HttpUploadHandler.java

import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.jboss.netty.handler.codec.http.HttpChunk;
import org.jboss.netty.handler.codec.http.HttpRequest;
import org.jboss.netty.handler.codec.http.multipart.*;

/**
 * HttpUploadHandler provides an easy-to-use abstract handler for parsing multipart form data on the server.
 *
 * This code contains no license and is free for all to use. I would request that credit be given to me for any derived work though.
 *
 * @author Matt Hicks <matt@outr.com>
 */
public abstract class HttpUploadHandler extends SimpleChannelUpstreamHandler {
    private final DefaultHttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE);
    private HttpPostRequestDecoder decoder;

    @Override
    public void messageReceived(ChannelHandlerContext context, MessageEvent event) throws Exception {
        if (event.getMessage() instanceof HttpRequest) {
            HttpRequest request = (HttpRequest)event.getMessage();
            decoder = new HttpPostRequestDecoder(factory, request);
            if (!request.isChunked()) {
                uploadFinished(context);
            }
        } else if (event.getMessage() instanceof HttpChunk) {
            HttpChunk chunk = (HttpChunk)event.getMessage();
            decoder.offer(chunk);
            if (chunk.isLast()) {
                uploadFinished(context);
            }
        }
    }

    private void uploadFinished(ChannelHandlerContext context) throws HttpPostRequestDecoder.NotEnoughDataDecoderException {
        for (InterfaceHttpData data : decoder.getBodyHttpDatas()) {
            if (data instanceof Attribute) {
                receivedAttribute((Attribute)data);
            } else if (data instanceof FileUpload) {
                receivedFileUpload((FileUpload)data);
            }
        }
        sendResponse(context);
    }

    /**
     * Invoked when this upload handler receives a form attribute.
     */
    public abstract void receivedAttribute(Attribute attribute);

    /**
     * Invoked when this upload handler receives a file.
     */
    public abstract void receivedFileUpload(FileUpload upload);

    /**
     * Invoked after all upload data is received and a response should be sent back to the client.
     */
    public abstract void sendResponse(ChannelHandlerContext context);
}