//
//  ========================================================================
//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.server.handler;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Server;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/* ------------------------------------------------------------ */
/**
 * A handler that shuts the server down on a valid request. Used to do "soft" restarts from Java. If _exitJvm ist set to true a hard System.exit() call is being
 * made.
 *
 * This handler is a contribution from Johannes Brodwall: https://bugs.eclipse.org/bugs/show_bug.cgi?id=357687
 *
 * Usage:
 *
 * <pre>
	Server server = new Server(8080);
	HandlerList handlers = new HandlerList();
	handlers.setHandlers(new Handler[]
	{ someOtherHandler, new ShutdownHandler(server,&quot;secret password&quot;) });
	server.setHandler(handlers);
	server.start();
   </pre>
 * 
   <pre>
   public static void attemptShutdown(int port, String shutdownCookie) {
		try {
			URL url = new URL("http://localhost:" + port + "/shutdown?token=" + shutdownCookie);
			HttpURLConnection connection = (HttpURLConnection)url.openConnection();
			connection.setRequestMethod("POST");
			connection.getResponseCode();
			logger.info("Shutting down " + url + ": " + connection.getResponseMessage());
		} catch (SocketException e) {
			logger.debug("Not running");
			// Okay - the server is not running
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}
  </pre>
 */
public class ShutdownHandler extends AbstractHandler
{
	private static final Logger LOG = LoggerFactory.getLogger(ShutdownHandler.class);

	private final String _shutdownToken;

	private final Server _server;

	private boolean _exitJvm = false;
  
	

	/**
	 * Creates a listener that lets the server be shut down remotely (but only from localhost).
	 *
	 * @param server
	 *            the Jetty instance that should be shut down
	 * @param shutdownToken
	 *            a secret password to avoid unauthorized shutdown attempts
	 */
	public ShutdownHandler(Server server, String shutdownToken)
	{
		this._server = server;
		this._shutdownToken = shutdownToken;
	}

	@Override
	public void handle(String target, Request request, HttpServletResponse response) throws IOException, ServletException
	{
		if (!target.equals("/shutdown"))
		{
			return;
		}

		if (!request.getMethod().equals("POST"))
		{
			response.sendError(HttpServletResponse.SC_BAD_REQUEST);
			return;
		}
		if (!hasCorrectSecurityToken(request))
		{
			LOG.warn("Unauthorized shutdown attempt from " + getRemoteAddr(request));
			response.sendError(HttpServletResponse.SC_UNAUTHORIZED);
			return;
		}
		if (!requestFromLocalhost(request))
		{
			LOG.warn("Unauthorized shutdown attempt from " + getRemoteAddr(request));
			response.sendError(HttpServletResponse.SC_UNAUTHORIZED);
			return;
		}

		LOG.info("Shutting down by request from " + getRemoteAddr(request));
		
		new Thread()
		{
			public void run ()
			{
				try
				{
					shutdownServer();
				}
				catch (InterruptedException e)
				{
					LOG.trace("",e);
				}
				catch (Exception e)
				{
					throw new RuntimeException("Shutting down server",e);
				}
			}
		}.start();
	}

	private boolean requestFromLocalhost(Request request)
	{
		return "127.0.0.1".equals(getRemoteAddr(request));
	}

	protected String getRemoteAddr(Request request)
	{
		return request.getRemoteAddr();
	}

	private boolean hasCorrectSecurityToken(Request request)
	{
		return _shutdownToken.equals(request.getParameter("token"));
	}

	private void shutdownServer() throws Exception
	{
		_server.stop();
		
		if (_exitJvm)
		{
			System.exit(0);
		}
	}

	public void setExitJvm(boolean exitJvm)
	{
		this._exitJvm = exitJvm;
	}

}