HttpDispatcher.java example

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swellrt-master
package org.swellrt.server.box.events.http;


import java.io.IOException;
import java.nio.charset.Charset;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.methods.ByteArrayRequestEntity;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.RequestEntity;
import org.json.JSONException;
import org.json.JSONObject;
import org.swellrt.server.box.events.Event;
import org.swellrt.server.box.events.EventDispatcherTarget;
import org.swellrt.server.box.events.EventRule;
import org.waveprotocol.box.server.executor.ExecutorAnnotations.DispatcherExecutor;
import org.waveprotocol.wave.util.logging.Log;

import com.google.common.util.concurrent.ListenableFutureTask;
import com.google.inject.Inject;
import com.typesafe.config.Config;
import com.typesafe.config.ConfigException;

/**
 * Dispatch events to HTTP endpoints depending of events
 * 
 * @author pablojan@gmail.com (Pablo Ojanguren)
 *
 */
public class HttpDispatcher implements EventDispatcherTarget {
	
	private static final Log LOG = Log.get(HttpDispatcher.class);
	
	public static final String NAME = "http";
	private static final String CONFIG_PREFIX = "dispatch."+NAME;
	
	private final Config config;
	private final Executor executor;
	
	@Inject
	public HttpDispatcher(Config config, @DispatcherExecutor Executor dispatcherExecutor) {
		this.config = config;
		this.executor = dispatcherExecutor;
	}
	
	@Override
	public String getName() {
		return NAME;
	}

	@Override
	public void dispatch(final EventRule rule, final Event event, final String payload) {
				
		ListenableFutureTask<Void> task = ListenableFutureTask.create(new Callable<Void>() {

			@Override
			public Void call() throws Exception {

				HttpClient httpClient = new HttpClient();
				String configBasePath = CONFIG_PREFIX + "." + rule.getId() + ".";
				PostMethod request = null;

				try {

					String host = config.getString(configBasePath + "host");
					String contentType = config.getString(configBasePath + "contentType");
					List<String> headers = config.getStringList(configBasePath + "headers");

					request = new PostMethod(host);

					request.setRequestHeader("Content-Type", contentType);
					for (String h : headers) {
						String[] headerParts = h.split(":");
						if (headerParts != null && headerParts.length == 2)
							request.setRequestHeader(headerParts[0], headerParts[1]);
					}

					JSONObject jsonData = new JSONObject();

					jsonData.put("waveid", event.getWaveId().serialise());
					// jsonData.put("waveletid", event.getWaveletId().getId());
					// jsonData.put("blipid", event.getBlipId());
					jsonData.put("path", event.getPath());
					jsonData.put("data", new JSONObject(payload));

					LOG.info("HTTP dispatcher. Message to send: " + jsonData.toString());

					RequestEntity requestData = new ByteArrayRequestEntity(
							jsonData.toString().getBytes(Charset.forName("UTF-8")));
					request.setRequestEntity(requestData);

					int resultCode = httpClient.executeMethod(request);

					if (resultCode != HttpStatus.SC_OK) {
						LOG.severe("HTTP dispatcher error, response status " + resultCode);
					}

				} catch (JSONException e) {
					LOG.severe("HTTP dispatcher error", e);

				} catch (HttpException e) {
					LOG.severe("HTTP dispatcher error", e);

				} catch (IOException e) {
					LOG.severe("HTTP dispatcher error", e);

				} catch (ConfigException e) {
					LOG.severe("HTTP dispatcher, configuration error", e);
				} finally {
					if (request != null)
						request.releaseConnection();
				}
				
				return null;
			}

		});
		
		executor.execute(task);
	}

}