/*
Copyright (c) 2012 LinkedIn Corp.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/* $Id$ */
package com.linkedin.r2.transport.http.server;
import java.net.URISyntaxException;
import javax.mail.MessagingException;
import javax.servlet.AsyncContext;
import javax.servlet.AsyncEvent;
import javax.servlet.AsyncListener;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.linkedin.r2.message.RequestContext;
import com.linkedin.r2.message.rest.RestRequest;
import com.linkedin.r2.message.rest.RestResponse;
import com.linkedin.r2.message.rest.RestStatus;
import com.linkedin.r2.transport.common.bridge.common.TransportCallback;
import com.linkedin.r2.transport.common.bridge.common.TransportResponse;
import java.io.IOException;
/**
* Abstract Async R2 Servlet. Any servlet deriving from this class can only be used with
* containers supporting Servlet API 3.0 or greater.
* @author Goksel Genc
* @version $Revision$
*/
public abstract class AbstractAsyncR2Servlet extends AbstractR2Servlet
{
private static final String TRANSPORT_CALLBACK_IOEXCEPTION = "TransportCallbackIOException";
// servlet async context timeout in ms.
private final long _timeout;
/**
* Initialize the servlet, optionally using servlet-api-3.0 async API, if supported
* by the container. The latter is checked later in init()
*/
public AbstractAsyncR2Servlet(long timeout)
{
_timeout = timeout;
}
@Override
public void service(final HttpServletRequest req, final HttpServletResponse resp) throws ServletException,
IOException
{
RestRequest restRequest;
try
{
restRequest = readFromServletRequest(req);
}
catch (URISyntaxException e)
{
writeToServletError(resp, RestStatus.BAD_REQUEST, e.toString());
return;
}
catch (MessagingException e)
{
writeToServletError(resp, RestStatus.BAD_REQUEST, e.toString());
return;
}
RequestContext requestContext = readRequestContext(req);
final AsyncContext ctx = req.startAsync(req, resp);
ctx.setTimeout(_timeout);
ctx.addListener(new AsyncListener()
{
@Override
public void onTimeout(AsyncEvent event) throws IOException
{
AsyncContext ctx = event.getAsyncContext();
writeToServletError((HttpServletResponse) ctx.getResponse(),
RestStatus.INTERNAL_SERVER_ERROR,
"Server Timeout");
ctx.complete();
}
@Override
public void onStartAsync(AsyncEvent event) throws IOException
{
// Nothing to do here
}
@Override
public void onError(AsyncEvent event) throws IOException
{
writeToServletError((HttpServletResponse) event.getSuppliedResponse(),
RestStatus.INTERNAL_SERVER_ERROR,
"Server Error");
ctx.complete();
}
@Override
public void onComplete(AsyncEvent event) throws IOException
{
Object exception = req.getAttribute(TRANSPORT_CALLBACK_IOEXCEPTION);
if (exception != null)
throw new IOException((IOException) exception);
}
});
TransportCallback<RestResponse> callback = new TransportCallback<RestResponse>()
{
@Override
public void onResponse(TransportResponse<RestResponse> response)
{
try
{
writeToServletResponse(response, (HttpServletResponse) ctx.getResponse());
}
catch (IOException e)
{
req.setAttribute(TRANSPORT_CALLBACK_IOEXCEPTION, e);
}
finally
{
ctx.complete();
}
}
};
getDispatcher().handleRequest(restRequest, requestContext, callback);
}
public long getTimeout()
{
return _timeout;
}
}