Question

I’m pretty new to coding with streams but now I have to do it for more efficient Http coding.

Here is code that I wrote(not working) to get ContentProducer for HttpClient:

public static ContentProducer getContentProducer(final Context context, final UUID gId)
    {
        return new ContentProducer()
        {
            public void writeTo(OutputStream outputStream) throws IOException
            {
                outputStream = new Base64.OutputStream(new FileOutputStream(StorageManager.getFileFromName(context, gId.toString())));

                outputStream.flush();
            }
        };
    }

I’m using Base64 streaming encoder from here: http://iharder.sourceforge.net/current/java/base64/
My goal is to use this function to provide data that I read from binary file to HttpClient as base64 encoded stream.

This is how I consume content producers:

private MyHttpResponse processPOST(String url, ContentProducer requestData)
    {
        MyHttpResponse response = new MyHttpResponse();

        try
        {
            HttpPost request = new HttpPost(serviceURL + url);
            HttpEntity entity = new EntityTemplate(requestData);
            request.setEntity(entity);

            ResponseHandler<String> handler = new BasicResponseHandler();
            response.Body = mHttpClient.execute(request, handler);
        }
        catch (HttpResponseException e)
        {

        }
        catch (Throwable e)
        {

        }

        return response;
    }

I have another ContentProducer which works with GSON streamer(and it’s working):

public ContentProducer getContentProducer(final Context context)
    {
        return new ContentProducer()
        {
            public void writeTo(OutputStream outputStream) throws IOException
            {
                Gson myGson = MyGsonWrapper.getMyGson();
                JsonWriter writer = new JsonWriter(new OutputStreamWriter(outputStream, "UTF-8"));

                writer.beginObject();

                // stuff

                writer.endObject();

                writer.flush();
            }
        };
    }

My question is: How to make my first example work. Am I doing it correctly? Right now I get empty post on server side, so it seems like no data coming through.

Answer 1

EDIT:

I believe that the issue is that you are being passed an OutputStream in your ContentProviders writeTo() method, and you are overwriting it with your own OutputStream. The contract of that class/method probably requires you to write your data to the OutputStream passed to you.

Based on looking at the Android Documentation, I do not see a way for you to specify the OutputStream to use, so you will probably need to just write out the data of the file to the OutputStream that is passed in.

Instead, you should do something like this:

public void writeTo(OutputStream outputStream) throws IOException
{
    byte[] buf = createByteBufferFromFile(StorageManager.getFileFromName(context, gId.toString()));
    outputStream.write(buf);
    outputStream.flush();
}

Of course you will need to provide an implementation to the createByteBufferFromFile(…) method that I mention. Again, you should note that it is not likely that you will be using the Base64 OutputStream, so if that is a necessity, then you may have to find a different approach.