Overload for put() OutputStream or allowing us to pass a Consumer<OutputStream>

[hakanai]

Many APIs don't give back an InputStream for streaming serialisation, but instead ask me to pass an OutputStream. For instance, [GSON.toJson](https://google-gson.googlecode.com/svn/trunk/gson/docs/javadocs/com/google/gson/Gson.html#toJson%28java.lang.Object, java.lang.Appendable%29) does this, GZIPOutputStream does as well, but all the custom filesystem APIs we use at work do the same thing, because it's more flexible.

So I would like an overload to put where I can either do this:

    getSardine().put(childUri.toString(), stream -> {
        // I write to stream
    });

or this:

    try (OutputStream stream = getSardine().put(childUri.toString())) {
        // I write to stream
    }

My workaround for the lack of it will be to create a Pipe and spin up an additional thread to do the copy, which is a little awkward.

[lookfirst]

Seems sane. Pull request?

[hakanai]

OK I hacked together the bits of it that I do know how to do, but there is a missing piece. The method taking an InputStream reuses org.apache.http.entity.InputStreamEntity.

Obviously I have to make an alternative version of this which accepts WriteLogic, which would be vaguely like this:

public class WriteLogicEntity extends AbstractHttpEntity
{
    private final WriteLogic writeLogic;

    public InputStreamEntity(WriteLogic writeLogic)
    {
        this(instream, null);
    }

    public InputStreamEntity(WriteLogic writeLogic, ContentType contentType)
    {
        this.writeLogic = writeLogic;
        if (contentType != null)
        {
            this.setContentType(contentType.toString());
        }
    }

    public boolean isRepeatable()
    {
        // because we don't really know
        return false;
    }

    public long getContentLength()
    {
        // because we don't really know
        return -1L;
    }

    public InputStream getContent() throws IOException
    {
        //TODO: What do we do here?
    }

    public void writeTo(OutputStream outstream) throws IOException
    {
        writeLogic.write(outstream);
    }

    public boolean isStreaming()
    {
        return true;
    }
}

It seems one way or another, an HttpEntity has to have a method returning InputStream. It isn't clear from their Javadoc what I'm supposed to do in this situation.

isStreaming() is also questionable. They give an incomplete list of examples:

• Streamed entities that read data directly from the socket should return true.
• Self-contained entities should return false.
• Wrapping entities should delegate this call to the wrapped entity.

Of which my implementation is none of the above.

I think I'm going to submit a ticket to them to improve the Javadoc and/or the interface...

[lookfirst]

👍

[hakanai]

Because I forgot to mention the issue in the commit, pull request #194 adds this.

[hakanai]

Perhaps of interest, I was eventually forced to stop doing it this way with Sardine, reason being that some implementations of the WriteLogic interface took a long time before they sent any data, but Sardine opens the connection immediately because it doesn't know either - end result is the server sometimes kicked you off if it thought your connection had stalled.

So now we write to a temp file and send it up using put(String,InputStream,Map). We can't use the method which takes File because (1) we use Path instead and (2) it doesn't have the Map overload which appears to be the only way to specify whether to overwrite or create a new file.