BackendGossipHandler.java

import java.io.IOException;
import java.net.URLDecoder;
import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.MethodNotSupportedException;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpRequestHandler;
import org.apache.http.util.EntityUtils;
import org.apache.log4j.Logger;

public class BackendGossipHandler implements HttpRequestHandler {

	private static Logger log = Logger.getLogger(BackendGossipHandler.class);
	
	public void handle(final HttpRequest request, final HttpResponse response,
			final HttpContext context) throws HttpException, IOException {

		log.info("Backend: Handling StatusUpdate; Line = "
				+ request.getRequestLine());
		String method = request.getRequestLine().getMethod()
				.toUpperCase(Locale.ENGLISH);

		if (method.equals("POST")) {
			final String target = request.getRequestLine().getUri();
			Pattern p_uri = Pattern.compile("/data/gossip\\?s=(.*)$");
			Pattern p_body = Pattern.compile("/data/gossip");
			Matcher m_uri = p_uri.matcher(target);
			Matcher m_body = p_body.matcher(target);
			String message = null;
			if (m_uri.find()) {
				message = m_uri.group(1);
			} else if (m_body.find()) {
				HttpEntity entity = ((HttpEntityEnclosingRequest) request)
						.getEntity();
				String entityContent = EntityUtils.toString(entity);
				
				Pattern p = Pattern.compile("s=(.*)$");
				Matcher m = p.matcher(entityContent);
				if (m.find()) {
					message = m.group(1);
				}
			} else {
				response.setStatusCode(HttpStatus.SC_BAD_REQUEST);
				return;
			}
			
			if (message != null) {
				JSONgossipMessage j = WebServer.g.fromJson(URLDecoder.decode(message, "UTF-8"), JSONgossipMessage.class);
				ServerStateManager.mergeInfo(j.snapshot);
				ServerStateManager.getSnapshot().get(j.myState.getID()).updateLastSeen();
				if (j.tweets != null && j.tweets.size() > 0) {
					BackendDataStorage bds = BackendDataStorage.getInstance();
					bds.mergeTweets(j.tweets, j.myState.getClockVal());
				}
			} else {
				response.setStatusCode(HttpStatus.SC_BAD_REQUEST);
			}
		} else {
			throw new MethodNotSupportedException(method
					+ " method not supported\n");
		}

	}

}