ResponseHandlerFilter.java

/**
 * Copyright 2016 Yahoo Inc.
 *
 * 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 com.yahoo.pulsar.broker.web;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.ws.rs.core.Response.Status;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.yahoo.pulsar.broker.PulsarService;

/**
 * Servlet filter that hooks up to handle outgoing response
 */
public class ResponseHandlerFilter implements Filter {
    private static final Logger LOG = LoggerFactory.getLogger(ResponseHandlerFilter.class);

    private final String brokerAddress;

    public ResponseHandlerFilter(PulsarService pulsar) {
        this.brokerAddress = pulsar.getAdvertisedAddress();
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {

        chain.doFilter(request, response);
        ((HttpServletResponse) response).addHeader("broker-address", brokerAddress);
        if (((HttpServletResponse) response).getStatus() == Status.INTERNAL_SERVER_ERROR.getStatusCode()) {
            // invalidate current session from servlet-container if it received internal-server-error 
            try {
                ((HttpServletRequest) request).getSession(false).invalidate();
            } catch (Exception ignoreException) {
                /* connection is already invalidated */
            }
        }

    }

    @Override
    public void init(FilterConfig arg) throws ServletException {
        // No init necessary.
    }

    @Override
    public void destroy() {
        // No state to clean up.
    }
}