/**
* 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.
*/
package ch.ledcom.tomcat.valves;
import static java.lang.String.format;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.util.Enumeration;
import javax.annotation.Nullable;
import javax.servlet.ServletException;
import javax.servlet.http.HttpSession;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.valves.ValveBase;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import com.google.common.io.ByteStreams;
import com.google.common.io.Closer;
import com.google.common.io.CountingOutputStream;
/**
* Logs the size of the HTTP session.
*
* For this valve to work, a Java Agent must be registered to initialize the
* object-explorer introspection. See README.md for details.
*
* @author gehel
*/
public class SessionSizeValve extends ValveBase {
/** logger. */
private static Log log = LogFactory.getLog(SessionSizeValve.class);
/**
* Logs the size of the HTTP session.
*
* @param request
* the request being served
* @param response
* the response being generated
* @throws IOException
* @throws ServletException
*/
@Override
public final void invoke(final Request request, final Response response)
throws IOException, ServletException {
try {
getNext().invoke(request, response);
} finally {
try {
final long sessionSize = measureSerializedSessionSize(request
.getSession(false));
log.info(format("Session size = %d.", sessionSize));
} catch (final IOException ioe) {
log.warn("Problem measuring session size", ioe);
}
}
}
private long measureSerializedSessionSize(
@Nullable final HttpSession session) throws IOException {
if (session == null) {
return 0;
}
@SuppressWarnings("unchecked")
final Enumeration<String> attibuteNames = session.getAttributeNames();
long sessionSize = 0;
while (attibuteNames.hasMoreElements()) {
final String attributeName = attibuteNames.nextElement();
sessionSize += measureSerializedSize(session
.getAttribute(attributeName));
}
return sessionSize;
}
private long measureSerializedSize(final Object attribute)
throws IOException {
final Closer closer = Closer.create();
try {
final CountingOutputStream countingStream = closer
.register(new CountingOutputStream(ByteStreams
.nullOutputStream()));
final ObjectOutputStream out = closer
.register(new ObjectOutputStream(countingStream));
out.writeObject(attribute);
return countingStream.getCount();
} finally {
closer.close();
}
}
}