length);
            urlConnection.setRequestProperty("x-ms-blob-type", "BlockBlob");
            // Write file data to server
            DataOutputStream wr = new DataOutputStream(urlConnection.getOutputStream());
            wr.write(bytes);
            wr.flush();
            wr.close();
            int response = urlConnection.getResponseCode();
            if (response == 201 && urlConnection.getResponseMessage().equals("Created")) {
                return true;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

The code is working fine for small blobs but when a blob reaches a certain size depending on the phone I am testing with, I start to get out of memory exceptions. I would like to split the blobs and upload them in blocks. However, all the examples I find on the web are C# based and are using the Storage Client library. I am looking for a Java/Android example that uploads a blob in blocks using the Azure Storage Rest API.

Answer 1

There is an Azure Storage Android library published here. A basic blob storage example is in the samples folder. The method you’d probably like to use is uploadFromFile in the blob class. This will, by default attempt to put the blob in a single put if the size is less than 64MB and otherwise send the blob in 4MB blocks. If you’d like to reduce the 64MB limit, you can set the singleBlobPutThresholdInBytes property on the BlobRequestOptions object of either the CloudBlobClient (which will affect all requests) or passed to the uploadFromFile method (to affect only that request). The storage library includes many convenient features such as automated retries and maximum execution timeout across the block put requests which are all configurable.

If you’d still like to use a more manual approach, the PutBlock and Put Block List API references are here and provide generic, cross-language documentation. These have nice wrappers in the CloudBlockBlob class of the Azure Storage Android library called uploadBlock and commitBlockList which may save you a lot of time in manual request construction and can provide some of the aforementioned conveniences.