extensions/geode-modules/src/main/java/org/apache/geode/modules/session/catalina/JvmRouteBinderValve.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional information regarding
 * copyright ownership. The ASF licenses this file to You 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 org.apache.geode.modules.session.catalina;

import java.io.IOException;

import javax.servlet.ServletException;

import org.apache.catalina.Manager;
import org.apache.catalina.Session;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.valves.ValveBase;

public class JvmRouteBinderValve extends ValveBase {

  @Override
  public void invoke(Request request, Response response) throws IOException, ServletException {

    // Get the Manager
    Manager manager = request.getContext().getManager();

    // If it is an AbstractManager, handle possible failover
    if (manager instanceof DeltaSessionManager) {
      DeltaSessionManager absMgr = (DeltaSessionManager) manager;
      String localJvmRoute = absMgr.getJvmRoute();
      if (localJvmRoute != null) {
        handlePossibleFailover(request, absMgr, localJvmRoute);
      }
    }

    // Invoke the next Valve
    getNext().invoke(request, response);
  }

  private void handlePossibleFailover(Request request, DeltaSessionManager manager,
      String localJvmRoute) {
    String sessionId = request.getRequestedSessionId();
    if (sessionId != null) {
      // Get request JVM route
      String requestJvmRoute = null;
      int index = sessionId.indexOf(".");
      if (index > 0) {
        requestJvmRoute = sessionId.substring(index + 1);
      }

      // If the requested JVM route doesn't equal the session's JVM route, handle failover
      if (requestJvmRoute != null && !requestJvmRoute.equals(localJvmRoute)) {
        if (manager.getLogger().isDebugEnabled()) {
          String builder = this + ": Handling failover of session " + sessionId
              + " from " + requestJvmRoute + " to " + localJvmRoute;
          manager.getLogger().debug(builder);
        }
        // Get the original session
        Session session = null;
        try {
          session = manager.findSession(sessionId);
        } catch (IOException e) {
          String builder = this + ": Caught exception attempting to find session "
              + sessionId + " in " + manager;
          manager.getLogger().warn(builder, e);
        }

        if (session == null) {
          String builder = this + ": Did not find session " + sessionId
              + " to failover in " + manager;
          manager.getLogger().warn(builder);
        } else {
          // Change its session id. This removes the previous session and creates the new one.
          String baseSessionId = sessionId.substring(0, index);
          String newSessionId = baseSessionId + "." + localJvmRoute;
          session.setId(newSessionId);

          // Change the request's session id
          request.changeSessionId(newSessionId);
        }
      }
    }
  }
}